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<p>w</p><p>1</p><p>OrcaFlex Manual</p><p>Version 9.6a</p><p>Orcina Ltd.</p><p>Daltongate</p><p>Ulverston</p><p>Cumbria</p><p>LA12 7AJ</p><p>UK</p><p>Telephone: +44 (0) 1229 584742</p><p>Fax: +44 (0) 1229 587191</p><p>E-mail: orcina@orcina.com</p><p>Web Site: www.orcina.com</p><p>mailto:orcina@orcina.com</p><p>http://www.orcina.com/</p><p>w Contents</p><p>3</p><p>CONTENTS</p><p>1 INTRODUCTION 11</p><p>1.1 Installing OrcaFlex 11</p><p>1.2 Running OrcaFlex 13</p><p>1.3 Parallel Processing 14</p><p>1.4 Distributed OrcaFlex 15</p><p>1.5 Orcina Licence Monitor 15</p><p>1.6 Demonstration Version 15</p><p>1.7 OrcaFlex Examples 15</p><p>1.8 Validation and QA 15</p><p>1.9 Orcina 15</p><p>1.10 References and Links 16</p><p>2 TUTORIAL 21</p><p>2.1 Getting Started 21</p><p>2.2 Building a Simple System 21</p><p>2.3 Adding a Line 21</p><p>2.4 Adjusting the View 22</p><p>2.5 Static Analysis 22</p><p>2.6 Dynamic Analysis 23</p><p>2.7 Multiple Views 23</p><p>2.8 Looking at Results 24</p><p>2.9 Getting Output 24</p><p>2.10 Input Data 24</p><p>3 USER INTERFACE 25</p><p>3.1 Introduction 25</p><p>3.1.1 Program Windows 25</p><p>3.1.2 The Model 25</p><p>3.1.3 Model States 26</p><p>3.1.4 Toolbar 27</p><p>3.1.5 Status Bar 28</p><p>3.1.6 Mouse and Keyboard Actions 28</p><p>3.2 OrcaFlex Model Files 31</p><p>3.2.1 Data Files 31</p><p>3.2.2 Text Data Files 32</p><p>3.2.3 Simulation Files 36</p><p>3.3 Model Browser 37</p><p>3.3.1 Model Browser Views 39</p><p>3.3.2 Move Selected Objects Wizard 39</p><p>Contents w</p><p>4</p><p>3.4 Libraries 40</p><p>3.4.1 Using Libraries 41</p><p>3.4.2 Building a Library 44</p><p>3.5 Menus 44</p><p>3.5.1 File Menu 45</p><p>3.5.2 Edit Menu 46</p><p>3.5.3 Model Menu 46</p><p>3.5.4 Calculation Menu 48</p><p>3.5.5 View Menu 49</p><p>3.5.6 Replay Menu 49</p><p>3.5.7 Graph Menu 50</p><p>3.5.8 Results Menu 50</p><p>3.5.9 Tools Menu 50</p><p>3.5.10 Workspace Menu 51</p><p>3.5.11 Window Menu 51</p><p>3.5.12 Help Menu 52</p><p>3.6 3D Views 52</p><p>3.6.1 View Parameters 53</p><p>3.6.2 View Control 54</p><p>3.6.3 Navigating in 3D Views 54</p><p>3.6.4 Shaded Graphics 55</p><p>3.6.5 How Objects are Drawn 57</p><p>3.6.6 Selecting Objects 59</p><p>3.6.7 Creating and Destroying Objects 59</p><p>3.6.8 Dragging Objects 59</p><p>3.6.9 Connecting Objects 59</p><p>3.6.10 Printing, Copying and Exporting Views 60</p><p>3.7 Replays 60</p><p>3.7.1 Replay Parameters 60</p><p>3.7.2 Replay Control 61</p><p>3.7.3 Custom Replays 62</p><p>3.7.4 Custom Replay Wizard 62</p><p>3.8 Data Forms 63</p><p>3.8.1 Data Fields 64</p><p>3.8.2 Data Form Editing 65</p><p>3.9 Results 66</p><p>3.9.1 Producing Results 66</p><p>3.9.2 Selecting Variables 68</p><p>3.9.3 Summary and Full Results 68</p><p>3.9.4 Statistics 69</p><p>3.9.5 Linked Statistics 69</p><p>3.9.6 Offset Tables 69</p><p>3.9.7 Line Clashing Report 70</p><p>3.9.8 Time History and XY Graphs 71</p><p>3.9.9 Range Graphs 72</p><p>3.9.10 Offset Graphs 73</p><p>3.9.11 Spectral Response Graphs 73</p><p>3.9.12 Extreme Value Statistics Results 73</p><p>w Contents</p><p>5</p><p>3.9.13 Presenting OrcaFlex Results 76</p><p>3.10 Graphs 77</p><p>3.10.1 Modifying Graphs 78</p><p>3.11 Spreadsheets 79</p><p>3.12 Text Windows 79</p><p>3.13 Workspaces 79</p><p>3.14 Comparing Data 80</p><p>3.15 Preferences 81</p><p>3.16 Printing and Exporting 83</p><p>4 AUTOMATION 85</p><p>4.1 Introduction 85</p><p>4.2 Batch Processing 85</p><p>4.2.1 Introduction 85</p><p>4.2.2 Script Files 87</p><p>4.2.3 Script Syntax 87</p><p>4.2.4 Script Commands 87</p><p>4.2.5 Examples of setting data 91</p><p>4.2.6 Handling Script Errors 96</p><p>4.2.7 Obtaining Variable Names 97</p><p>4.2.8 Automating Script Generation 97</p><p>4.3 Text Data Files 99</p><p>4.3.1 Examples of setting data 99</p><p>4.3.2 Automating Generation 106</p><p>4.4 Post-processing 107</p><p>4.4.1 Introduction 107</p><p>4.4.2 OrcaFlex Spreadsheet 107</p><p>4.4.3 Instruction Format 111</p><p>4.4.4 Pre-defined commands 112</p><p>4.4.5 Basic commands 113</p><p>4.4.6 Time History and related commands 114</p><p>4.4.7 Range Graph commands 115</p><p>4.4.8 Data commands 115</p><p>4.4.9 Instructions Wizard 116</p><p>4.4.10 Duplicate Instructions 119</p><p>5 THEORY 123</p><p>5.1 Coordinate Systems 123</p><p>5.2 Direction Conventions 124</p><p>5.3 Object Connections 125</p><p>5.4 Interpolation Methods 125</p><p>5.5 Static Analysis 127</p><p>5.5.1 Line Statics 127</p><p>5.5.2 Buoy and Vessel Statics 131</p><p>5.5.3 Vessel Multiple Statics 131</p><p>Contents w</p><p>6</p><p>5.6 Dynamic Analysis 132</p><p>5.6.1 Calculation Method 133</p><p>5.6.2 Ramping 135</p><p>5.7 Friction Theory 135</p><p>5.8 Spectral Response Analysis 138</p><p>5.9 Extreme Value Statistics Theory 139</p><p>5.10 Environment Theory 141</p><p>5.10.1 Buoyancy Variation with Depth 141</p><p>5.10.2 Current Theory 141</p><p>5.10.3 Seabed Theory 142</p><p>5.10.4 Seabed Non-Linear Soil Model Theory 143</p><p>5.10.5 Morison's Equation 149</p><p>5.10.6 Waves 150</p><p>5.11 Vessel Theory 157</p><p>5.11.1 Vessel Rotations 157</p><p>5.11.2 RAOs and Phases 158</p><p>5.11.3 RAO Quality Checks 160</p><p>5.11.4 Current and Wind Loads 161</p><p>5.11.5 Stiffness, Added Mass and Damping 164</p><p>5.11.6 Impulse Response and Convolution 165</p><p>5.11.7 Wave Drift and Sum Frequency Loads 166</p><p>5.11.8 Manoeuvring Load 171</p><p>5.11.9 Other Damping 171</p><p>5.12 Line Theory 172</p><p>5.12.1 Overview 172</p><p>5.12.2 Structural Model Details 174</p><p>5.12.3 Calculation Stages 175</p><p>5.12.4 Calculation Stage 1 Tension Forces 175</p><p>5.12.5 Calculation Stage 2 Bend Moments 176</p><p>5.12.6 Calculation Stage 3 Shear Forces 179</p><p>5.12.7 Calculation Stage 4 Torsion Moments 179</p><p>5.12.8 Calculation Stage 5 Total Load 180</p><p>5.12.9 Line End Orientation 180</p><p>5.12.10 Line Local Orientation 181</p><p>5.12.11 Treatment of Compression 181</p><p>5.12.12 Contents Flow Effects 182</p><p>5.12.13 Line Pressure Effects 183</p><p>5.12.14 Pipe Stress Calculation 184</p><p>5.12.15 Pipe Stress Matrix 185</p><p>5.12.16 Hydrodynamic and Aerodynamic Loads 187</p><p>5.12.17 Drag Chains 189</p><p>5.12.18 Line End Conditions 191</p><p>5.12.19 Interaction with the Sea Surface 191</p><p>5.12.20 Interaction with Seabed and Shapes 192</p><p>5.12.21 Clashing 192</p><p>5.13 6D Buoy Theory 195</p><p>5.13.1 Overview 195</p><p>5.13.2 Lumped Buoy Added Mass, Damping and Drag 197</p><p>w Contents</p><p>7</p><p>5.13.3 Spar Buoy and Towed Fish Added Mass and Damping 198</p><p>5.13.4 Spar Buoy and Towed Fish Drag 201</p><p>5.13.5 Slam Force 203</p><p>5.13.6 Contact Forces 205</p><p>5.14 3D Buoy Theory 205</p><p>5.15 Winch Theory 206</p><p>5.16 Shape Theory 208</p><p>6 SYSTEM MODELLING: DATA AND RESULTS 211</p><p>6.1 Modelling Introduction 211</p><p>6.2 Data in Time History Files 212</p><p>6.3 Variable Data 214</p><p>6.3.1 External Functions 215</p><p>6.4 General Data 217</p><p>6.4.1 Statics 217</p><p>6.4.2 Dynamics 219</p><p>6.4.3 Integration & Time Steps 220</p><p>6.4.4 Explicit Integration 220</p><p>6.4.5 Implicit Integration 222</p><p>6.4.6 Numerical Damping 223</p><p>6.4.7 Response Calculation 223</p><p>6.4.8 Results 223</p><p>6.4.9 Drawing 224</p><p>6.4.10 Properties Report 224</p><p>6.5 Environment 225</p><p>6.5.1 Sea Data 225</p><p>6.5.2 Sea Density Data 226</p><p>6.5.3 Seabed Data 227</p><p>6.5.4 Wave Data 230</p><p>6.5.5 Data for Regular Waves 232</p><p>6.5.6 Data for Random Waves 232</p><p>6.5.7 Data for JONSWAP and ISSC Spectra 233</p><p>6.5.8 Data for Ochi-Hubble Spectrum 234</p><p>6.5.9 Data for Torsethaugen Spectrum 235</p><p>6.5.10 Data for Gaussian Swell Spectrum 235</p><p>6.5.11 Data for User Defined Spectrum 235</p><p>6.5.12 Data for Time History Waves 236</p><p>6.5.13 Data for User Specified Components 237</p><p>6.5.14 Data for Response Calculation 237</p><p>6.5.15 Waves Preview 237</p><p>6.5.16 Modelling Design Waves 238</p><p>6.5.17 Setting up a Random Sea 240</p><p>6.5.18 Current Data 242</p><p>6.5.19 Wind Data 244</p><p>6.5.20 Drawing Data 245</p><p>6.5.21 External Functions 246</p><p>6.5.22 Results 246</p><p>Contents w</p><p>8</p><p>6.5.23 Wave Scatter Conversion 247</p><p>6.6 Solid Friction Coefficients Data 251</p><p>6.7 Vessels 252</p><p>6.7.1 Vessel Modelling Overview 254</p><p>6.7.2 Vessel Data 255</p><p>6.7.3 Vessel Types 264</p><p>6.7.4 Modelling Vessel Slow Drift 292</p><p>6.7.5 Vessel Response Reports 294</p><p>6.7.6 Vessel Results 296</p><p>6.8 Lines 300</p><p>6.8.1 Line Data 302</p><p>6.8.2 Line Types 318</p><p>6.8.3 Attachments 330</p><p>6.8.4 Line Contact 334</p><p>6.8.5 Rayleigh Damping 342</p><p>6.8.6 P-y Models 345</p><p>6.8.7 Line Results 348</p><p>6.8.8 Drag Chain Results 360</p><p>6.8.9 Flex Joint Results 361</p><p>6.8.10 Line Setup Wizard 361</p><p>6.8.11 Line Type Wizard 362</p><p>6.8.12 Chain 363</p><p>6.8.13 Rope/Wire 368</p><p>6.8.14 Line with Floats 371</p><p>6.8.15 Homogeneous Pipe 375</p><p>6.8.16 Hoses and Umbilicals 377</p><p>6.8.17 Modelling Stress Joints 379</p><p>6.8.18 Modelling Bend Restrictors 381</p><p>6.8.19 Modelling non-linear homogeneous pipes 383</p><p>6.8.20 Line Ends 385</p><p>6.8.21 Modelling Compression in Flexibles 388</p><p>6.9 6D</p><p>much easier to build and inspect using the full capabilities and visualisation</p><p>strengths of OrcaFlex. On the other hand, text data files can be very effective when making minor changes to existing</p><p>models. Using text data files for such minor variations of existing models makes it much easier to monitor just what</p><p>has been changed, for example by using standard text differencing programs.</p><p>Text data files are highly readable and self-documenting which makes them ideal for QA and archival purposes.</p><p>Another application well suited to the use of text data files is automation.</p><p>3.2.2 Text Data Files</p><p>Text data files are used to define and represent OrcaFlex models in a human readable and easily editable format.</p><p>Text data files can be opened and saved by OrcaFlex. A very simple example is shown below:</p><p>General:</p><p>StageDuration:</p><p>- 10.0</p><p>- 50.0</p><p>Lines:</p><p>- Name: Line1</p><p>Length, TargetSegmentLength:</p><p>- [60.0, 5.0]</p><p>- [40.0, 2.0]</p><p>- [120.0, 10.0]</p><p>This example first defines a 10s build-up stage followed by stage 1 with 50s duration. Then a Line is created and</p><p>named "Line1". Finally the section data is specified: three sections are created with varying section lengths and</p><p>segment lengths. Default values are used for all data which are not specified.</p><p>Note: The formatting (colour, bold, italic etc.) in the examples here has been added to aid readability,</p><p>and is not a feature or requirement of text data files themselves.</p><p>YAML file format</p><p>Text data files use a standard file format called YAML and should be saved with the .yml file extension. The YAML file</p><p>format was chosen because it is extremely easy to read and write.</p><p>YAML files are plain text files and so can be edited in any text editor. We have found Notepad++ to be a very effective</p><p>editor for YAML files. Notepad++ has a tabbed interface for easy editing of multiple files and has code folding and</p><p>syntax highlighting facilities that work well with YAML files.</p><p>Note: YAML files must be saved with the UTF-8 character encoding.</p><p>More details on the YAML format and Notepad++ can be obtained from the following web sites:</p><p> http://en.wikipedia.org/wiki/YAML – YAML page on Wikipedia.</p><p> http://www.yaml.org/ – Official YAML homepage.</p><p> http://www.yaml.org/spec/ – Complete technical specification of YAML.</p><p> http://notepad-plus.sourceforge.net/ – Notepad++.</p><p>Elements of a text data file</p><p>The most basic element of a text data file is the name/value pair:</p><p>UnitsSystem: SI</p><p>The name (UnitsSystem) is written first, followed by a colon (:), then a SPACE, and then the value (SI). The names</p><p>used in text data files are the same as used to identify data items in batch script files.</p><p>Names and values in YAML files can contain spaces and other punctuation:</p><p>http://en.wikipedia.org/wiki/YAML</p><p>http://www.yaml.org/</p><p>http://www.yaml.org/spec/</p><p>http://notepad-plus.sourceforge.net/</p><p>w User Interface, OrcaFlex Model Files</p><p>33</p><p>General:</p><p>StaticsMethod: Whole System statics</p><p>Lines:</p><p>- Name: 12" Riser</p><p>- Name: Umbilical, upper</p><p>- Name: £"!$%^&*(){}[]=+-_#~'@:;/?.>,<\|</p><p>This example also contains a list. New items in a list are introduced by a dash (-) followed by a SPACE. Items in a list</p><p>can span more than a single line:</p><p>Lines:</p><p>- Name: Riser</p><p>TopEnd: End B</p><p>ContentsDensity: 0.8</p><p>- Name: Umbilical</p><p>TopEnd: End A</p><p>ContentsDensity: 0.0</p><p>Outline indentation is used to delimit blocks in a YAML file. This concept, known as significant indentation, is</p><p>perhaps a little unusual as most data formats and programming languages use symbols to indicate the beginnings</p><p>and ends of blocks. To understand this better consider the following example:</p><p>General:</p><p>UnitsSystem: SI</p><p>StaticsMethod: Whole System statics</p><p>Environment:</p><p>WaterDepth: 80</p><p>The two lines immediately following General: which are indented by two spaces, form a single block. This block is</p><p>ended by Environment: because it is not indented. A second block follows Environment: containing a single</p><p>name/value pair which defines the water depth.</p><p>Indentation must be made with SPACE characters rather than TAB characters. It does not matter how many spaces</p><p>are used so long as the indentation is consistent within each block. However, it is good practice to use the same</p><p>indentation throughout a file. OrcaFlex itself uses indentation of two spaces when it writes YAML files.</p><p>Lists are commonly used to represent tables of data:</p><p>Lines:</p><p>- Name: Line1</p><p>LineType, Length, TargetSegmentLength:</p><p>- [Line Type1, 60, 5]</p><p>- [Line Type1, 40, 2]</p><p>- [Line Type2, 120, 10]</p><p>The name LineType, Length, TargetSegmentLength indicates three columns of data, LineType, Length</p><p>and TargetSegmentLength which are interpreted in that order. The comma (,) character is used as a separator.</p><p>Note that you do not have to present the data in the same order as it appears in OrcaFlex. The following example is</p><p>equivalent to the previous example:</p><p>Lines:</p><p>- Name: Line1</p><p>Length, TargetSegmentLength, LineType:</p><p>- [60, 5, Line Type1]</p><p>- [40, 2, Line Type1]</p><p>- [120, 10, Line Type2]</p><p>You can, if you wish, omit columns, in which case default values will be used:</p><p>Lines:</p><p>- Name: Line1</p><p>LineType, Length:</p><p>- [Line Type1, 60]</p><p>- [Line Type1, 40]</p><p>- [Line Type2, 120]</p><p>Some data are closely related to each other and can naturally be grouped in a text data file:</p><p>User Interface, OrcaFlex Model Files w</p><p>34</p><p>3DBuoys:</p><p>- Name: 3D Buoy1</p><p>InitialPosition: [0, 0, 10]</p><p>DragArea: [100, 100, 30]</p><p>Pen: [4, Solid, Yellow]</p><p>Without grouping the file would be significantly longer:</p><p>3DBuoys:</p><p>- Name: 3D Buoy1</p><p>InitialX: 0</p><p>InitialY: 0</p><p>InitialZ: 10</p><p>DragAreaX: 100</p><p>DragAreaY: 100</p><p>DragAreaZ: 30</p><p>PenWidth: 4</p><p>PenStyle: Solid</p><p>PenColour: Yellow</p><p>The majority of grouped data are X,Y,Z components and we adopt the convention that these components appear in</p><p>that order when grouped.</p><p>YAML files may contain comments which are introduced by a hash (#) character followed by a SPACE. All</p><p>subsequent text on the same line is comment and is ignored when OrcaFlex reads a text data file. Comments are not</p><p>preserved by OrcaFlex and any user comments in a manually edited YAML file opened with OrcaFlex will be lost if</p><p>the file is saved. Comments are formatted in green in the following example:</p><p>General:</p><p># Statics</p><p>StaticsMethod: Whole System statics</p><p>BuoysIncludedInStatics: Individually Specified</p><p># Dynamics</p><p>StageDuration:</p><p>- 8</p><p>- 16</p><p>TargetLogSampleInterval: 0.1</p><p># Integration</p><p>SimulationIntegrationMethod: Implicit</p><p>ImplicitConstantTimeStep: 0.1</p><p>A text data file can be rather large, particularly if it contains vessel hydrodynamic data. Code folding editors can help</p><p>somewhat, but even so such files can be awkward to work with. The IncludeFile identifier allows you to move</p><p>data into a separate file which is then included in the main file:</p><p># File: C:\Desktop\main.yml</p><p>VesselTypes:</p><p>- Name: FPSO</p><p>IncludeFile: FPSO.yml</p><p>Vessels:</p><p>- Name: Vessel1</p><p>VesselType: FPSO</p><p>The included file contains just the data for the vessel type:</p><p># File: C:\Desktop\FPSO.yml</p><p>Length: 240</p><p>RAOResponseUnits: degrees</p><p>RAOWaveUnit: amplitude</p><p>WavesReferredToBy: period (s)</p><p># ... remainder of large file omitted ...</p><p>As well as making the main file shorter and more readable, using this approach can offer significant QA benefits.</p><p>In this example we have used a relative path and so the program will look for FPSO.yml in the same directory as the</p><p>main text data file.</p><p>w User Interface, OrcaFlex Model Files</p><p>35</p><p>A text data file saved by OrcaFlex contains some extra information:</p><p>%YAML 1.1</p><p># Program: OrcaFlex 9.3a</p><p># File: C:\Desktop\untitled.yml</p><p># Created: 12:35 on 21/07/2009</p><p># User: jamie</p><p># Machine: holly</p><p>---</p><p>General:</p><p># Statics</p><p>StaticsMethod:</p><p>Whole System statics</p><p>BuoysIncludedInStatics: Individually Specified</p><p># Dynamics</p><p>StageDuration:</p><p>- 8</p><p>- 16</p><p>TargetLogSampleInterval: 0.1</p><p># Integration</p><p>SimulationIntegrationMethod: Implicit</p><p>ImplicitConstantTimeStep: 0.1</p><p>Environment:</p><p># Seabed</p><p>SeabedType: Flat</p><p>WaterDepth: 100</p><p>SeabedModel: Linear</p><p>SeabedNormalStiffness: 100</p><p># Current</p><p>RefCurrentSpeed: 0.4</p><p>RefCurrentDirection: 180</p><p>...</p><p>The section between the --- and ... lines is the main body of the file and is known in YAML terminology as a</p><p>document. Everything else is in fact optional and can be omitted. A YAML file can contain multiple documents,</p><p>separated by --- lines but OrcaFlex has no special treatment for such multi-document files and all data is read into</p><p>a single OrcaFlex model.</p><p>The first line (%YAML 1.1) is known as the YAML directive and specifies which version of YAML the file adheres to.</p><p>The YAML directive can be omitted. The rest of the header contains a number of comments detailing the version of</p><p>OrcaFlex which created the file, the file name etc. Again, these comments can be omitted.</p><p>Ordering issues</p><p>The order in which the data appear in a text data file is very important. OrcaFlex processes the file line by line in the</p><p>order in which it appears in the file.</p><p>Any references (e.g. Lines referring to Line Types) must be ordered so that the referenced object appears before</p><p>any references to it. So Line Types appear before Lines in the file. Similarly Vessels and 3D/6D Buoys appear before</p><p>Lines, Links, Winches and Shapes so that any connection references (e.g. a Line connected to a Vessel) can be</p><p>ordered correctly.</p><p>The other ordering issue relates to inactive data. Data which are not currently available are known as inactive data.</p><p>For example, data relating to the explicit solver are inactive when the implicit solver is selected. Inactive data cannot</p><p>be specified in a text data file.</p><p>This rule has implications for the order in which data are presented in the text data file. Consider the following</p><p>example:</p><p>General:</p><p>InnerTimeStep: 0.01</p><p>SimulationIntegrationMethod: Explicit</p><p>Since the default integration method is the implicit solver the attempt to set the explicit time step</p><p>(InnerTimeStep) will fail because it is inactive data. The solution is to set the integration method before setting</p><p>the time step:</p><p>User Interface, OrcaFlex Model Files w</p><p>36</p><p>General:</p><p>SimulationIntegrationMethod: Explicit</p><p>InnerTimeStep: 0.01</p><p>This principle applies in general – you should set as soon as possible all data which influences whether other data</p><p>are active.</p><p>Automation</p><p>Text data files can easily be modified and/or generated by computer programs/scripts. This means that the text</p><p>data file format, combined with a text processing script language (e.g. Python, Perl, Ruby etc.), can form a very</p><p>effective automation tool. The OrcaFlex Spreadsheet provides a simple, yet effective, facility for automating the</p><p>production of text data files. See the Automation topic Text Data Files: Examples of setting data for examples of</p><p>setting various model data items.</p><p>Some specialist features have been included in the text data file to aid with automation tasks, as illustrated in the</p><p>following example:</p><p>BaseFile: base.dat</p><p>Riser:</p><p>ContentsDensity: 0.8</p><p>Length[1]: 180</p><p>Delete: Connector</p><p>When this text data file is loaded in OrcaFlex the program does the following:</p><p>1. Opens the OrcaFlex binary data file named base.dat, located in the same directory as the text data file.</p><p>2. Sets the contents density for the OrcaFlex Line called "Riser" to 0.8.</p><p>3. Sets the length of the first section of "Riser" to 180.</p><p>4. Deletes the object named "Connector".</p><p>The BaseFile identifier differs from IncludeFile in that it is able to load either binary or text data files</p><p>(IncludeFile only works with text data files). In addition BaseFile clears all existing data in the model before</p><p>loading the contents of the specified file. On the other hand, IncludeFile acts incrementally, starting from</p><p>whatever state the model is in when the IncludeFile identifier is encountered.</p><p>Standard text data files typically specify the entire model. The common automation task of making systematic</p><p>variations to a base case requires the ability to specify an existing object for which data modifications are to be</p><p>made. This is done using the object's name – in the example above the Riser: line performs this step.</p><p>In a similar vein it is a common requirement to modify data for certain items in a list or table without specifying the</p><p>entire table. The indexing syntax (Length[1] in the example) performs this task. Note that as for batch script files the</p><p>indices are always 1-based.</p><p>Manually edited text data files</p><p>Saving a text data file, then editing it is a good way to create a base file for automation, or to discover data names</p><p>and data structure for an object. However, please be aware that this is a one way process. OrcaFlex reads and</p><p>interprets a text data file line by line to build the model incrementally, discarding the lines once processed. When</p><p>saving a file OrcaFlex exports each object, including any default values. Consequently the save process is not the</p><p>inverse of the load process and any manual modifications to the input file will be overwritten when the file is saved</p><p>by OrcaFlex.</p><p>In the short automation example above, if the model created when this file is loaded is saved, the text data file would</p><p>contain data for all the objects imported by the BaseFile command, the full data for the line Riser and other</p><p>default data not specified in the input file.</p><p>3.2.3 Simulation Files</p><p>Results from OrcaFlex calculations (statics or dynamics) are saved to simulation files (.sim). These are binary files</p><p>containing the following sections:</p><p> The model data. This section is essentially a binary data file.</p><p> The latest calculated state (positions, loads etc.) of the model. This section allows static state results to be</p><p>retrieved and also enables partially-run dynamic simulations to be continued.</p><p>http://www.python.org/</p><p>http://www.perl.org/</p><p>http://www.ruby-lang.org/</p><p>w User Interface, Model Browser</p><p>37</p><p> The log file which contains results for a dynamic simulation. This section is not present for static state</p><p>simulation files.</p><p>Simulation files can be generated in a number of different ways:</p><p> Interactively from the main OrcaFlex window. After a calculation (statics or dynamics) has performed then a</p><p>simulation can be saved using the File | Save or File | Save As menu items.</p><p> From the batch processing form.</p><p> From Distributed OrcaFlex.</p><p> From the OrcaFlex programming interface (OrcFxAPI).</p><p>Similarly, results can be post-processed from simulation files in a number of different ways:</p><p> Interactively from the results form.</p><p> From the OrcaFlex spreadsheet.</p><p> From the OrcaFlex programming interface.</p><p>3.3 MODEL BROWSER</p><p>At any time you can use the Model Browser to see what objects you have in your model. To display the model</p><p>browser, use the model browser button or the Model | Model Browser menu item or use the keyboard shortcuts</p><p>(F6 to open the model browser).</p><p>Figure: Model Browser</p><p>User Interface, Model Browser w</p><p>38</p><p>The Model Browser consists of a list of all the objects in the model, arranged into categories according to object type.</p><p>Several symbols are used in the list of objects:</p><p>Categories can be opened, to show their contents, or closed, to simplify viewing a complex model.</p><p>Objects. Use double click to view or edit the object's data.</p><p>Locked. These objects cannot be dragged by the mouse in the 3D View.</p><p>You can navigate the list and select the object required by clicking with the mouse, or using the arrow keys and</p><p>return. If the list is longer than the window then you can either enlarge the window or use the scroll bar.</p><p>Note: More than one object can be selected in the model browser. This allows</p><p>you to perform the same</p><p>action (e.g. delete, copy, hide, show, locate) on many objects at once. To select more than one object</p><p>you use the standard Windows key presses CTRL+CLICK to add to a selection and SHIFT+CLICK to</p><p>extend a selection.</p><p>Hint: If you have all objects in the model browser selected then it can be difficult to de-select them. The</p><p>simplest way is to use CTRL+CLICK to de-select one item and then to CLICK that item again to select</p><p>it alone.</p><p>Model Browser Facilities</p><p>The model browser menus, and its pop-up menu, provide the following model management facilities. For details of</p><p>keyboard shortcuts see Keys on Model Browser.</p><p>Library</p><p>The Library menu facilities allow you to open a second data file. You can then Import objects from that second file</p><p>into the current model. You can also import using drag and drop with the mouse.</p><p>Add</p><p>Add a new object to the model.</p><p>Edit</p><p>Open the object's data form. This action can also be invoked by double-clicking an item, or by selecting it and</p><p>pressing ENTER.</p><p>Move Selected Objects</p><p>Opens the Move Selected Objects Wizard.</p><p>Rename</p><p>Rename the selected object. You can also rename by single-clicking the selected object.</p><p>Locate</p><p>Finds and highlights the object in any open 3D view windows. This is useful in complex models where many objects</p><p>are on the 3D view. The highlighting method is determined by the Locate Object Method preference.</p><p>Compare</p><p>Compares data for the two selected objects. The objects can be simple OrcaFlex objects (e.g. Vessels, Lines etc.) or</p><p>browser groups. The Compare Data configuration is used to perform the comparison.</p><p>Lock/Unlock</p><p>Lock or unlock the selected object.</p><p>Hide/Hide All/Show/Show All</p><p>Control whether the objects are drawn on 3D views.</p><p>Expand All/Collapse All</p><p>Expands or collapses all top level containers in the current browser view.</p><p>Properties</p><p>Shows the object properties form for the selected object.</p><p>w User Interface, Model Browser</p><p>39</p><p>Cut/Copy</p><p>Cut or Copy the selected object to the clipboard.</p><p>Paste</p><p>Paste an object from the clipboard into the model.</p><p>Delete</p><p>Delete the selected object from the model.</p><p>Floating, Dock Left, Dock Right</p><p>Determines whether the Model Browser is a separate, floating, top-level window or is docked inside the main</p><p>OrcaFlex window.</p><p>Reorder</p><p>You can use drag and drop with the mouse to reorder objects in the model. This is useful if you are working on the</p><p>static position of one particular line – you can drag it up to the top of the list of lines, so that it will be tackled first</p><p>when OrcaFlex does the static analysis.</p><p>Switch to Main Window</p><p>The browser's Window menu enables you to switch focus to the main form without closing the browser window. A</p><p>corresponding command on the main form's Window menu switches focus back.</p><p>3.3.1 Model Browser Views</p><p>There are 2 ways of viewing objects in the model browser: by Types or by Groups. You can switch between views</p><p>by clicking on the model browser View | View by Groups menu item, or though the popup menu.</p><p>Types View</p><p>This is the traditional model browser view. The browser has a number of folders containing objects of the same</p><p>type. For example all the lines are contained in a folder called "Lines". Objects can be reordered within a folder but</p><p>they cannot be moved to a different folder.</p><p>Groups View</p><p>This view allows you to customise how the objects are arranged in the model browser. You can add any number of</p><p>browser groups to the browser. These groups are simply folders in the browser tree. Groups can contain any</p><p>number of objects or other groups. In this way a hierarchical structure for the model can be created.</p><p>To add groups you select the Edit | Add Group menu item or use the popup menu. Groups can be renamed in the</p><p>same way as other objects. Objects can be added to a group by dragging the objects onto the group. Any number of</p><p>objects can be added to a group in one operation by first selecting the objects and then dragging them. This multiple</p><p>selection is performed using the standard Windows key presses CTRL+CLICK to add to a selection and SHIFT+CLICK to</p><p>extend a selection. Groups can be dragged into other groups and so a hierarchical structure for the model can be</p><p>created.</p><p>As well as allowing you the freedom to structure your model however you like, the Groups View allows you to</p><p>perform the same action (e.g. delete, copy, hide, show, locate) on all objects in a group. The grouping structure is</p><p>also used when cycling through data forms- clicking the Next button takes you to the next object in the groups view.</p><p>3.3.2 Move Selected Objects Wizard</p><p>This wizard allows you to move and rotate a number of objects en masse. The wizard is most useful when you select</p><p>multiple objects, a group or a number of groups or even the entire model.</p><p>To use the wizard you must first open the Model Browser and select the objects which you wish to move. Then click</p><p>Move Selected Objects on the browser's edit menu (also available from the popup menu).</p><p>Selecting objects</p><p>Before using the wizard you must select (in the model browser) the objects which you wish to move. There are a</p><p>variety of ways in which you can do this. We list a few of the more useful methods below:</p><p> Select a single object.</p><p>User Interface, Libraries w</p><p>40</p><p> Select multiple objects. You can do this in the model browser using CTRL+CLICK to add to a selection and</p><p>SHIFT+CLICK to extend a selection.</p><p> Select an object type folder. This works when the model browser is in Types View mode. For example select the</p><p>Lines folder if you wish to move all the lines in a model.</p><p> Select a group. This works when the model browser is in Groups View mode. This allows you to move all objects</p><p>in that group.</p><p> Select the entire model. This is easiest to do when the model browser is in Groups View mode. The first item in</p><p>the model browser is titled "Model". Select this item if you wish to move all objects in the model.</p><p>There is no limitation to the type of selections you can make. If you wish to move 2 groups then select both of them</p><p>(using CTRL+CLICK) and open the wizard.</p><p>Note: If your selection includes an item which contains other objects (e.g. a group or an object type</p><p>folder) then all objects contained by that item will be moved by the wizard.</p><p>Points</p><p>The wizard shows a list of the points associated with each selected object. For objects like buoys, vessels and shapes</p><p>a single point is shown. For objects like lines, links and winches with multiple connection points the list shows each</p><p>connection point for that object. The list also shows the global coordinates of each point.</p><p>For each point you have the option of including or excluding it in the move operation. This might be useful if you</p><p>wanted to move only the End A line connection points and leave the End B connection points unchanged, for</p><p>example.</p><p>Move specified by</p><p>There are 4 methods of specifying how the objects are moved.</p><p>Displacement</p><p>For this method you specify a position change (i.e. a displacement) which will be applied to all the points included in</p><p>the move operation.</p><p>Polar Displacement</p><p>This method is similar to the Displacement method. Here you specify a direction and distance which determine a</p><p>position change. This is applied to all the points included in the move operation.</p><p>New Position</p><p>Here you give a reference point and its new position. The same displacement is applied to all other points included</p><p>in the move.</p><p>Rotation</p><p>This method rotates the included points in the horizontal plane. You specify an angle of rotation and a central point</p><p>about which the rotation is performed. Note that the environment data (e.g. wave and current directions, seabed</p><p>direction etc.) is not included in the rotation.</p><p>Moving the objects</p><p>Once you have decided which objects to include in the move and how the move is specified you are ready to actually</p><p>move the objects. This is done by clicking the Move button. If you change</p><p>your mind and decide not to move the</p><p>objects then simply click the Close button.</p><p>3.4 LIBRARIES</p><p>An OrcaFlex Library is a collection of OrcaFlex objects (line types, lines, buoys etc.) stored in an ordinary OrcaFlex</p><p>data file. For example, a library may contain all the standard Line Types that you use regularly. Once such a library</p><p>file has been built you can quickly build new models using the library – this gives faster model building and can</p><p>make QA procedures safer.</p><p>To open a library file, use the Library menu on the Model Browser. Note that any OrcaFlex data file can be opened as</p><p>a library file, and this makes it easy to use the model browser to copy objects from one model to another.</p><p>w User Interface, Libraries</p><p>41</p><p>3.4.1 Using Libraries</p><p>Libraries allow you to easily import objects from one OrcaFlex model to another. To do this run OrcaFlex and open</p><p>the model browser by clicking the model browser button or the Model | Model Browser menu item, or pressing</p><p>F2. The model browser should look like:</p><p>Now you open your file as a library. To do this click the open button on the model browser and select your data</p><p>file. Now the model browser will look like:</p><p>User Interface, Libraries w</p><p>42</p><p>We are now going to copy some objects from the right hand pane to the left hand pane. To do so select the required</p><p>line types and click the import button . As an alternative to the import button the objects can be dragged from</p><p>the right hand pane to the left hand pane or the Library | Import menu item can be used.</p><p>Note that you can select a number of objects and import them all in one go. You do this by using the standard</p><p>Windows key presses CTRL+CLICK to add to a selection and SHIFT+CLICK to extend a selection. If you do this the</p><p>library will look like:</p><p>w User Interface, Libraries</p><p>43</p><p>Once you have imported the required objects you can close the library by selecting the Library | Close menu item</p><p>on the model browser. Now the model browser looks like:</p><p>User Interface, Menus w</p><p>44</p><p>Here are some other points about using library files:</p><p> Because library files are simply ordinary OrcaFlex data files, you can temporarily treat any OrcaFlex data file as</p><p>a library. This allows you to import objects from one OrcaFlex data file to another.</p><p> You can re-size the model browser by dragging its border. You can also control the relative sizes of its two</p><p>panes, by dragging the right border of the left pane.</p><p> You can view, but not edit, the data for a library model object, by double clicking it in the Model Browser or by</p><p>selecting it and using the pop-up menu.</p><p> When an object is imported from a library, the current model may already have an object of that name. In this</p><p>case OrcaFlex automatically gives the object a new name based on the old name.</p><p>3.4.2 Building a Library</p><p>A library file is simply an OrcaFlex data file – you can use any OrcaFlex data file as a library. In practice it is most</p><p>convenient to put your commonly used OrcaFlex objects into files designated as OrcaFlex library files.</p><p>You build a library file in the same way as you build a standard OrcaFlex data file. Starting with a blank model you</p><p>can add objects in the usual way and set their data. Typically, however, you would want to reuse objects that had</p><p>previously been created and used for a project.</p><p>To do this you would open the model browser and load your project data file as a library using the open button</p><p>on the model browser. Then you import the required objects as described in Using Libraries. This procedure can be</p><p>repeated with a number of different data files until you have all the objects you wish to keep in the library. Then you</p><p>should close the model browser and save the data file by clicking the button on the main OrcaFlex form. This</p><p>data file can now be used as a library.</p><p>Notes: Because they are OrcaFlex models, libraries contain General and Environment data, but these</p><p>would not usually be used, except perhaps for the General data Comment field, which can act as a</p><p>title for the library.</p><p>Because the library file is just an ordinary OrcaFlex data file, it can also be opened using File |</p><p>Open. This allows you to edit the data of the objects in the library.</p><p>You can set up as many library files as you wish. For example you might have separate libraries for Line Types,</p><p>Attachment Types, Vessel Types, Variable Data Sources etc., or you may choose to use just one library for</p><p>everything. The model browser's Library menu contains a list of the most recently used libraries.</p><p>3.5 MENUS</p><p>OrcaFlex has the following menus:</p><p> The File menu has the file opening and saving commands, plus commands for printing or exporting data or</p><p>results and managing libraries.</p><p> The Edit menu has data and object editing facilities.</p><p> The Model menu gives access to the model building facilities.</p><p> The Calculation menu provides commands for starting and stopping analyses, including batch processing.</p><p> The View menu provides view control.</p><p> The Replay menu provides replay control.</p><p> The Graph menu gives you access to facilities related to the currently active graph window.</p><p> The Results menu leads to the results facilities.</p><p> The Tools menu allows you adjust preferences and to lock or unlock objects.</p><p> The Workspace menu allows you to save and restore collections of view, graph and spreadsheet windows.</p><p> The Window menu gives access to the various windows that are available, and allows you to adjust the layout of</p><p>your windows.</p><p> The Help menu leads to the various help documentation that is available.</p><p>w User Interface, Menus</p><p>45</p><p>3.5.1 File Menu</p><p>New</p><p>Deletes all objects from the model and resets data to default values.</p><p>Open</p><p>Open an OrcaFlex file – either a data file (.dat or .yml) or a simulation file (.sim).</p><p>You can also open an OrcaFlex file by dragging and dropping it onto the OrcaFlex window. For example if you have</p><p>Windows Explorer running in one window and OrcaFlex running in another then you can ask OrcaFlex to open a file</p><p>by simply dragging it from Explorer and dropping it over the OrcaFlex window.</p><p>If you open a data file then OrcaFlex reads in the data, whereas if you select a simulation file then OrcaFlex reads in</p><p>both the data and the simulation results. To read just the data from a simulation file, you can use the Open Data</p><p>menu item.</p><p>Save</p><p>Save an OrcaFlex file – either a data file (.dat or .yml) or a simulation file (.sim) – to the currently selected file name.</p><p>If a file of that name already exists then it is overwritten.</p><p>If calculation results (either statics or dynamics) are available then a simulation file will be saved. Otherwise a data</p><p>file will be saved.</p><p>Note: You cannot save a dynamic simulation while it is running – you must pause the simulation first.</p><p>Save As</p><p>This is the same as Save but allows you to specify the file name to save to. If a file of that name already exists then</p><p>you are asked whether to overwrite the file.</p><p>When saving data you can choose either the binary file format (.dat) or the text file format (.yml) from the Save as</p><p>type drop down list.</p><p>Open Data</p><p>Read the data from an existing data file or simulation file, replacing the existing model. If a simulation file is</p><p>specified then OrcaFlex reads just the data from it, ignoring the simulation results in the file.</p><p>Save Data</p><p>Save the data to the currently selected file name, using extension .dat or .yml. If a file of that name already exists</p><p>then it is overwritten.</p><p>Save Data As</p><p>This is the same as Save Data but allows you to specify the file name to save to. If a file of that name already exists</p><p>then you are asked whether to overwrite the file.</p><p>You can choose either the binary file format (.dat) or the text file format (.yml) from the Save as type drop down list.</p><p>Compare Data</p><p>Compares the data of two OrcaFlex models. See Comparing Data for details.</p><p>Properties</p><p>Displays the system file properties dialog</p><p>for the current file. This is mainly intended to make it easier to find the full</p><p>path for files with long names.</p><p>Submit to Distributed OrcaFlex</p><p>Submit the current file for processing by Distributed OrcaFlex. For this option to be available, either the Distributed</p><p>OrcaFlex Viewer or Client must also be installed on the machine.</p><p>Selected Printer</p><p>Allows you to change the selected printer.</p><p>http://www.orcina.com/Support/DistributedOrcaFlex</p><p>User Interface, Menus w</p><p>46</p><p>Printer Setup</p><p>Calls up the Printer Setup dialogue window. This standard Windows dialogue is used to select which printer to use,</p><p>and allows you to control the way that it is used – the details vary from printer to printer, and depend on the printer</p><p>manufacturer's device driver currently installed. Please refer to the manuals for your printer as well as the</p><p>Microsoft documentation.</p><p>Print</p><p>Display the Print form, allowing you to print 3D Views, Graphs, Spreadsheets or Text Windows. See Printing.</p><p>Most Recent Files</p><p>List of the most recently used files. Selecting an item on the list causes the file to be opened.</p><p>Exit</p><p>Close OrcaFlex.</p><p>3.5.2 Edit Menu</p><p>Undo Drag</p><p>Undo the most recent drag. This is useful if you accidentally drag an object.</p><p>Cut</p><p>Copies the current selection to the clipboard and then deletes it.</p><p>Copy</p><p>If there is a currently selected object (see Selecting Objects), then that object is copied to the clipboard. You can then</p><p>use Edit | Paste to create duplicate copies of the object. The data for the object is copied to the clipboard in text form,</p><p>from where it can be pasted into a word processor document.</p><p>Note: After pasting into a word processor, you will probably need to put the text into a fixed space font</p><p>since much of the data is in tables.</p><p>If there is no currently selected object then the currently selected 3D view, text window, graph or spreadsheet is</p><p>copied to the clipboard.</p><p>Paste</p><p>Insert object from clipboard. This can be used to duplicate an object several times within the model. After selecting</p><p>Paste, the object is inserted at the next mouse CLICK position in a 3D view.</p><p>If the current window is a Spreadsheet then the contents of the clipboard are pasted into the spreadsheet.</p><p>Delete</p><p>If the active window is a 3D View then the currently selected object is deleted. Before the object is deleted, any</p><p>connected objects are disconnected, and any graphs associated with the object are closed.</p><p>If the active window is a Spreadsheet then the selected cells are cleared.</p><p>Select All</p><p>Selects all the cells in a Spreadsheet.</p><p>3.5.3 Model Menu</p><p>Model Browser</p><p>Toggles the visibility of the Model Browser.</p><p>w User Interface, Menus</p><p>47</p><p>New Vessel</p><p>New Line</p><p>New 6D Buoy</p><p>New 3D Buoy</p><p>New Winch</p><p>New Link</p><p>New Shape</p><p>Create new objects. The mouse cursor changes to the New Object symbol . The object is placed at the position of</p><p>the next mouse CLICK within a 3D View. A three dimensional position is generated by finding the point where the</p><p>mouse CLICK position falls on a plane normal to the view direction and passing through the View Centre. Vessels are</p><p>always placed initially at the sea surface.</p><p>Show Connections Report</p><p>Displays a spreadsheet containing information about all object connections in the model.</p><p>Delete Unused Types</p><p>Deletes any types (e.g. Line Types, Clump Types etc.) that are not in use. This is sometimes useful to simplify a data</p><p>file, or to find out which types are in use.</p><p>Delete Unused Variable Data Sources</p><p>Deletes any variable data sources that are not in use. This is sometimes useful to simplify a data file, or to find out</p><p>which variable data sources are in use.</p><p>Use Calculated Positions</p><p>This menu item is available after a successful static iteration or when the simulation is finished or paused.</p><p>If the model is in the statics complete state then clicking the menu item sets the initial positions of buoys, vessels</p><p>and free line ends to be the calculated static positions. This can be desirable when setting up a model, since the</p><p>positions found are likely to be good estimates for the next statics calculation.</p><p>If the model is in the simulation paused or stopped state, then clicking the menu item sets the initial positions of</p><p>buoys and free line ends to be the latest positions in the simulation. This is useful when OrcaFlex statics fails to find</p><p>an equilibrium configuration. In such cases you can use dynamics with no wave motion to find the static equilibrium</p><p>position and then click Use Calculated Positions.</p><p>If a replay is active then clicking the menu item sets the initial positions of buoys and free line ends to be the</p><p>positions at the latest replay time.</p><p>Use Specified Starting Shape for Lines</p><p>This menu item is an extension of Use Calculated Positions. As well as setting the initial positions of buoys, vessels</p><p>and free line ends it modifies data for all Lines in the following way:</p><p>1. The Step 1 Statics Method is set to User Specified.</p><p>2. The User Specified Starting Shape data are set to the calculated node positions. As described above these</p><p>positions are either the results of a static calculation or the results of a dynamic simulation.</p><p>Use Static Line End Orientations</p><p>This menu item is only available after a successful static analysis. Clicking the menu item sets the line end</p><p>orientation data, for all line ends in the model that have zero connection stiffness, to the orientations found in the</p><p>static analysis. This is done as follows.</p><p> For any line end with zero bend connection stiffness, the end azimuth and end declination will be set to the</p><p>azimuth and declination of the end node, as found by the static analysis.</p><p>User Interface, Menus w</p><p>48</p><p> If the line includes torsion and the line end connection twist stiffness is zero, then the end gamma will be set to</p><p>the gamma of the end node, as found by the static analysis.</p><p>This action can be useful if you want to set the line end orientation to that which gives zero end moments when the</p><p>line is in its static position. To do this first set the end connection stiffness values to zero, then run the static analysis</p><p>and then click the Use Static Line End Orientations menu item. You can then set the end connection stiffness to</p><p>their actual values.</p><p>3.5.4 Calculation Menu</p><p>Single Statics</p><p>Start the single statics calculation (see Static Analysis). Progress and any error messages that occur are reported in</p><p>the Statics Progress Window, which is shown as a minimised window icon. The statics calculation can be</p><p>interrupted by CLICKING the Reset button.</p><p>Multiple Statics</p><p>Starts the multiple offset statics calculation (see Multiple Statics). Progress and any error messages that occur are</p><p>reported in the Statics Progress Window, which is shown as a minimised window icon. The statics calculation can be</p><p>interrupted by CLICKING the Reset button.</p><p>Run Dynamic Simulation</p><p>Start a dynamic simulation (see Dynamic Analysis). If necessary, OrcaFlex will automatically do a statics calculation</p><p>first. During the simulation, the Status Bar shows the current simulation time and an estimate of the time that the</p><p>simulation will take, and all 3D View windows and Graphs are updated at regular intervals.</p><p>Pause Dynamic Simulation</p><p>Pause the simulation. To save the results of a part-run simulation you need to pause it first. The simulation can be</p><p>restarted by CLICKING the Run button.</p><p>Extend Dynamic Simulation</p><p>This facility is only available when the current simulation is either paused or completed. It adds another stage to the</p><p>current simulation, without having to reset. You are asked to specify the length of the new stage. You can then</p><p>continue the simulation, without having to restart it from scratch. This is particularly useful if you have a simulation</p><p>that has not been run for long enough.</p><p>Note that data for the new stage, e.g. for winch control and vessel prescribed motion, are initially set to be the same</p><p>as for the previous stage.</p><p>However, the data for the new stage can be edited because the new stage has not yet</p><p>started.</p><p>Reset</p><p>Reset the model, discarding any existing results. The model can then be edited or a new model loaded.</p><p>View Warnings</p><p>Displays a window allowing you to review all warnings displayed by OrcaFlex during a calculation (statics or</p><p>dynamics).</p><p>This feature is particularly useful for simulations run in batch mode or by Distributed OrcaFlex. In these</p><p>circumstances warnings are not displayed since to do so would require user intervention.</p><p>Line Setup Wizard</p><p>Opens the Line Setup Wizard. The wizard is only available when the current simulation is in Reset state.</p><p>Wave Scatter Conversion</p><p>Opens the Wave Scatter Conversion form. This facility converts a scatter table of sea states to a scatter table of</p><p>regular (i.e. individual) waves.</p><p>Batch Processing</p><p>Run a batch of analyses automatically while the program is unattended. See Batch Processing for details.</p><p>w User Interface, Menus</p><p>49</p><p>3.5.5 View Menu</p><p>Change Graphics Mode</p><p>Toggles the graphics mode between wire frame and shaded.</p><p>Edit View Parameters</p><p>Adjust the View Parameters for the active 3D View.</p><p>Rotate Up / Down / Left / Right</p><p>Change the view direction, for the active 3D View, by the view rotation increment.</p><p>Plan</p><p>Set the active 3D View to a plan view (Elevation = 90°).</p><p>Elevation</p><p>Set the active 3D view to an elevation view (Elevation = 0°).</p><p>Rotate 90 / Rotate -90</p><p>Increase (or decrease) the view azimuth by 90°, for the active 3D view.</p><p>Zoom In / Zoom Out</p><p>Click the zoom button to zoom in (decrease view size) or SHIFT+CLICK it to zoom out (increase view size).</p><p>Reset to Default View</p><p>Set the view parameters for the active 3D View to be the default view of the model.</p><p>Set as Default View</p><p>Set the default view of the model to be the view parameters of the active 3D View.</p><p>Show Entire Model</p><p>Set the view parameters for the active 3D View so that the entire model will be displayed.</p><p>Axes</p><p>This submenu gives you control of the 3D View Axes Preferences.</p><p>3.5.6 Replay Menu</p><p>Edit Replay Parameters</p><p>Adjust the Replay Parameters, such as the period of simulation to replay, the time interval between frames, the</p><p>replay speed etc. For more information see Replays.</p><p>Start / Stop Replay</p><p>Starts or stops the replay.</p><p>Step Replay Forwards, Step Replay Backwards</p><p>Step the replay forwards or backwards one frame at a time. Click the button to step forwards; CLICK with SHIFT held</p><p>down to step backwards.</p><p>Replay Faster / Slower</p><p>Increase or decrease the replay frame rate (replay speed).</p><p>Export Video</p><p>Exports the replay as a video clip in AVI file format. See Replays for more details.</p><p>User Interface, Menus w</p><p>50</p><p>3.5.7 Graph Menu</p><p>Use Default Ranges</p><p>Sets the graph axes to their original ranges</p><p>Values</p><p>Displays a spreadsheet containing the numerical values on which the graph is based.</p><p>Spectral Density (only available for time history graphs)</p><p>Opens a new spectral density graph.</p><p>Empirical Cumulative Distribution (only available for time history graphs)</p><p>Opens a new empirical cumulative distribution graph.</p><p>Rainflow half-cycle Empirical Cumulative Distribution (only available for time history graphs)</p><p>Opens a new rainflow half-cycle empirical cumulative distribution graph.</p><p>Properties</p><p>Opens the graph properties form (which can also be opened by double clicking the graph).</p><p>3.5.8 Results Menu</p><p>Select Results</p><p>Display the results form which allows you to choose from the currently available selection of graphs and results</p><p>tables. Graphs such as Time Histories, XY Graphs and Range Graphs may be created before a simulation has been</p><p>run, thus allowing you to watch the variables during a simulation.</p><p>Fatigue Analysis</p><p>Opens the Fatigue Analysis form.</p><p>Modal Analysis</p><p>Opens the Modal Analysis form.</p><p>Report Vessel Response</p><p>Opens the Vessel Response form.</p><p>3.5.9 Tools Menu</p><p>Lock / Unlock Selected Object</p><p>Locking an object prevents it from being accidentally dragged or connected using the mouse on 3D views, for</p><p>example if you nudge the mouse slightly while trying to DOUBLE CLICK. Lock / Unlock Selected Object toggles the lock</p><p>on the currently selected object. If the lock is on, it will be switched off. If the lock is off, then it will be switched on.</p><p>Locked Objects may still have their positions edited in the data Edit Forms. The status of the object locks is shown</p><p>by symbols in the Model Browser.</p><p>Lock / Unlock All Objects</p><p>Locks or unlocks all objects in the model.</p><p>Set Thread Count</p><p>Allows you to change the number of execution threads used by OrcaFlex for parallel processing.</p><p>Calculate Speed Index</p><p>The Speed Index is an approximate measure of how quickly a machine can perform OrcaFlex simulations. Larger</p><p>values correspond to faster machines. The Speed Index is also reported by Distributed OrcaFlex.</p><p>The Speed Index is calculated by performing a series of floating point calculations that are representative of the</p><p>calculations performed by OrcaFlex itself. The value reported is meant only to give an estimate of the relative</p><p>performance of similar machines. It is always preferable, if possible, to compare actual OrcaFlex simulation run</p><p>times for models representative of your typical use.</p><p>w User Interface, Menus</p><p>51</p><p>Preferences</p><p>Allows you to control various program settings so that you can customise the program to the way you prefer to</p><p>work. See Preferences.</p><p>3.5.10 Workspace Menu</p><p>Open Workspace</p><p>Opens a previously saved workspace file and restores the window layout described in that workspace file.</p><p>Save Workspace</p><p>Save the current window layout to a workspace file.</p><p>Preserve axes ranges</p><p>If this option is checked then graph axes ranges will be written to the workspace file. When the workspace is</p><p>subsequently opened, those axes ranges will be restored.</p><p>If this option is not checked then graph axes ranges are not written to the workspace file. When the workspace is</p><p>subsequently opened, default axes ranges are chosen based on the extent of the curves shown in the graph.</p><p>Make default for this file, Make default for this folder</p><p>Makes the current window layout the default workspace for the current simulation file or for the current folder,</p><p>respectively. The default workspace for a simulation file will be restored whenever you open that file. The default</p><p>workspace for a folder will be restored whenever you open any simulation file in that folder.</p><p>If a default workspace exists for a both a file and the folder containing the file, then the default for the file is used.</p><p>Use file default, Use folder default</p><p>Applies the default workspace to the current model. This is useful if you have changed the window layout and wish</p><p>to restore the default workspace layout without re-loading the model.</p><p>Remove file default, Remove folder default</p><p>Deletes the default workspace.</p><p>Most Recent Files</p><p>List of the most recently saved workspaces in the directory which contains the current model. Selecting an item on</p><p>the list causes the workspace to be loaded.</p><p>3.5.11 Window Menu</p><p>Add 3D View</p><p>Add another 3D View Window. Having multiple views on screen allows you to watch different parts of the system</p><p>simultaneously, or to see different views at the same time (for example a plan and an elevation).</p><p>Tile Vertical, Tile Horizontal</p><p>Arranges all the windows (3D View, graph or spreadsheet) so that they fill the main window area and fit side by side</p><p>without overlapping. The program automatically tiles windows every time a new window is created or deleted.</p><p>Switch to Model Browser</p><p>This command, and the corresponding command on the model browser's Window menu, enable you to switch focus</p><p>between the main form and the model browser window.</p><p>Statics Progress</p><p>Displays the Statics Progress Window.</p><p>External Function Output</p><p>Displays a window containing the diagnostics text produced by external functions.</p><p>Window List</p><p>This is a list of all currently</p><p>open windows. If a window is hidden under others it can be selected easily from this list.</p><p>User Interface, 3D Views w</p><p>52</p><p>3.5.12 Help Menu</p><p>OrcaFlex Help</p><p>Opens the OrcaFlex on-line help system.</p><p>What's New</p><p>Gives a list of recent improvements and alterations to OrcaFlex.</p><p>Tutorial</p><p>Opens the help file at the start of the OrcaFlex tutorial.</p><p>Examples</p><p>Opens the help file at the introduction to the OrcaFlex Examples topics.</p><p>Keyboard Shortcuts</p><p>Lists the keyboard shortcuts used by OrcaFlex.</p><p>Orcina Home Page</p><p>Opens the Orcina homepage (www.orcina.com).</p><p>About</p><p>Displays a window giving the program version, details about Orcina Ltd and various other miscellaneous</p><p>information.</p><p>3.6 3D VIEWS</p><p>3D Views are windows showing a spatial representation of the model. Two distinct types of 3D View are available:</p><p>wire frame shows an isometric projection of the model; shaded draws the model as solid objects with lighting,</p><p>shading, perspective and hidden line removal.</p><p>Figure: A wire frame 3D View (left) alongside a shaded 3D View (right)</p><p>http://www.orcina.com/</p><p>w User Interface, 3D Views</p><p>53</p><p>3D View windows may be rotated, zoomed and panned to allow any aspect of the system to be viewed. The view is</p><p>controlled by a number of View parameters – see View Parameters – and the caption of a 3D View window shows</p><p>the current View Azimuth and View Elevation values, while a scale bar in the view indicates the current View Size.</p><p>Multiple view windows may be placed side-by-side so that you can view different parts of the system</p><p>simultaneously or view from different angles (for example a plan and elevation view). This allows you to build non-</p><p>in-plane models on screen with the mouse. Further 3D View windows are added by using the Window | Add 3D</p><p>View menu item or by CLICKING on the Add 3D View button on the tool bar. Windows may be arranged by dragging</p><p>their borders or using the Window | Tile Vertical/Horizontal menu items. 3D Views may be closed by CLICKING the</p><p>cross at the top right-hand corner.</p><p>The objects in a 3D view are "live" in the sense that you can use the mouse pointer to select objects, drag them</p><p>around in the view and make connections between objects. See Selecting Objects, Creating and Destroying Objects,</p><p>Dragging Objects, Object Connections, for details. If you DOUBLE CLICK on an object then the data form for that object</p><p>appears, so that you can examine or edit its data.</p><p>Note: When using the shaded view objects cannot be selected, dragged etc. For this reason, the wire</p><p>frame view is most useful when building your model.</p><p>After running a simulation, or loading a simulation file, a dynamic replay (animation) can be shown in one or more</p><p>3D View windows. A replay shows a sequence of snapshots of the model taken at specified intervals throughout part</p><p>or all of the simulation. Replays may be played in just one 3D View window, or in all of them simultaneously – see</p><p>Preferences.</p><p>Finally, 3D Views may be printed by selecting the view desired and using the print menu. Also, the picture may be</p><p>exported to a file or the windows clipboard.</p><p>Measuring Tape Tool (only available in wire frame mode)</p><p>You can measure distance on a 3D view using the measuring tape tool. Hold down the SHIFT and CTRL keys and then</p><p>drag a line between any two points – the distance between them is displayed on the status bar. Note that this is the</p><p>distance in the plane of the 3D view.</p><p>3.6.1 View Parameters</p><p>The view shown in a 3D view window is determined by the following parameters, which can be adjusted using the</p><p>view control buttons or the Edit View Parameters item on the View menu.</p><p>Relative To</p><p>The view parameters can be specified relative to Global or relative to any Vessel, 6D Buoy or Shape object in the</p><p>model. Relative to Global gives the view from a fixed camera position. Relative to an object gives the view from a</p><p>camera that moves with that object. This can be useful when modelling systems such as towed cases, where you</p><p>want a view that tracks along with the overall movement of the model.</p><p>Size</p><p>The diameter of the view area. It equals the distance represented by the smaller of the 2 sides of the view window.</p><p>This parameter must be greater than zero.</p><p>Example: If the window on screen is wider than it is high, and View Size = 100.0 then an object 100 units</p><p>high would just fill the height of the window.</p><p>Centre</p><p>Defines the coordinates of the point that is shown at the centre of the window. This may be in global or relative</p><p>coordinates.</p><p>Azimuth, Elevation and Gamma</p><p>These determine the direction (from the view centre) from which the model is being viewed and the rotation about</p><p>this direction. The azimuth angle is measured from the x direction towards the y direction of the object we are</p><p>relative to. The elevation angle is then measured upwards (downwards for negative elevation angles) from there.</p><p>The view shown is that seen when looking from this direction, i.e. by a viewer who is in that direction from the view</p><p>centre. The Gamma angle rotates about this view direction.</p><p>Example: View Elevation +90° means looking in plan view from above, and View Elevation = 0°, View</p><p>Azimuth = 270° (or -90°) means a standard elevation view, looking along the Y axis.</p><p>User Interface, 3D Views w</p><p>54</p><p>Window Size</p><p>You can adjust the size of a 3D view window either by dragging the window border, or by setting its window size on</p><p>the view parameters form. The latter is sometimes useful when exporting a view or exporting a replay video, since it</p><p>makes it easier to export multiple files and produce videos with identical dimensions.</p><p>Graphics Mode</p><p>Can be either of the following options:</p><p> Wire frame: the model is represented using a wire frame, isometric projection.</p><p> Shaded: the model is represented as solid objects with lighting, shading, perspective and hidden line removal.</p><p>Default View</p><p>Each model has its own default view parameters that are saved with the model data. Whenever a new 3D view is</p><p>created, it starts with this default view. You can set an existing 3D view to the default view by using the Reset to</p><p>Default View command (on the view menu or pop-up menu).</p><p>To set the default view parameters, first set up a 3D View to the default view that you want and then use the Set as</p><p>Default View command (on the view menu or pop-up menu). As an alternative you can use the calculated based on</p><p>the model extent option which results in a default view that is sized so that the entire model will be displayed.</p><p>3.6.2 View Control</p><p>You can adjust the view in a 3D view window using the view control buttons:</p><p>Button Menu Item Shortcut Action</p><p>View | Rotate Up CTRL+ALT+↑ Increase view elevation</p><p>+ SHIFT</p><p>View | Rotate Down CTRL+ALT+↓ Decrease view elevation</p><p>View | Rotate Right CTRL+ALT+→ Increase view azimuth</p><p>+ SHIFT</p><p>View | Rotate Left CTRL+ALT+← Decrease view azimuth</p><p>View | Zoom In CTRL+I Zoom in</p><p>+ SHIFT</p><p>View | Zoom Out SHIFT+CTRL+I Zoom out</p><p>View | Change Graphics Mode CTRL+G Changes graphics mode</p><p>View | Edit View Parameters CTRL+W Edit View Parameters</p><p>You can also use the mouse wheel button to change view. Turn the wheel to scroll the 3D view up and down. Turn it</p><p>with the CTRL key held down to zoom in or out on the location at which the mouse is currently pointing.</p><p>For more precise control you can set the view parameters explicitly using the View Parameters form.</p><p>Finally, 3D views can also be controlled using the View menu and various shortcut keys – see Mouse and Keyboard</p><p>Actions and Navigating in 3D Views.</p><p>3.6.3 Navigating in 3D Views</p><p>Moving</p><p>Moving in 3D Views can be achieved by a variety of means:</p><p> Drag the 3D View with the SHIFT key held down. We call this direct manipulation of the view centre panning.</p><p> Use the scroll bars on the 3D View.</p><p> Use the cursor keys ↑ ↓ ← →. Use these cursor keys with the CTRL key held down to effect larger shifts.</p><p> Move up and down with the PGUP and PGDN keys.</p><p> Edit</p><p>the View Centre in the View Parameters form.</p><p>Rotating</p><p>Rotating in 3D Views can be achieved by a variety of means:</p><p>w User Interface, 3D Views</p><p>55</p><p> Drag the 3D View with the CTRL key held down. For shaded views only you can rotate about the viewer position</p><p>(as opposed to rotating about the view centre) by holding down the ALT key (as well as the CTRL key) whilst</p><p>dragging.</p><p> Use the rotate buttons . Pressing these with the SHIFT key held reverses the rotation.</p><p> Use the Rotate Up, Rotate Down, Rotate Left or Rotate Right menu items or their shortcut keys CTRL+ALT+ ↑ ↓ ←</p><p>→.</p><p> Use the Plan, Elevation, Rotate 90 or Rotate -90 menu items or their shortcut keys CTRL+P, CTRL+E, CTRL+Q and</p><p>SHIFT+CTRL+Q.</p><p> Edit the View Azimuth and View Elevation in the view parameters form.</p><p>Zooming</p><p>You can zoom into and out of 3D Views by using the zoom button , the zoom menu items and the shortcut keys</p><p>CTRL+I and SHIFT+CTRL+I. In addition, you can zoom in or out using the mouse wheel button with the CTRL key held</p><p>down.</p><p>The following methods of zooming are only available in wire frame 3D Views.</p><p>Also you can zoom in on a particular region of interest in a 3D view by defining a rectangle around it on screen using</p><p>the mouse. To do this, hold the ALT key down, place the mouse in one corner of the desired rectangle and press</p><p>down the left mouse button while dragging the mouse to the opposite corner. When you release, the region selected</p><p>will be expanded to fill the window.</p><p>To zoom out, repeat the operation holding down the SHIFT and ALT keys – the region shown in the window will</p><p>shrink to fit into the rectangle drawn.</p><p>You can also zoom in and out by a fixed amount, keeping the same view centre, by using ALT+CLICK and</p><p>ALT+SHIFT+CLICK.</p><p>3.6.4 Shaded Graphics</p><p>The shaded graphics mode renders the model as solid objects with lighting, shading, perspective and hidden line</p><p>removal.</p><p>User Interface, 3D Views w</p><p>56</p><p>Figure: Shaded graphics</p><p>Using the Shaded Graphics mode</p><p>To a large extent there is no extra work required to build a model for the shaded graphics mode. You are able to</p><p>build a model or take an existing model designed using the wire frame mode and simply change to the shaded</p><p>graphics mode to see a high quality shaded rendering of your model. There are a number of things you can do to</p><p>improve your experience with the shaded graphics mode as described below.</p><p>Translucency</p><p>The Sea Surface and Seabed are drawn as textured surfaces. If there are objects on the other side of these surfaces</p><p>then they can be obscured. These surfaces are drawn with a user-specified amount of translucency which allows you</p><p>to compensate for this.</p><p>Importing 3D models</p><p>Objects like Lines are straightforward to draw. OrcaFlex uses the Line Type contact diameter to determine the</p><p>thickness of each segment of the Line.</p><p>Objects like Vessels present more difficulties. OrcaFlex by default will draw a solid, filled-in shape based on the wire</p><p>frame data you have specified. While this can be sufficient you may prefer something less simplistic. Alternatively</p><p>you may import a more detailed 3D model, e.g. the turret moored FPSO above. You can import 3D models for 6D</p><p>Buoys, Wings and Shapes as well as for Vessels.</p><p>We have provided a very basic selection of generic models which you are free to use. There are models of an FPSO, a</p><p>turret moored FPSO, an installation vessel, a semisub and a subsea template. For information on generating and</p><p>importing 3D models specific to your project please refer to www.orcina.com/Support/ShadedGraphics.</p><p>Viewer Position</p><p>Because the shaded graphics mode uses perspective it requires the concept of the viewer position as well as the</p><p>viewer centre. The isometric wire frame view has no such requirement. OrcaFlex defines the viewer position to be in</p><p>http://www.orcina.com/Support/ShadedGraphics</p><p>w User Interface, 3D Views</p><p>57</p><p>a line in the view direction (defined by the view azimuth and view elevation) at a distance of view size * 1.5 from the</p><p>view centre. It is possible to rotate the view around both the view centre and around the viewer position.</p><p>Video export</p><p>Just as for wire frame views OrcaFlex can export video files of a replays in shaded views. When producing videos it</p><p>is very important to use compression, otherwise the video file size becomes unreasonably large. The software that</p><p>performs this compression is called a codec.</p><p>For wire frame replays OrcaFlex uses a built-in codec called run-length encoding. This codec is not suitable for</p><p>shaded replays and in fact there is no suitable built-in codec in Windows. We would recommend using an MPEG-4</p><p>codec of which many are available. In our experience the freely available XVID codec performs very well. The XVID</p><p>codec can be downloaded from www.orcina.com/Support/ShadedGraphics.</p><p>Should you wish to use a different codec you can select this from the Preferences form.</p><p>Hardware Requirements</p><p>The shaded graphics mode does require the presence of a DirectX 9 compatible graphics card. In our experience the</p><p>most important factor to consider when choosing a card to work with shaded graphics is the amount of memory. We</p><p>would recommend using a card with 256MB or more.</p><p>It is also important to make sure that your computer's graphics settings specify a colour mode of 16 bits (65536</p><p>colours) or better.</p><p>Notes: If your machine's graphics capabilities are insufficient then the shaded graphics mode may fail to</p><p>function properly or indeed fail to function at all. For example, low quality, blocky images usually</p><p>indicate a graphics card with insufficient memory. This problem can also manifest itself by failure</p><p>to draw the sky which appears plain white.</p><p>For best results you should centre your model close to the global origin. The Move Selected Objects</p><p>facility can help you do this.</p><p>3.6.5 How Objects are Drawn</p><p>Each object in the model is drawn as a series of lines using the Pen Colour, Line Width and Style (solid, dashed etc.)</p><p>defined in the drawing data for that object. You can change the pen colours etc. used at any time by editing the</p><p>drawing data for that object. To change the pen colour, select and CLICK the colour button on the data form and then</p><p>CLICK on the new colour wanted.</p><p>You can also exclude (or include) individual objects from the 3D view, by opening the model browser, selecting the</p><p>object and then using the Hide (or Show) command on the browser's Edit or pop-up menu.</p><p>Notes: In Windows, a line width of zero does not mean "don't draw" – it means draw with the minimum</p><p>line width. To suppress drawing either set the line style to null (the blank style at the bottom of the</p><p>drop down list) or else hide the object.</p><p>On some machines the display driver cannot draw the dashed or dotted pen styles and instead</p><p>draws nothing. So on such machines only the solid and blank pen styles work.</p><p>Wire Frame Drawing</p><p>For wire frame views the various objects are drawn as follows:</p><p> The various coordinate systems can be drawn as small triplets of lines showing their origin and the orientation</p><p>of their axes. The wave, current and wind directions can be drawn as arrows in the top right hand corner of 3D</p><p>views. You can control both what is drawn (see 3D View Drawing Preferences) and the drawing data used.</p><p> The Seabed is drawn as a grid using the seabed pen.</p><p> The Sea Surface is drawn as a grid or as a single line. This is controlled by the user's choice of Surface Type as</p><p>specified on the drawing page on the Environment data form. If the Surface Type is set to Single Line then one</p><p>line is drawn, aligned in the wave direction. If the Surface Type is set to Grid then a grid of lines is drawn. This</p><p>line or grid is drawn using the sea surface pen.</p><p> Shapes are drawn either as wire frames (Blocks, Cylinders and Curved Plates) or as a grid (Planes). As well as</p><p>controlling the pen colour, width and style, for shapes you can also control the number of lines used to draw the</p><p>shape.</p><p>http://www.orcina.com/Support/ShadedGraphics</p><p>User Interface, 3D Views w</p><p>58</p><p> Vessels are drawn as a wire frame of edges and vertices defined by the user on the Vessel and Vessel Types data</p><p>forms.</p><p> 3D Buoys are drawn as a single vertical line of length equal to the height of the buoy.</p><p> 6D Buoys are drawn as a wire frame of edges and vertices. For Lumped Buoys, the vertices and edges are</p><p>defined by the user on the buoy data form. For Spar Buoys and Towed Fish the vertices and edges are</p><p>automatically generated by OrcaFlex to represent the stack of cylinders that make up the buoy. As an option</p><p>Spar Buoys and Towed Fish can be drawn as a stack of circular cylinders – this is the default setting.</p><p> Wings are drawn as rectangles in either the 6D Buoy pen or the Wing Type pen as determined in the Wing Type</p><p>data.</p><p> Lines are drawn as a series of straight lines, one for each segment, joining points drawn at each node. Separate</p><p>pens are used for the segments and nodes, so you can, for example, increase the pen width used for the nodes to</p><p>make them more visible. There is also, on the Line Data form, a choice of which pen to use to draw the segments.</p><p> Clumps are drawn as a thin vertical bar.</p><p> Drag Chains are drawn using the colour and line style specified on the attachment types form. The hanging part</p><p>of the chain is drawn as a line, of length equal to the hanging length and at the angle calculated using the above</p><p>theory. The supported part of the chain (if any is supported) is separately drawn as a blob at the seabed, directly</p><p>beneath the node. The drag chain drawing therefore directly reflects the way in which the chain is modelled.</p><p> Flex Joints are drawn as a circular blob using the colour and line style specified on the attachment types form.</p><p> Links and Winches are drawn as a straight line segments joining the connection points.</p><p>Lines, Links and Winches and Shapes are special slave objects that can be connected to other master objects – see</p><p>Connecting Objects. To allow these connections to be made, each slave object has a joint at each end that you can</p><p>connect to a master object or else leave Free. When the program is in Reset or Statics Complete state these joints are</p><p>drawn as follows:</p><p>The joint at End A of a line or end 1 of a Link or Winch is drawn as a small triangle. The other joints are drawn as</p><p>small squares. This distinguishes which end of a Line, Link or Winch is which.</p><p>If the joint is connected to a master object, then it is drawn in the colour of the master object to which it is</p><p>connected. If the joint is Free, then it is drawn in the colour of the Line, Link or Winch to which it belongs.</p><p>Shaded Drawing</p><p>For shaded views the various objects are drawn as follows:</p><p> View axes and global axes are drawn as small triplets of lines showing their origin and the orientation of their</p><p>axes. The wave, current and wind directions can be drawn as arrows in the top right hand corner of 3D views.</p><p>You can control both what is drawn (see 3D View Drawing Preferences) and the drawing data used.</p><p> The Sea Surface and Seabed are drawn as textured surfaces using their respective pen colours. Both surfaces</p><p>can be drawn with user-specified levels of translucency.</p><p> Shapes are drawn as solid objects and Planes allow for user-specified levels of translucency. Alternatively</p><p>Shapes can be represented by an imported 3D model.</p><p> Vessels are drawn as a solid, filled-in shape based on the wire frame data. Alternatively Vessels can be</p><p>represented by an imported 3D model.</p><p> 3D Buoys and Clumps are drawn as an ellipsoid with the specified volume and height.</p><p> Lumped 6D Buoys are drawn as a solid, filled-in shape based on the wire frame data. Spar Buoys and Towed</p><p>Fish are drawn as solid objects using the specified cylinder geometry. Alternatively 6D Buoys can be</p><p>represented by an imported 3D model.</p><p> Wings are drawn as plates using their specified span and chord. Alternatively they can be represented by an</p><p>imported 3D model.</p><p> Lines are drawn as a series of cylinders, one for each segment using the contact diameter as specified on the</p><p>Line Type form. There is also, on the Line Data form, a choice of which pen to use to draw the segments.</p><p> Drag Chains are drawn as a chain with bar diameter derived from the drag chain's effective diameter.</p><p>w User Interface, 3D Views</p><p>59</p><p> Flex Joints are drawn as cylinders with radius 2R and length 4R where R is the radius of the node to which the</p><p>flex joint is attached.</p><p> Links and Winches are drawn as a series of cylinders joining the connection points. The diameter of the</p><p>cylinders can be specified on the object's data form.</p><p>3.6.6 Selecting Objects</p><p>A single CLICK on or near an object in a 3D View selects it ready for further operations. The currently selected object</p><p>is indicated in the Status bar. All objects have a hot zone around them. If several objects have overlapping hot zones</p><p>at the mouse position, they will be selected in turn at subsequent CLICKS.</p><p>To deselect the object (without selecting another object) CLICK on the 3D view away from all objects. CLICK on an</p><p>object to open its data form.</p><p>3.6.7 Creating and Destroying Objects</p><p>When the model is in Reset or Statics Complete state then you can create and destroy objects using the mouse.</p><p>To create a new object, CLICK on the appropriate new object button on the tool bar or select the Model | New Object</p><p>menu item. The mouse cursor changes to show this. A new object of that type is created at the position of the next</p><p>CLICK on a 3D View.</p><p>You can also create a new object by copying an existing one. To do this select the object and press CTRL+C to take a</p><p>copy of it. You can now press CTRL+V (more than once if you want more than one copy) – again the mouse cursor</p><p>changes and the copy object is pasted at the position of the next mouse CLICK in a 3D view. This method of creating a</p><p>new object is particularly useful if you want an almost identical object – you can create a copy of it and then just</p><p>change the data that you want to differ.</p><p>To destroy an object, simply select it and then press the DELETE key. You will be asked to confirm the action.</p><p>3.6.8 Dragging Objects</p><p>An unlocked object may be dragged to relocate it by pressing the mouse button down and holding it down while</p><p>moving the mouse. When the mouse button is released, then the object will be positioned at the new location. The</p><p>current coordinates of the object are shown in the Status Bar during the drag operation.</p><p>Note: Objects must be dragged a certain minimum distance (as specified in the Preferences form) before</p><p>the drag operation is started. This prevents accidental movement of objects when DOUBLE CLICKING</p><p>etc.</p><p>Objects may be locked to prevent unintended drag operations moving them (see Locking an object). Their</p><p>coordinates may still be edited on their data form.</p><p>Note: Slave objects that are connected are moved relative to their master's local origin. Other objects are</p><p>moved in the global coordinate frame.</p><p>Dragging is only available in Reset or Statics Complete states, and when the object is not locked.</p><p>3.6.9 Connecting Objects</p><p>Unlocked slave objects (e.g. Lines, Links, etc.) can be connected to master objects using the mouse in a 3D View (see</p><p>Object Connections). First select the end of the slave that you want to connect by CLICKING on or near its end joint.</p><p>Then hold down the CTRL key while CLICKING on the master object – the two will then be connected together. This</p><p>operation is only permitted for master-slave object pairs, for example connecting a line to a vessel. The connection is</p><p>indicated in the Status Bar and the joint connected is drawn in the colour of the master object to show the</p><p>connection.</p><p>To Free a joint – i.e. to disconnect it – select it and then CTRL+CLICK on the sea surface.</p><p>To connect a joint to a Fixed Point, select it and then CTRL+CLICK on the global axes.</p><p>To connect an object to an Anchor (a fixed point with a</p><p>coordinate relative to the seabed), select it and then</p><p>CTRL+CLICK on the seabed grid. If the object is close to the seabed then the program snaps it onto the seabed. This</p><p>allows an object to be placed exactly on the seabed. If you require an anchor coordinate close to, but not on the</p><p>seabed, connect it to the seabed at a distance and then drag it nearer or edit the coordinate in the Data Form.</p><p>User Interface, Replays w</p><p>60</p><p>3.6.10 Printing, Copying and Exporting Views</p><p>3D Views may be printed, copied to the windows clipboard, or exported to a windows graphics metafile, so that the</p><p>pictures may be used in other applications such as word processors and graphics packages.</p><p>First select the view and adjust the viewpoint as desired. Then to copy to the clipboard press CTRL+C, or select Copy</p><p>from the pop-up menu. The pop-up menu also has commands to print or export the 3D view. If needed, you can first</p><p>adjust the printer setup using the Printer Setup command on the pop-up menu or on the File menu.</p><p>If you are printing the view on a black and white printer (or are transferring the view into a document which you</p><p>intend to print on a black and white printer) then it is often best to first set OrcaFlex to output in monochrome (use</p><p>the Tools|Preferences|Output menu item). This avoids light colours appearing as faint shades of grey.</p><p>After a 3D view has been transferred to another application you should be careful not to change its aspect ratio,</p><p>since this will produce unequal scaling in the vertical and horizontal directions and invalidate the scale bar. In Word</p><p>you can maintain aspect ratio by dragging the corners of the picture, whereas if you drag the centres of the sides</p><p>then the aspect ratio is changed.</p><p>3.7 REPLAYS</p><p>A Replay is a sequence of 3D views shown one after another to give an animation. A replay is therefore like a short</p><p>length of film, with each frame of the film being a snapshot of a model as it was at a given time.</p><p>There are various controls and parameters that allow you to control a replay.</p><p>There are two types of replay:</p><p> Active Simulation Replays show the model as it was at regularly spaced times during the currently active</p><p>simulation. This type of replay is therefore only available when a simulation is active and can only cover the</p><p>period that has already been simulated. If you have a time history graph window open when the replay is run,</p><p>then the replay time is indicated on the graph.</p><p> Custom Replays are replays where you have complete control over frames which make up the replay. This</p><p>means that, for example, you are not restricted to regularly spaced times; you can have frames from different</p><p>simulation files in the same replay; you can include frames showing the static configuration of a model; you are</p><p>able to vary the view size, view angles and view centre to achieve panning, rotating and zooming effects. Custom</p><p>replays were originally introduced to help visualise series of static snapshots, for example during a lowering</p><p>operation. However, the facility is very powerful and you are certainly not restricted to this application. See</p><p>Custom Replays for details.</p><p>Export Video</p><p>Replays can be exported as a video clip in AVI file format, using the Export Video button on the replay parameters</p><p>form. An AVI file is generated containing the replay using the most recently selected 3D view window and using the</p><p>same period, frame interval and speed as the replay.</p><p>When you export a video clip you will be asked to select a file name for the video using the standard Save File</p><p>window. At the bottom of this window is a checkbox titled Include frame details in video. If this is selected then</p><p>each frame in the video has details of that frame (e.g. simulation time) written in the top left hand corner of the</p><p>frame. There is also a button which provides a link to the Video preferences.</p><p>AVI is a standard video format, so the file can then be imported into other applications, for example to be shown in a</p><p>presentation. The compression method (the codec) used for the generating the video file can be set on the</p><p>Preferences form.</p><p>Note: AVI files can be very large if the window size is large or there are a lot of frames in the replay. Also,</p><p>resizing video clips (after pasting into your presentation) will introduce aliasing (digitisation</p><p>errors), so it is often best to set the 3D View window size to the required size before you export the</p><p>video.</p><p>3.7.1 Replay Parameters</p><p>The replay can be controlled by the following parameters that can be set in the Replay Parameters form,</p><p>accessed using the Replay Parameters button.</p><p>w User Interface, Replays</p><p>61</p><p>Replay Period</p><p>The part of the simulation that the replay covers. You can select to replay the whole simulation, just one simulation</p><p>stage (an asterisk * denotes an incomplete stage), the latest wave period or else a user specified period. If you select</p><p>User Specified then you can enter your own Start and End Times for the replay period. These can be set to '~'</p><p>which is interpreted as simulation start time and simulation finish time respectively.</p><p>Interval</p><p>The simulation time step size between frames of the replay. The value '~' is interpreted as the actual sample</p><p>interval, i.e. the smallest possible interval.</p><p>Using shorter intervals means that you see a smoother animation (though the extra drawing required may slow the</p><p>animation).</p><p>Example: For a simulation with stages of 8 seconds each, selecting stage 2 and a replay time step of 0.5 seconds</p><p>causes the replay to show 16 frames, corresponding to times 8.0, 8.5, 9.0, …, 15.5.</p><p>Target Speed</p><p>Determines how fast the replay is played. It is specified as a percentage of real time, so 100% means at real time,</p><p>200% means twice as fast etc.</p><p>Continuous</p><p>Continuous means replaying like an endless film loop, automatically cycling back to the first frame after the last</p><p>frame has been shown; this is suitable for replays of whole cycles of regular cyclic motion. Non-continuous means</p><p>that there will be a pause at the end of the replay, before it starts again at the beginning; this is more suitable for</p><p>non-cyclic motion.</p><p>All Views</p><p>If this is selected, then the replay is shown in all 3D Views simultaneously, allowing motion to be viewed from</p><p>several different viewpoints. Otherwise the replay is played in the currently selected view window only.</p><p>Show Trails</p><p>If this is selected, then when each frame of the replay is drawn the previous frame is first overdrawn in grey – this</p><p>results in grey 'trails' showing the path of each object.</p><p>3.7.2 Replay Control</p><p>The replay can be controlled from the Replay menu, by using toolbar buttons or with shortcut keys. In addition,</p><p>some replay settings can only be modified on the Replay Parameters form.</p><p>The toolbar has a section dedicated to replay control:</p><p>Figure: Replay toolbar controls</p><p>The replay control buttons, menu items are listed in the table below:</p><p>Button Menu Item Shortcut Action</p><p>Replay | Start Replay CTRL+R Start replay</p><p>Replay | Stop Replay CTRL+R Stop replay</p><p>Replay | Step Replay Forwards CTRL+A Step to next frame and pause</p><p>+ SHIFT</p><p>Replay | Step Replay Backwards CTRL+B Step to previous frame and pause</p><p>Replay | Replay Faster CTRL+F Speed up replay</p><p>Replay | Replay Slower SHIFT+CTRL+F Slow down replay</p><p>Replay | Replay Parameters CTRL+D Edit replay parameters</p><p>User Interface, Replays w</p><p>62</p><p>Replay Slider Control</p><p>The final part of the replay toolbar is the replay slider. This allows direct control of the replay</p><p>time. Drag the slider to the left to move to an earlier part of the replay and to the right to move to a later part. For</p><p>fine grained adjustment of replay time you can use the Replay | Step Replay Forwards and Replay | Step Replay</p><p>Backwards actions or alternatively their shortcuts, CTRL+A and CTRL+B. The replay time is displayed on and can be</p><p>controlled from Time History graphs.</p><p>3.7.3 Custom Replays</p><p>Custom replays allow you to piece</p><p>Buoys 389</p><p>6.9.1 Wings 390</p><p>6.9.2 Common Data 391</p><p>6.9.3 Applied Loads 393</p><p>6.9.4 Wing Data 393</p><p>6.9.5 Wing Type Data 394</p><p>6.9.6 Lumped Buoy Properties 396</p><p>6.9.7 Lumped Buoy Drawing Data 397</p><p>6.9.8 Spar Buoy and Towed Fish Properties 398</p><p>6.9.9 Spar Buoy and Towed Fish Drag & Slam 400</p><p>6.9.10 Spar Buoy and Towed Fish Added Mass and Damping 401</p><p>6.9.11 Spar Buoy and Towed Fish Drawing 402</p><p>6.9.12 Shaded Drawing 403</p><p>6.9.13 Other uses 405</p><p>6.9.14 External Functions 405</p><p>6.9.15 Properties Report 405</p><p>6.9.16 Results 406</p><p>6.9.17 Buoy Hydrodynamics 409</p><p>w Contents</p><p>9</p><p>6.9.18 Hydrodynamic Properties of a Rectangular Box 409</p><p>6.9.19 Modelling a Surface-Piercing Buoy 412</p><p>6.10 3D Buoys 414</p><p>6.10.1 Data 415</p><p>6.10.2 Properties Report 416</p><p>6.10.3 Results 416</p><p>6.11 Winches 417</p><p>6.11.1 Data 418</p><p>6.11.2 Wire Properties 418</p><p>6.11.3 Control 419</p><p>6.11.4 Control by Stage 419</p><p>6.11.5 Control by Whole Simulation 421</p><p>6.11.6 Drive Unit 421</p><p>6.11.7 External Functions 421</p><p>6.11.8 Results 421</p><p>6.12 Links 422</p><p>6.12.1 Data 423</p><p>6.12.2 Results 424</p><p>6.13 Shapes 425</p><p>6.13.1 Data 426</p><p>6.13.2 Blocks 427</p><p>6.13.3 Cylinders 428</p><p>6.13.4 Curved Plates 428</p><p>6.13.5 Planes 429</p><p>6.13.6 Drawing 430</p><p>6.13.7 Results 431</p><p>6.14 All Objects Data Form 431</p><p>7 MODAL ANALYSIS 433</p><p>7.1 Data and Results 433</p><p>7.2 Theory 434</p><p>8 FATIGUE ANALYSIS 437</p><p>8.1 Introduction 437</p><p>8.2 Commands 438</p><p>8.3 Data 439</p><p>8.4 Load Cases Data for Regular Analysis 440</p><p>8.5 Load Cases Data for Rainflow Analysis 441</p><p>8.6 Load Cases Data for Spectral Analysis 441</p><p>8.7 Load Cases Data for SHEAR7 443</p><p>8.8 Components Data 443</p><p>8.9 Analysis Data 444</p><p>8.10 S-N and T-N Curves 445</p><p>8.11 Integration Parameters 446</p><p>Contents w</p><p>10</p><p>8.12 Results 446</p><p>8.13 Automation 447</p><p>8.14 Fatigue Points 448</p><p>8.15 How Damage is Calculated 448</p><p>9 VIV TOOLBOX 451</p><p>9.1 Frequency Domain Models 451</p><p>9.1.1 VIVA 451</p><p>9.1.2 SHEAR7 455</p><p>9.2 Time Domain Models 462</p><p>9.2.1 Wake Oscillator Models 465</p><p>9.2.2 Vortex Tracking Models 468</p><p>9.2.3 VIV Drawing 474</p><p>w Introduction, Installing OrcaFlex</p><p>11</p><p>1 INTRODUCTION</p><p>Welcome to OrcaFlex (version 9.6a), a marine dynamics program developed by Orcina for static and dynamic</p><p>analysis of a wide range of offshore systems, including all types of marine risers (rigid and flexible), global analysis,</p><p>moorings, installation and towed systems.</p><p>OrcaFlex provides fast and accurate analysis of catenary systems such as flexible risers and umbilical cables under</p><p>wave and current loads and externally imposed motions. OrcaFlex makes extensive use of graphics to assist</p><p>understanding. The program can be operated in batch mode for routine analysis work and there are also special</p><p>facilities for post-processing your results including fully integrated fatigue analysis capabilities.</p><p>OrcaFlex is a fully 3D non-linear time domain finite element program capable of dealing with arbitrarily large</p><p>deflections of the flexible from the initial configuration. A lumped mass element is used which greatly simplifies the</p><p>mathematical formulation and allows quick and efficient development of the program to include additional force</p><p>terms and constraints on the system in response to new engineering requirements.</p><p>In addition to the time domain features, modal analysis can be performed for either the whole system or for</p><p>individual lines. RAOs can be calculated for any results variable using the Spectral Response Analysis feature.</p><p>OrcaFlex is also used for applications in the Defence, Oceanography and Renewable energy sectors. OrcaFlex is fully</p><p>3D and can handle multi-line systems, floating lines, line dynamics after release, etc. Inputs include ship motions,</p><p>regular and random waves. Results output includes animated replay plus full graphical and numerical presentation.</p><p>If you are new to OrcaFlex then please see the tutorial and examples.</p><p>For further details of OrcaFlex and our other software, please contact Orcina or your Orcina agent.</p><p>Copyright notice</p><p>Copyright Orcina Ltd. 1987-2012. All rights reserved.</p><p>1.1 INSTALLING ORCAFLEX</p><p>Hardware Requirements</p><p>OrcaFlex can be installed and run on any computer that has:</p><p> Windows XP, Windows Vista, Windows 7 or Windows 8. Both 32 bit and 64 bit versions of Windows are</p><p>supported.</p><p> If you are using small fonts (96dpi) the screen resolution must be at least 1024×768. If you are using large fonts</p><p>(120dpi) the screen resolution must be at least 1280×1024.</p><p>However, OrcaFlex is a powerful package and to get the best results we would recommend:</p><p> A 64 bit edition of Windows 7 or later.</p><p> A powerful processor with fast floating point and memory performance. This is the most important factor since</p><p>OrcaFlex is a computation-intensive program and simulation run times can be long for complex models.</p><p> At least 4GB of memory. This is less important than processor performance but some aspects of OrcaFlex do</p><p>perform better when more memory is available, especially on multi-core systems. If you have a multi-core</p><p>system with a 64 bit version of Windows then you may benefit from fitting even more memory.</p><p> A multi-core system to take advantage of OrcaFlex's multi-threading capabilities.</p><p> As much disk space as you require to store simulation files. Simulation files vary in size, but can be hundreds of</p><p>megabytes each for complex models.</p><p> A screen resolution of 1280×1024 or greater with 32 bit colour.</p><p> A DirectX 9 compatible graphics card with at least 256MB memory for the most effective use of the shaded</p><p>graphics facility.</p><p> Microsoft Excel (Excel 2000, or later) in order to use the OrcaFlex automation facilities. Both 32 bit and 64 bit</p><p>versions of Excel are supported.</p><p>Installation</p><p>To install OrcaFlex:</p><p>Content/html/What_s_New_in_this_Version.htm</p><p>Introduction, Installing OrcaFlex w</p><p>12</p><p> You will need to install from an account with administrator privileges.</p><p> If installing from disc, insert the OrcaFlex installation disc and run the Autorun.exe program on the disc (on</p><p>many machines this program will run automatically when you insert the disc). Then click on 'Install OrcaFlex'.</p><p> If you have received OrcaFlex by e-mail or from the web you will have a zip file, and possibly a number of</p><p>licence files (.lic). Extract the files from the zip file to some temporary location, and save the licence files to the</p><p>same folder. Then run the extracted file Setup.exe.</p><p> You will also need to install the OrcaFlex dongle supplied by Orcina. See below for details.</p><p>For further details, including information on network and silent installation, click on Read Me on the Autorun menu</p><p>or open the file Installation Guide.pdf on the disc. If you have any difficulty installing OrcaFlex please contact Orcina</p><p>or your Orcina agent.</p><p>Orcina Shell Extension</p><p>When you install OrcaFlex the Orcina Shell Extension is also installed. This integrates with Windows Explorer, and</p><p>associates the data and simulation file types (.dat and .sim) with OrcaFlex. You can then open an OrcaFlex file by</p><p>simply double-clicking the filename in Explorer. The shell extension also provides file properties information, such</p><p>as which version of OrcaFlex wrote the file and the Comments text for the model in the file. For details see the file</p><p>OrcShlEx\ReadMe.htm on the OrcaFlex installation disc.</p><p>Installing the Dongle</p><p>OrcaFlex is supplied with a dongle, a small hardware device that must be attached to the machine or to the network</p><p>to which the machine is attached.</p><p>Note: The dongle is effectively your licence to run one copy (or more, if the dongle is enabled for more</p><p>copies) of OrcaFlex. It is, in essence, what you have purchased or leased, and it should be treated</p><p>with appropriate care and security. If you lose your dongle you cannot run OrcaFlex.</p><p>Warning: Orcina can normally resupply disks or manuals (a charge being made to cover costs) if they are lost</p><p>or damaged. But we can only supply a new dongle in the case where the old dongle is returned to</p><p>us.</p><p>together arbitrary frames from one or more OrcaFlex files. Each frame of the</p><p>replay can be either the static configuration, or a snapshot of a specified time in a dynamic simulation file.</p><p>Using frames of static configurations you can string together a series of static snapshots giving, for example, an</p><p>animation of an installation procedure. Using frames from dynamic simulation files allows you to create replays</p><p>where the frames are from one or more simulations, and, if you wish, vary the time intervals between frames.</p><p>Frames of both static and dynamic configurations can be included in the same custom replay. In addition you are</p><p>able to vary the view size, view angles and view centre to achieve panning, rotating and zooming effects.</p><p>To use the custom replay feature you must first set the Replay Type data item on the Replay Parameters form to</p><p>Custom Replay. Next you must build the custom replay which is most easily done using the Custom Replay Wizard,</p><p>which can be opened by clicking the Custom Replay Wizard button.</p><p>Replay Specification</p><p>This is the file containing the custom replay specification – that is the file that is saved by the Custom Replay Wizard.</p><p>Custom Replay Parameters</p><p>Custom replays also make use of some of the parameters needed for standard simulation replays. These parameters</p><p>are Target Speed, Continuous, All Views and Show Trails.</p><p>3.7.4 Custom Replay Wizard</p><p>The Custom Replay Wizard allows you to define a series of replay sections. Each replay section can show either:</p><p>1. A series of regularly spaced snapshots from a simulation file.</p><p>2. The static configuration of a model specified by either a data file or a simulation file.</p><p>Different files can be used for different replay sections.</p><p>Custom Replay Files</p><p>When you have built your custom replay you must save it using the File menu or save button on the toolbar. Custom</p><p>replay files can be opened in a similar way.</p><p>We recommend that you save your custom replay file before you start setting up the replay sections. This is because</p><p>once you have saved the custom replay file you will be able to use relative paths for the OrcaFlex file names.</p><p>Custom Replay Data</p><p>Custom replay specifies view parameters (size, position, angles and graphics mode)</p><p>If this data item is not checked then the replay will use the view parameters of whichever 3D View window it</p><p>appears in. In this mode of operation you will be able manually to pan, rotate and zoom the 3D View using the</p><p>normal buttons and shortcuts.</p><p>If this data item is checked then you will be required to specify the view parameters (view size, view centre, view</p><p>azimuth, view elevation and graphics mode) for each replay section. This allows you to include panning, rotating</p><p>and zooming effects in your replay.</p><p>While learning how custom replays work we recommend that you do not check this data item.</p><p>Use smoothed panning, rotating and zooming effects</p><p>This item is only available if the "Custom replay specifies view parameters" option is enabled. If you are panning,</p><p>rotating and zooming during replay sections then the transition from one section to another sometimes appears to</p><p>be disjointed. If this option is checked then the transition between sections is smoothed.</p><p>w User Interface, Data Forms</p><p>63</p><p>Frame interval in real time</p><p>OrcaFlex needs to know how fast to play the replay. This data item specifies the interval, in real time, between each</p><p>replay frame, assuming a target replay speed of 100%. If the target replay speed is, say 200%, then the interval</p><p>between frames will be half this value, and so on.</p><p>Replay Sections</p><p>You can specify any number of replay sections. For each replay section you must also specify the following:</p><p>Replay Section Name</p><p>This is a descriptive name for the replay section. When the replay is running OrcaFlex displays a description of the</p><p>current frame in the message box on the status bar – this includes the replay section name. This description can also</p><p>be included in exported videos.</p><p>OrcaFlex File Name</p><p>The model to be used for this section – either a data file (.dat or .yml) or a simulation file (.sim).</p><p>Dynamics</p><p>This setting determines whether the replay section defines snapshots from a dynamic simulation or a static</p><p>configuration. If the file is a data file then the replay section will show the static configuration and so this data item</p><p>cannot be edited.</p><p>The custom replay displays static configurations for a data file by loading the file and then performing the static</p><p>calculation. This can be time consuming – static state simulation files can be used instead to avoid the overhead of</p><p>performing statics each time the replay is shown.</p><p>Simulation Time From, Simulation Time To</p><p>This specifies the period of the dynamic simulation covered by the replay section. These are OrcaFlex simulation</p><p>times for the specified simulation file of this replay section.</p><p>If the replay section is a static snapshot then these data items are not editable.</p><p>Number of Frames</p><p>This is the total number of frames in the replay section. If your custom replay is a series of static snapshots then you</p><p>would usually set this value to 1.</p><p>Included in Replay</p><p>This allows you to exclude certain sections from the replay. This may be useful while developing the custom replay</p><p>because it allows you to concentrate on particular replay sections.</p><p>View Parameter data</p><p>The following data items are only available when the specifies view parameters option is checked.</p><p>From View Parameters, To View Parameters</p><p>The view size, view centre, view azimuth and view elevation for the first and last frames of the replay section. These</p><p>view parameters are varied between these values for the other frames in the replay section.</p><p>Hint: These values can be copied from OrcaFlex's View Parameters form using the clipboard.</p><p>Graphics Mode</p><p>Specifies either the Wire frame or Shaded graphics mode for the replay section.</p><p>3.8 DATA FORMS</p><p>Each object in the model has data items that define its properties. The data are examined and edited in the object's</p><p>Data Form, which can be accessed by various methods:</p><p> use the Model Browser</p><p> DOUBLE CLICK the object in a 3D view</p><p> RIGHT CLICK the object in a 3D view and use the pop-up menu.</p><p>User Interface, Data Forms w</p><p>64</p><p>If a simulation is active then most data items cannot be changed since they affect the calculation, but you can change</p><p>things like the object's colour.</p><p>Control Buttons</p><p>Ok</p><p>Accepts the data changes made and then closes the form.</p><p>Cancel</p><p>Cancels the data changes made and then closes the form.</p><p>Next</p><p>Accepts the data changes made and then displays the next form in sequence. Holding the SHIFT key down while</p><p>CLICKING the Next button accepts the changes and then displays the previous data form in sequence. You can also</p><p>use the keyboard shortcuts F6 for next and SHIFT+F6 for previous.</p><p>Pop-up Menu</p><p>The pop-up menu on a data form provides various facilities, including:</p><p> The data form can be printed, copied to the clipboard or exported to a file. The data for the whole model may be</p><p>printed using the File | Print menu item.</p><p> Access to the next and previous data form and to the Variable Data form.</p><p> The batch script names for the currently-selected block of data items.</p><p> Data forms for 3D Buoys, 6D Buoys, Vessels and Lines provide a Connections Report. This is a spreadsheet</p><p>listing information about other objects connected to it. Note that the same information, but for all objects in the</p><p>model, can be displayed using the Model | Show Connections Report menu item.</p><p>Object properties reports</p><p>On data forms of some model objects, a report of the properties of that object. It can be opened from the popup</p><p>menu or alternatively by pressing Alt+Enter. The report displays properties like weight in air, displacement, weight</p><p>in water etc.</p><p>These reports are currently available for General Data, 3D Buoys, 6D Buoys, Vessels, Lines, Line Types, Clump Types</p><p>and Drag</p><p>Chain Types.</p><p>Calculator</p><p>A simple calculator is available from any OrcaFlex data form. It can be opened from the popup menu or alternatively</p><p>by pressing F12. Numbers can be transferred to and from it with standard Windows copy (CTRL+C) and paste</p><p>(CTRL+V). The calculator can also be closed by pressing F12 – if you do this then the value in the calculator is</p><p>transferred to the active edit cell.</p><p>3.8.1 Data Fields</p><p>Data items on each Data Form are displayed in Fields, generally with related fields organised into Groups or Tables.</p><p>You can select a field with the mouse, or use the keyboard to navigate around the form. TAB moves from group to</p><p>group, and the arrow keys move across the fields in a group.</p><p>The following types of fields are used:</p><p>Text</p><p>A general string of text, used for example for titles and comments.</p><p>Name</p><p>Each object is given a name, which you can edit. Object names must be unique – you cannot have two objects with</p><p>the same name. Certain names are reserved for special purposes: Fixed, Anchored and Free (see Connecting</p><p>Objects).</p><p>w User Interface, Data Forms</p><p>65</p><p>Numeric</p><p>Numbers can be entered in a number of formats such as 3, 3.0, 0.3, .3 or 3.0e6 or 3.0E6. It is possible to enter more</p><p>digits than those shown in the field, but beware that it will not be possible to see them again without editing again</p><p>and using the arrow keys to examine the rest of field.</p><p>For some numeric data items the value '~' is permitted. For example this is sometimes used to mean 'default value'.</p><p>Details are given in the descriptions of the relevant data items.</p><p>Spin Buttons</p><p>These are small buttons with up and down arrows, used for incrementing and decrementing the associated field</p><p>(such as the number of entries in a table). Using the mouse, CLICK on the upper or lower parts of the button to</p><p>increment or decrement the associated counter.</p><p>Multi-choice Buttons</p><p>These are used when a number of options are available. Activate the button to step on to the next available option.</p><p>Check Boxes</p><p>These show a tick, meaning selected, or are blank, meaning not selected. CLICK or press ENTER to change.</p><p>Colour Selection</p><p>These show as a block of colour. DOUBLE CLICK or press ENTER to open the Colour Selection dialogue window. The</p><p>desired colour may now be selected.</p><p>List Boxes</p><p>These show the current selection, such as the name of another object that this object is connected to. DOUBLE CLICK</p><p>or press ENTER to show a List Box, and then select another item and ENTER to accept the new choice.</p><p>3.8.2 Data Form Editing</p><p>The TAB, SHIFT+TAB, HOME, END and ARROW keys and the mouse can be used to navigate around the Edit Form.</p><p>Editing mode is entered by DOUBLE CLICKING a cell with the mouse, or by starting to type alphanumeric characters,</p><p>which are entered into the field as they are typed. The characters that have been typed can be edited by using the</p><p>arrow keys to move around (now within the field) and the BACKSPACE and DELETE keys.</p><p>Editing mode is ended, and the new value takes effect, when you press ENTER or select another field or button on the</p><p>form. To end editing mode but reject the edit (and so keep the old value) press ESC.</p><p>Many numeric fields have limits on the range of values that can be entered, for example an object's mass must</p><p>always be greater than zero. Warnings are given if invalid values are typed.</p><p>Input can also be from the Windows clipboard. CTRL+C copies the selected field or block of fields to the clipboard</p><p>whilst CTRL+V pastes from the clipboard into the selected field. In this way data can be easily transferred to and</p><p>from Spreadsheets, Word Processors, etc.</p><p>Mouse Actions</p><p>CLICK Select Field</p><p>CLICK+DRAG,</p><p>SHIFT+CLICK</p><p>Select a block of fields</p><p>DOUBLE CLICK Start Edit Mode in this field (please also see Data Fields)</p><p>SECONDARY</p><p>BUTTON CLICK</p><p>Context sensitive pop-up menu for copying, exporting and printing the form and, for some</p><p>model objects, viewing additional properties</p><p>Group Movement</p><p>TAB Next Group</p><p>SHIFT+TAB Previous Group</p><p>ALT+… Move to the group with this letter underlined in its heading</p><p>Field Movement</p><p>← ↑ ↓ → Go to adjacent row or column</p><p>HOME Go to leftmost column</p><p>User Interface, Results w</p><p>66</p><p>Mouse Actions</p><p>END Go to rightmost column</p><p>PAGE UP Go to top row</p><p>PAGE DOWN Go to bottom row</p><p>Table Editing</p><p>INSERT, DELETE Insert or delete rows</p><p>Start Editing</p><p>0…9, A…Z Edit (replace)</p><p>During Editing</p><p>← →, HOME, END Move within field</p><p>End Editing</p><p>ESC Cancel edit</p><p>↑ ↓ Accept edit and move to previous/next row</p><p>ENTER Accept edit</p><p>Copy / Paste</p><p>CTRL+C Copy selected field/block to clipboard</p><p>CTRL+V Paste from clipboard into selected field</p><p>CTRL+D Fill selection from top (copy top cell down)</p><p>CTRL+R Fill selection from left (copy leftmost cell to right)</p><p>CTRL+U</p><p>SHIFT+CTRL+D</p><p>Fill selection from bottom (copy bottom cell up)</p><p>CTRL+L</p><p>SHIFT+CTRL+R</p><p>Fill selection from right (copy rightmost cell to left)</p><p>3.9 RESULTS</p><p>3.9.1 Producing Results</p><p>You can access results by either CLICKING on the Results button on the toolbar or by using the Select Results</p><p>menu item; the Select Results form then appears.</p><p>There is a Keep Open switch on the form's context menu, which allows you to choose whether the form</p><p>automatically closes when you select a result, or alternatively stays open (and on top) until you explicitly close it.</p><p>Graphs and Tables can be sent straight to the printer by CLICKING the Print button. If the values of a graph are</p><p>required in text form then CLICK the Values button – this give the values in a Spreadsheet window, which can handle</p><p>multiple variables if desired.</p><p>The Select Results form allows you to select the results you want by specifying:</p><p>Result Type</p><p>This option allows you to select which of the various types of results output you require. Results are available as text</p><p>tables (summary results, full results, offset tables, statistics, linked statistics, extreme value statistics or line clashing</p><p>reports) or as graphs (time histories, range graphs, XY graphs, offset graphs or spectral response graphs). The types</p><p>of results available depend on the current model state.</p><p>Object</p><p>The object for which you want results (selected in the same way as in the Model Browser) and for some objects</p><p>which point in the object.</p><p> For the Environment you must specify the global X,Y,Z coordinates of the Position for which you want results.</p><p> For 6D Buoys that have wings attached, results for the buoy and for each wing are available separately.</p><p> For 6D Buoys and Vessels the translational position, velocity and acceleration results are reported at a user</p><p>specified Position on the object. The coordinates of this Position are specified in object local coordinates.</p><p>w User Interface, Results</p><p>67</p><p> For lines you must specify the arc length along the line – see Line Results.</p><p>Period</p><p>For time histories, XY graphs and range graphs you must specify the period of the simulation to be included. This</p><p>can be:</p><p> One of the numbered stages of the simulation.</p><p> The Whole Simulation.</p><p> A Specified Period, defined by a start and end time. These time values can be set to '~' which is interpreted as</p><p>simulation start time and simulation finish time respectively.</p><p> The Latest Wave (only available for regular wave simulations) which is defined to be the wave period</p><p>immediately preceding the latest simulation time.</p><p>For Range Graphs the period can also be Static State or Instantaneous Value:</p><p> The Static State period is only available after a statics calculation and the graph shows a curve of the values in</p><p>the static configuration.</p><p> The Instantaneous Value period is available when a simulation has been run. It shows a curve of the values at</p><p>the instantaneous simulation time. This is normally the latest simulated time. However, if a replay is active then</p><p>the graph shows a curve of values at the active replay time. This allows you to see, for an entire line, how a</p><p>results variable</p><p>evolves over a simulation.</p><p>Variable</p><p>The desired variable(s).</p><p>Definitions of the results variables can be obtained by selecting them in the Variable list box and then pressing F1.</p><p>Logging for results</p><p>The summary and full results are taken directly from the current state of the model. All the other results are derived</p><p>from the simulation log file which OrcaFlex creates automatically when a simulation is run. As the simulation</p><p>progresses, OrcaFlex samples the variables for each object at regular intervals and stores the sampled values in the</p><p>log file. All time histories, statistics and range graphs are derived from the simulation log file.</p><p>You can control the time resolution of the results by setting the Target Sample Interval data item on the general data</p><p>form. This must be done before the simulation is started. Decreasing the sample interval will improve the time</p><p>resolution of the results (and increase the number of samples taken). However, because more samples are taken this</p><p>will also increase the size of the simulation file that is created.</p><p>Spike Logging</p><p>A special algorithm is used for logging results that tend to vary rapidly to ensure that any spikes that may occur</p><p>between samples are recorded. We refer to this algorithm as spike logging.</p><p>Line Results</p><p>OrcaFlex spike logs Effective Tension, Torque, Clash Force, Clash Energy, Solid Contact Force, End Force results and</p><p>Vortex Force results. In addition other results which are derived from these quantities are effectively spike logged</p><p>by association. Such variables include Wall Tension, Normalised Tension, Direct Tensile Strain, ZZ Strain, Worst ZZ</p><p>Strain, Direct Tensile Stress, von Mises Stress, Max von Mises Stress and ZZ Stress.</p><p>Link and Winch Results</p><p>OrcaFlex spike logs Tension and Velocity.</p><p>Solid Results</p><p>OrcaFlex spike logs contact force magnitude.</p><p>General Results</p><p>OrcaFlex spike logs Implicit solver iteration count and Implicit solver time step.</p><p>User Interface, Results w</p><p>68</p><p>Inadequate segmentation warning</p><p>If any lines have, during the simulation, gone into greater compression than their segment Euler load then a warning</p><p>note is added to the Results form. Such lines are marked with the symbol § in the Model Browser. Usually this</p><p>means that finer segmentation is needed in some sections of these lines in order to model compression adequately.</p><p>Offset warning</p><p>If any of the multiple statics calculations have failed then a warning note is added to the Results form.</p><p>3.9.2 Selecting Variables</p><p>Each object has associated with it:</p><p> A currently selected variable that will be used for graphs.</p><p> A set of statistics variables that will be included in statistics reports.</p><p>For the currently selected object, the currently selected variables are shown in a list on the results selection form.</p><p>If Statistics results are selected, then the list shows the set of variables that will be included in the statistics report</p><p>and you can add or remove variables by CLICKING on them in the list.</p><p>If a Time History is selected, the list shows the (single) currently selected variable and you can select a different</p><p>variable by CLICKING on it in the list.</p><p>You can also multi-select variables, using:</p><p>CLICK select one variable</p><p>DRAG select a range of variables</p><p>SHIFT+CLICK select a range of variables</p><p>CTRL+CLICK add / remove one variable</p><p>CTRL+DRAG add / remove range of variables</p><p>If more than one variable is selected, then the Values button will give a single Spreadsheet Window with a time</p><p>history column for each selected variable, and the Graph button will give a separate Graph Window for each</p><p>variable.</p><p>New columns can be appended to existing time history spreadsheet windows, as follows:</p><p> Select the spreadsheet window to which you want to append, by clicking on it.</p><p> Then open the Select Results form and select the variables that you want to append.</p><p> Then hold the CTRL button down and click the Values button.</p><p> Provided that the selected spreadsheet window is a time history values table and that the time periods for both</p><p>sets of histories match, then the new time histories will be appended to the active window. This allows you to</p><p>have a single window containing results from different objects.</p><p>3.9.3 Summary and Full Results</p><p>These spreadsheet windows give the current state of an object or of the whole model. For example, in</p><p>Statics Complete state the full results tables show the positions of objects in their static position. If a simulation is</p><p>active, then they show the positions of objects at the latest time calculated.</p><p>To obtain one of these results tables:</p><p> Select Summary Results or Full Results on the Results form.</p><p> Select the object required.</p><p> Click the Table button.</p><p>The summary results are simply an abbreviated form of the full results, in which the results for lines only include</p><p>the end nodes, not all of the intermediate nodes.</p><p>When the model is in Statics Complete state the summary and full results include estimates of the shortest natural</p><p>periods of objects or of the whole model. These can be used to determine suitable simulation time steps. The</p><p>simulation inner time step should normally be no more than 1/10th of the shortest natural period of the model –</p><p>w User Interface, Results</p><p>69</p><p>this is given at the top of the summary results or full results report for All Objects. In addition the full results table</p><p>for a line contains detailed reports of the shortest natural periods.</p><p>3.9.4 Statistics</p><p>The Statistics report provides, for each statistics variable:</p><p> The minimum and maximum values and the simulation times when they occurred.</p><p> The mean and standard deviation (i.e. the root mean square about the mean).</p><p>These statistics are reported for each of a number of periods of the simulation. If Statistics by Wave Period is</p><p>selected then these periods are successive wave periods; otherwise they are the stages of the simulation.</p><p>To obtain a Statistics report:</p><p> Select Statistics.</p><p> Select the object and the variables of interest (see Selecting Variables).</p><p> CLICK the Table button.</p><p>The report is presented in a spreadsheet.</p><p>Note: Be careful when interpreting statistics of Line Clearance and Seabed Clearance, since these results</p><p>are already minima – the shortest distance to any other line and to any point on the seabed. For</p><p>example, the maximum of Line Contact Clearance will be the maximum value that the smallest</p><p>clearance took during the period.</p><p>3.9.5 Linked Statistics</p><p>The Linked Statistics table relates a group of variables for a given object. For a specified group of variables and a</p><p>specified period of simulation, OrcaFlex finds the minimum and maximum of each variable and reports these</p><p>extreme values, the times they occurred and the values that all the other variables took at those times.</p><p>The report also includes:</p><p>μ mean,</p><p>σ standard deviation,</p><p>Tz mean up-crossing period, estimated as the average time between successive up-crossings of the mean value μ,</p><p>Tc mean crest period, estimated as the average time between successive local maxima,</p><p>m0 zeroth spectral moment, estimated as σ2,</p><p>m2 second spectral moment, estimated as m0/Tz</p><p>2,</p><p>m4 fourth spectral moment estimated as m2/Tc</p><p>2,</p><p>ε spectral bandwidth parameter, estimated as (1-Tc</p><p>2/Tz</p><p>2)½,</p><p>To obtain a Linked Statistics report:</p><p> Select Linked Statistics.</p><p> Select the required object and period.</p><p> Select the variables of interest (see Selecting Variables).</p><p> CLICK the OK button.</p><p>The report is presented in a spreadsheet.</p><p>Note: Be careful when interpreting statistics of Line Clearance and Seabed Clearance, since these results</p><p>are already minima – the shortest distance to any other line and to any point on the seabed. For</p><p>example, the maximum of Line Contact Clearance will be the maximum value that the smallest</p><p>clearance took during the period.</p><p>3.9.6 Offset Tables</p><p>These Text Windows are available only after multiple statics calculations and</p><p>only for vessels. For a given offset</p><p>direction they report the total load on the vessel and show how it varies with offset distance. The worst tension in</p><p>any segment of any line connected to the vessel is also reported for each offset.</p><p>User Interface, Results w</p><p>70</p><p>To obtain an Offset Table:</p><p> Select Offset Table on the Results form.</p><p> Select the offset vessel.</p><p> Select the offset direction required.</p><p> CLICK the Table button.</p><p>The report is presented in a spreadsheet.</p><p>3.9.7 Line Clashing Report</p><p>The Line Clashing Report produces a detailed tabular report about the line clashing events during a simulation.</p><p>To obtain a Line Clashing Report:</p><p> Select Line Clashing Report on the Results form.</p><p> Select a line.</p><p> Select the period required.</p><p> CLICK the Table button.</p><p>The report is presented in a spreadsheet.</p><p>Contents of the Line Clashing Report</p><p>The report lists a summary table followed by a detailed table as described below.</p><p>Summary table</p><p>The summary table lists all clash events for segments on the selected line. A clash event is deemed to start when a</p><p>segment from the selected line first comes into contact with another line segment. We shall refer to the selected line</p><p>as L1 and to the particular segment on this line as S1. The clash event ends when S1 is no longer in contact with any</p><p>other line segments.</p><p>Note: During the course of a clash event the segment S1 may be in contact with a number of different line</p><p>segments from other lines, e.g. if the clash is a sliding contact. This is counted as a single clash</p><p>event from the perspective of S1.</p><p>For each clash event the following results are reported:</p><p>Event number</p><p>A number of clash events may occur during the simulation. Each event is given a number to identify it. This is useful</p><p>when relating the summary results of a clash event to the detailed results.</p><p>Segment number and segment arc length</p><p>This identifies the segment S1 on the selected line.</p><p>Start Time, End Time and Duration</p><p>The simulation time of the start and end of the clash event together with its duration.</p><p>Total Impulse</p><p>The total impulse of the clash event.</p><p>Peak Clash Force</p><p>A scalar value reporting the greatest value of clash force achieved during the clash event. The clash force vector is</p><p>monitored during each clash event and the greatest magnitude of this vector is reported.</p><p>Peak Clash Energy</p><p>A scalar value reporting the greatest value of clash energy achieved during the clash event.</p><p>Max Penetration</p><p>At each time step we calculate the depth of penetration between the outer surfaces of segment S1 and all other</p><p>segments. Let S2 be a segment on another line.</p><p>w User Interface, Results</p><p>71</p><p>Let the radii of the two segments be r1 and r2 (as defined by the line type contact diameter). OrcaFlex calculates the</p><p>shortest separation distance, d, between the centrelines of the two segments. The penetration of these two segments</p><p>is defined to be (r1 + r2) – d. The value reported as Max Penetration is the maximum value of penetration between</p><p>segment S1 and any other segment over the duration of the clash event.</p><p>Detailed table</p><p>The detailed table reports information about each individual contact between segment S1 and another segment. If</p><p>during the course of a clash event segment S1 is in contact with a number of segments on other lines then the start</p><p>time, end time and duration of each of those individual contacts is reported.</p><p>Contact velocity</p><p>The detailed table also includes the contact velocity for each individual contact. This is the normal component of</p><p>relative velocity of the two contact points at the start of the time step during which the clash event started.</p><p>3.9.8 Time History and XY Graphs</p><p>Time History graphs are of a single variable against time. XY graphs are of one time dependent variable against</p><p>another.</p><p>The period of simulation covered by the graph is chosen from a list.</p><p>To obtain a Time History or XY Graph:</p><p>1. Select Time History or XY Graph on the Results form.</p><p>2. Select the object required.</p><p>3. Select the variable required (see Selecting Variables). More than one variable can be selected for time histories.</p><p>For XY graphs the steps 2 and 3 need to be done for both axes. Do this by CLICKING on one of the options labelled X-</p><p>axis or Y-axis, which are located at the bottom of the results form, and then repeating steps 2 and 3.</p><p> Select the period required.</p><p> CLICK the Graph button.</p><p>Time history and XY graphs are displayed in Graph Windows and they are "live" – i.e. they are regularly updated</p><p>during the simulation. You can therefore set up one or more graph windows at the start of a simulation and watch</p><p>the graphs develop as the simulation progresses. If you reset the simulation then the curves will be removed but the</p><p>graphs will remain, so you can adjust the model and re-run the simulation and the graphs will then be redrawn.</p><p>Graphs are automatically deleted if the object that they refer to is removed, for example by loading a new model.</p><p>Range Jump Suppression</p><p>For time histories of angles OrcaFlex chooses the angle's range so that the time history is continuous.</p><p>For example consider vessel heading, which is normally reported in the range -180° to +180°. If the vessel's heading</p><p>passes through 180° then without range jump suppression the time history would be:</p><p>.., 179°, 180°, -179°, ..</p><p>i.e. with a 360° jump. To avoid this jump OrcaFlex adds or subtracts multiples of 360° to give the best continuation</p><p>of the previous value. So in this example it adds 360° to the -179° value and hence reports:</p><p>.., 179°, 180°, 181°, ..</p><p>This addition is valid since 181° and -179° are of course identical headings.</p><p>Note that this means that angle time history results can go outside the range -360° to +360°.</p><p>Spectral Density</p><p>From any time history graph you can use the pop-up menu to obtain the spectral density graph for that time history.</p><p>The curve shown on the graph is the one-sided power spectral density (PSD) per unit time of the sampled time</p><p>history, obtained using the Fourier Transform. The fundamental frequency is specified on the General data form.</p><p>Notes: Using the Fourier Transform to estimate the PSD inevitably introduces 'noise' or 'leakage' to the</p><p>spectrum. To reduce the leakage the time history is partitioned into a number of overlapping</p><p>periods. The PSDs are calculated for each period and then averaged to give the reported PSD which</p><p>has the effect of smoothing the resulting PSD.</p><p>User Interface, Results w</p><p>72</p><p>This smoothing technique is only applied if there is more than 200s of data in the time history.</p><p>Empirical Cumulative Distribution</p><p>From any time history graph you can use the pop-up menu to obtain the empirical cumulative distribution graph for</p><p>that time history. This graph shows what proportion of the samples in the time history are less than or equal to a</p><p>given value.</p><p>These graphs are sometimes referred to as Exceedence Plots since they can sometimes be used to estimate the</p><p>probability that the variable will exceed a given value.</p><p>Warning: The samples in a time history are not independent. They have what is called 'serial correlation',</p><p>which often affects the accuracy of statistical results based on them.</p><p>Rainflow half-cycle Empirical Cumulative Distribution</p><p>From any time history graph you can use the pop-up menu to obtain the rainflow half-cycle empirical cumulative</p><p>distribution graph for that time history. The curve on this graph is produced in the following way:</p><p>1. The time history is analysed using the rainflow cycle-counting algorithm. For details of this algorithm see the</p><p>paper by Rychlik.</p><p>2. The rainflow algorithm produces a list of half-cycles associated with the time history. The empirical cumulative</p><p>distribution of these half-cycles is then plotted.</p><p>3.9.9 Range Graphs</p><p>Range graphs are only available for a selection of variables and they are only available for Lines. They show the</p><p>values the variable took,</p><p>during a specified part of the simulation, as a function of arc length along the Line. In</p><p>particular:</p><p> Range graphs show the minimum, mean and maximum values that the variable took during the specified part of</p><p>the simulation with the exception that the Line Clearance range graphs only show the minimum value.</p><p> Effective tension range graphs have extra curves showing the segment Euler load and the Allowable Tension</p><p>value (as specified on the Line Types data form).</p><p> Bend Moment range graphs have an extra curve showing the maximum permitted bend moment</p><p>(EI / Minimum Bend Radius specified on the Line Types data form).</p><p> Curvature range graphs have an extra curve showing the maximum permitted curvature (the reciprocal of the</p><p>Minimum Bend Radius specified on the Line Types data form).</p><p> Stress range graphs show the Allowable Stress (as specified on the Line Types data form).</p><p> A Standard Deviation curve can also be added to a range graph – to do this edit the graph's properties (by</p><p>double clicking on the graph) and set the Standard Deviation curve's visible property (by default the curves are</p><p>not visible). Two curves are then drawn, at Mean ± xσ, where x is a user chosen value and σ is the standard</p><p>deviation. The standard deviation is calculated from all the samples that lie in the simulation period chosen for</p><p>the graph.</p><p>Warning: Be careful not to assume that 95% of the data lie in the interval Mean ± 2σ. This common guideline</p><p>is based on the assumption that the data are sampled from a Normal (i.e. Gaussian) distribution.</p><p>To obtain a Range Graph:</p><p> Select Range Graph on the Results form.</p><p> Select the object required.</p><p> Select the arc lengths required. This can be the entire line, a selected arc length range, or a selected line section.</p><p> Select the variable required (see Selecting Variables).</p><p> Select the period required.</p><p> CLICK the Graph button.</p><p>Range graphs are displayed in Graph Windows and they are "live" – i.e. they are regularly updated during the</p><p>simulation. You can therefore set up one or more graph windows at the start of a simulation and watch the graphs</p><p>develop as the simulation progresses. If you reset the simulation then the curves will be removed but the graphs will</p><p>w User Interface, Results</p><p>73</p><p>remain, so you can adjust the model and re-run the simulation and the graphs will then be redrawn. Graphs are</p><p>automatically deleted if the object that they refer to is removed, for example by loading a new model.</p><p>Range Jump Suppression</p><p>Just as it does for Time History and XY Graphs, OrcaFlex applies range jump suppression for range graphs of angles.</p><p>3.9.10 Offset Graphs</p><p>These graphs are available only after a multiple statics calculation has been done and only for the offset vessel. The</p><p>following variables are plotted against offset distance:</p><p>Restoring Force</p><p>The magnitude of the horizontal component of the total force applied to the vessel by the attached Lines or other</p><p>objects. Note that this force is not necessarily in the offset direction.</p><p>Vertical Force</p><p>The vertically downwards component of the total force applied to the vessel by the attached Lines or other objects.</p><p>Yaw Moment</p><p>The moment, about the vertical, applied to the vessel by the attached Lines or other objects.</p><p>Worst Tension</p><p>The largest tension in any segment of any Line connected to the vessel.</p><p>To obtain an Offset Graph:</p><p> Select Offset Graph on the Results form.</p><p> Select the offset vessel.</p><p> Select the offset direction required.</p><p> Select the variable required.</p><p> CLICK the Graph button.</p><p>3.9.11 Spectral Response Graphs</p><p>These graphs are available only if you have run a response calculation wave. The graph is only available once the</p><p>simulation has been completed.</p><p>The graph plots the calculated RAO for the selected variable on the Y axis and wave frequency on the X axis.</p><p>To obtain a Spectral Response Graph:</p><p> Select Spectral Response Graph on the Results form.</p><p> Select the object required.</p><p> Select the variable required (see Selecting Variables). More than one variable can be selected.</p><p> CLICK the Graph button.</p><p>3.9.12 Extreme Value Statistics Results</p><p>There is often a requirement to predict the extreme responses of a system, for example to determine the likelihood</p><p>of a load exceeding a critical value that may lead to failure. Such values are needed when using standards such as</p><p>DNV-OS-F201 and API RP 2SK.</p><p>OrcaFlex can estimate extreme values for any given result variable by analysing the simulated time history of the</p><p>variable using extreme value statistical methods. You may, for instance, perform a mooring analysis in an irregular</p><p>sea-state and then estimate the maximum mooring line tension for a 3-hour storm.</p><p>The statistical theory for this estimation is well-established and is described in the theory section. The procedure is</p><p>essentially this:</p><p> You select the statistical distribution to be used to model the distribution of extremes. See Data below.</p><p> OrcaFlex estimates the distribution model parameters that best fit the simulation time history of the variable.</p><p>User Interface, Results w</p><p>74</p><p> OrcaFlex uses the fitted distribution to estimate and report the required extreme statistic (e.g. return level), for</p><p>a specified period of exposure. See Results below.</p><p> OrcaFlex provides diagnostic graphs that you should use to judge the reliability of the results.</p><p>The Extreme Value Statistics Results form is designed to lead you through this process.</p><p>When you open the Extreme Value Statistics Results form, for a selected results variable, you will come first to the</p><p>Data page, where you will select the distribution. Moving then to either of the other pages (Results or Diagnostic</p><p>Graphs) will cause OrcaFlex to carry out the estimation part of the procedure. The Diagnostic Graphs assist in</p><p>testing the model. The Results page reports the estimated statistics, e.g. the return value for the specified period, the</p><p>estimation uncertainty inherent in that value etc.</p><p>Data</p><p>For convenience, the time history result graph is reproduced on the Data page. The data required for the fitting of</p><p>the model are entered on this page, and are as follows.</p><p>Distributions</p><p>These fall into two groups, according to the statistical method with which they are applied. For details see the</p><p>Extreme Value Statistics Theory section.</p><p> Rayleigh distribution. This method assumes that the variable is a stationary Gaussian process. This is perhaps a</p><p>reasonable assumption for waves, particularly in deep water, and for responses which are approximately linear</p><p>with respect to wave height. However, for many other variables of interest, the Gaussian assumption is invalid</p><p>and leads to poor estimates of extreme values.</p><p> Weibull and Generalised Pareto (GPD) distributions. These distributions are both fitted using the maximum</p><p>likelihood method. Historically, the Weibull distribution has often been used for marine systems, but the</p><p>Generalised Pareto is preferred by the extreme value statistics community because of its sound mathematical</p><p>foundations.</p><p>Extremes to analyse</p><p>Specifies whether maxima (upper tail) or minima (lower tail) are to be analysed.</p><p>Threshold and Decluster Period</p><p>These data are only required when using the Weibull and GPD distributions, which are fitted to extremes of the time</p><p>history and those extremes are selected using the peaks-over-threshold method with (optional) declustering.</p><p>The threshold controls the peaks-over-threshold method. This allows you to control the extent to which the</p><p>analysis is based on only the extreme values in the data (the tail of the distribution).</p><p>The decluster period controls the declustering. This helps avoid or reduce any statistical dependence between the</p><p>extreme data values used in the analysis. It can be set to one of the following:</p><p> Zero, in which case no declustering will be done, and all values above the specified threshold will be included.</p><p>This is generally not</p><p>recommended since the values are unlikely to be independent.</p><p> A positive value. In this case OrcaFlex will break the sequence of time history values into clusters of successive</p><p>values that stay above the threshold. It will then decluster by merging successive clusters that are separated by</p><p>periods (during which the variable is less than the threshold) that last no longer than the specified decluster</p><p>period. The most extreme value of each of the resulting merged clusters will then be included in the analysis.</p><p> '~'. This special value may be used to tell OrcaFlex to take the clusters to be the groups of values between</p><p>successive up-crossings of the mean value (or down-crossings if analysing lower tail). The most extreme value</p><p>of each such cluster will then be included in the analysis, but ignoring any that do not exceed the threshold.</p><p>The threshold is drawn on the time history graph, to help visualise its value relative to the extremes of the data. The</p><p>number of data points that will be included in the analysis (after the threshold and declustering have been done) is</p><p>also displayed. This helps with setting the threshold and decluster period.</p><p>The best value for the threshold is one that strikes a balance between a not-extreme-enough value (which will</p><p>increase the number of data points fitted but may give biased fitting by allowing less extreme values to influence the</p><p>fitting too much), and a too-extreme value (which will fit to only the more relevant extreme data points, but may</p><p>give very wide confidence intervals if there are too few such extremes in the data).</p><p>w User Interface, Results</p><p>75</p><p>Results</p><p>The following data items, found on the Results page, do not affect the fitting of the statistical model. Rather, they are</p><p>applied to the fitted model to obtain the reported results.</p><p>Rayleigh</p><p>Storm duration is the return period for which the return level is reported. The length of the simulation, relative to</p><p>this duration, will determine the accuracy of the estimate for the return level.</p><p>Risk factor is the probability of exceeding (or falling below, for lower tail) the estimated extreme value. For</p><p>example, you may ask for the 3-hour extreme value that is exceeded with a probability of 0.01 (i.e. a risk factor of</p><p>1%).</p><p>Weibull and GPD</p><p>Storm duration is defined as for the Rayleigh distribution.</p><p>The maximum likelihood fitting procedure used for these distributions allows the estimation of a confidence</p><p>interval for the return level, for a specified confidence level. OrcaFlex reports this estimated confidence interval in</p><p>addition to the estimated return level.</p><p>The reported return level is defined to be the level whose expected number of exceedences in the specified storm</p><p>duration is one. The fitted values of the model parameters and corresponding standard errors are also reported.</p><p>Note: For some values of storm duration (usually small values) it might not be possible to calculate the</p><p>return level. This is indicated by the value 'N/A' (meaning 'not available'). Similarly, for some</p><p>combinations of storm duration and confidence level, the calculation may fail to determine the</p><p>confidence limits, and again these are then denoted by 'N/A'.</p><p>Diagnostic Graphs</p><p>The diagnostic graphs will help you to assess the goodness-of-fit of the model, and how appropriate or not the fitted</p><p>distribution is. They should be interpreted together, not in isolation, as follows.</p><p> The Quantile Plot displays quantiles of the empirical data plotted against model quantiles. If the model is a</p><p>good fit, then the points should lie close to the superimposed 45° diagonal line, and any significant departure</p><p>from this (especially a systematic one, for example an obvious trend away from the diagonal) indicates poor</p><p>model fit. The vertical lines, drawn through each point, are pointwise 95% tolerance intervals and may be</p><p>used as a guide to deciding whether any departure from the diagonal is significant. If all the vertical lines</p><p>intersect the diagonal line, then the modelled values are probably sufficiently close to the empirical value not to</p><p>be of concern. If, however, a number of the vertical lines fail to reach the diagonal, then that may raise concerns</p><p>about the validity of the fitted model.</p><p> The Return Level Plot shows return level against return period (i.e. storm duration), with the latter on a</p><p>logarithmic scale to highlight the effect of extrapolation. The central line on the graph is the return level for the</p><p>fitted model, and the pair of outer lines the corresponding pointwise 95% confidence limits. The points are the</p><p>empirical return levels, based upon the data, and should lie between the confidence limits if the model fits the</p><p>data well. As with the quantile plot, a significant number of points contravening these limits indicates poor</p><p>model fit. Again, OrcaFlex may sometimes be unable to determine the confidence limits for some return periods</p><p>– this may result in gaps in the confidence limit lines, or even in their not appearing at all.</p><p>An example of diagnostics graphs indicating a good model fit is shown below:</p><p>User Interface, Results w</p><p>76</p><p>Figure: Diagnostics graphs for a good model fit</p><p>If either of these graphs indicates a poor model fit, then you should reconsider the entries on the data page:</p><p> Distribution. The distribution may be inappropriate – the data may simply not conform to the selected</p><p>distribution.</p><p> Threshold. The threshold may be too low, hence including too many points which are not in the tail of the</p><p>distribution; or too high, resulting in too few data points for the analysis and consequent large variation in the</p><p>results.</p><p> Decluster period. This may be too long (so too few data points), or too short (so successive data points might</p><p>not be independent).</p><p>Automation</p><p>The extreme value statistics capabilities can be automated in a number of different ways.</p><p>OrcaFlex spreadsheet</p><p>The OrcaFlex spreadsheet post-processing facility supports analysis using the Rayleigh distribution via the Rayleigh</p><p>Extremes command. The Weibull and GPD distributions are not available in the current version due to the</p><p>complexity of threshold selection.</p><p>OrcaFlex programming interface</p><p>The C/C++, Delphi, Python and MATLAB programming interfaces to OrcaFlex all support automation of extreme</p><p>value statistics. As with all other functionality, the Python and MATLAB interfaces are the easiest to use.</p><p>The full analysis capability is available via the programming interface. That is, in contrast to the OrcaFlex</p><p>spreadsheet, analysis using the Weibull and GPD distributions is available.</p><p>3.9.13 Presenting OrcaFlex Results</p><p>OrcaFlex users often wish to show their OrcaFlex results in a slide presentation prepared using a presentation</p><p>program such as Microsoft PowerPoint. Here are some tips on how this can be done.</p><p>Graphs</p><p>Graphs can be transferred from OrcaFlex to presentation programs by simple copy + paste.</p><p>w User Interface, Graphs</p><p>77</p><p>Note: In PowerPoint, instead of using Paste, it is better to use Paste Special (from the Edit menu) and</p><p>then select the Enhanced Metafile. This gives better resolution.</p><p>Replays</p><p>Replays can be transferred by exporting to an AVI file and then importing that video clip file into the presentation</p><p>program.</p><p>An XVID encoded AVI file (and possibly other codecs) added to Microsoft PowerPoint slides as a Movie Object may</p><p>not play correctly (displaying a blank screen on replay, or the video only appearing in full screen mode). To avoid</p><p>these problems, an XVID AVI file needs to be inserted as a Video Clip Object. This can be done in two ways:</p><p>1. Drag and Drop the AVI file onto the PowerPoint slide, or</p><p>2. From the PowerPoint menu, choose Insert | Object. Select 'Create from file' and Browse to your file (do not</p><p>select the 'Link' option).</p><p>To set options such as auto repeat, right-click on the image in the slide, then select Video Clip Object | Open, this</p><p>displays the video player window and</p><p>menus.</p><p>The Video Clip Object links to the AVI file (it is not embedded within PowerPoint) so the file location needs to be</p><p>accessible when running the presentation. The computer running the presentation must also have the XVID codec</p><p>installed.</p><p>Note: Resizing video clips (after pasting into your presentation) will introduce aliasing (re-digitisation</p><p>errors) so it is best to set the OrcaFlex 3D View window to the required size before you export the</p><p>video.</p><p>Video Clips of OrcaFlex in Use</p><p>Your presentation can even show video clips of OrcaFlex in use, illustrating how the program is used. However, it is</p><p>rather harder to generate the required video files. We recommend using software called Camtasia</p><p>(www.techsmith.com) to record video clips showing OrcaFlex in use.</p><p>3.10 GRAPHS</p><p>When you request results in graphical form, they are presented in Graph Windows. You can open several</p><p>simultaneous graph windows, showing different results, and tile them on the screen together with 3D Views and</p><p>text results windows. To adjust a graph's properties (range of axes, colours, etc.) see Modifying Graphs.</p><p>Graphs have a pop-up menu that provides the following facilities.</p><p> Use Default Ranges.</p><p> Copy copies the graph to the clipboard, from where you can paste it into other applications.</p><p> Values.</p><p> Spectral Density.</p><p> Empirical Cumulative Distribution.</p><p> Rainflow half-cycle Empirical Cumulative Distribution.</p><p> Export enables you to export the graph to a metafile or bitmap file.</p><p> Print facilities and the Monochrome Output preference.</p><p> Properties.</p><p>Graphs of simulation results are updated automatically as the simulation progresses. Also, they are kept even if you</p><p>reset the simulation, so once you have set up a set of interesting graphs you can edit the model and re-run the</p><p>simulation to see the effect of changing the model.</p><p>You can also set up results graphs when in reset state, prior to running a simulation – the graph will be empty</p><p>initially and will grow as the simulation progresses. Note that we do not recommend this for graphs of line</p><p>clearance, however, since updating them can significantly slow down the simulation.</p><p>The workspace feature provides a very powerful way of managing collections of related graphs.</p><p>When a replay is in progress the replay time is indicated on both Time History and XY graphs.</p><p>http://www.techsmith.com/</p><p>User Interface, Graphs w</p><p>78</p><p>Figure: Replay time indicator on a Time History Graph (vertical line at Time=16s) and on an XY</p><p>Graph (grey cross in bottom right of the graph).</p><p>The replay time indicator on a Time History graph can be directly manipulated using the mouse. With the CTRL key</p><p>pressed you simply click on a Time History graph and the indicator moves to where you have clicked. Any open 3D</p><p>Views are updated to show the new replay time. Similarly, with the CTRL key pressed you can click and then drag the</p><p>indicator. This direct manipulation of the replay time indicator is designed to help understand and visualise how</p><p>your model is behaving at key moments of the simulation.</p><p>Printing Graphs</p><p>To print a graph, use the File | Print menu item. When printing to a monochrome printer you will get the best results</p><p>by setting the Monochrome Output preference – this is set by default when the program is first installed.</p><p>Copy and Paste with graphs</p><p>You can also copy a graph to the clipboard – simply select the graph window by CLICKING on it and then using the</p><p>Edit | Copy menu item. From the clipboard you can then paste it into another application, for instance into a word</p><p>processor document. Graphs can also be exported as Windows metafiles, use the File | Export menu item. Metafiles</p><p>can be imported into many Windows programs, such as word processors, spreadsheets, graphics packages etc.</p><p>Note: When copying a graph to the clipboard, the size of the graph window you copy from has an effect</p><p>on how the text label fonts appear when the graph is pasted into another application. For example,</p><p>if you are copying a graph to a Word Processor and want the graph to be full page size, then the</p><p>graph window should be made large on screen (e.g. maximised). If you want a number of graphs on</p><p>one page of a document then the graph should be smaller on screen – try tiling or cascading the</p><p>windows (see the Window menu). By experimenting with various differently sized graphs it should</p><p>be possible to arrange for the fonts to appear as you wish.</p><p>3.10.1 Modifying Graphs</p><p>You can zoom into a graph by holding down the ALT key and dragging a box around the area that you want the graph</p><p>to display. When you release the mouse button the region selected will be expanded to fill the graph. Mouse</p><p>shortcuts can also be used: CTRL+wheel to zoom, SHIFT+drag to pan. If you want to reverse this process then right</p><p>click the mouse and choose Use Default Ranges from the pop-up menu.</p><p>You can also change the appearance of a graph by double clicking on the graph or by selecting Properties from the</p><p>graph's pop-up menu. A form is then shown which allows you to change various aspects of the graph, as follows:</p><p>Content/html/Menus__File_Menu.htm</p><p>w User Interface, Spreadsheets</p><p>79</p><p>Axes</p><p>You can set the range, the tick spacing and the number of small ticks. The Use Default Tick Spacing button sets the</p><p>tick spacing and the number of small ticks to sensible default values based on the range. This is useful if you want to</p><p>set the range to a specific value and want the tick spacing to be set automatically.</p><p>Labels</p><p>You can alter the text and fonts of the axis and tick labels.</p><p>Curves</p><p>You can control the line properties and visibility for each curve on the graph.</p><p>Legend</p><p>The legend is a key showing which curve is which. It only appears on graphs that have multiple curves, e.g. range</p><p>graphs. You can control whether the legend is shown and if so where and using what font. Note that the legend</p><p>includes all the curves, even if some of them may not be visible at the time.</p><p>Intercepts</p><p>Intercepts are lines, like the axes, that go right across the graph. In fact the X and Y axes themselves are considered</p><p>to be intercepts. You can add more intercepts, for example to mark things like stage start times, and you can control</p><p>their position and style.</p><p>Save As Default</p><p>Changes to a graph's properties normally only apply to that graph. But for general settings (fonts etc.) you can also</p><p>click the Save As Default button. OrcaFlex then remembers the current settings for use with future graphs.</p><p>3.11 SPREADSHEETS</p><p>Some numerical results (e.g. obtained with the Values button on the Results form) appear in an Excel compatible</p><p>spreadsheet. The spreadsheet is read-only. If you wish to modify or extend it you must first save it as described</p><p>below.</p><p>Printing, Copying and Exporting Spreadsheets</p><p>To print the spreadsheet right click and select Print, but remember that OrcaFlex time histories are normally quite</p><p>long and will therefore produce many pages. If necessary, you can first adjust the printer setup using File | Printer</p><p>Setup.</p><p>You can also easily transfer the results to other applications by either:</p><p> Copy and paste via the Windows clipboard. Select the block to be transferred and press CTRL+C.</p><p> Saving to file. Choose Export from the popup menu to save as Excel format (.xls), comma separated values (.csv)</p><p>or as tab delimited text (.txt).</p><p>3.12 TEXT WINDOWS</p><p>Simple text windows are used for some reports – see below. To print a text window, use the File | Print menu. You</p><p>can also copy text to the clipboard – simply select a region of text and then use the Edit | Copy menu item (or press</p><p>CTRL+C). From the clipboard you can then paste it into another application, for instance into a word processor</p><p>document. Alternatively, you can export the text to a file by using the File | Export menu item. The resulting text file</p><p>can then be imported into your word processor.</p><p>Statics Progress Window</p><p>During a Statics Calculation, the progress of the</p><p>calculation is shown in the message box on the status bar. However</p><p>the messages are also sent to a text window that is normally minimised. This window may be viewed by clicking on</p><p>the message box during statics, or by selecting the Window | Statics Progress menu item if you wish to watch the</p><p>process more closely. Like other text windows it may be printed, copied or exported, as described above.</p><p>3.13 WORKSPACES</p><p>It is common to have many windows (3D View, graph or spreadsheet) open within OrcaFlex. The workspace facility</p><p>is designed to help manage these windows.</p><p>Content/html/Menus__File_Menu.htm</p><p>User Interface, Comparing Data w</p><p>80</p><p>Workspace files</p><p>A collection of view, graph or spreadsheet windows can be saved using the Workspace | Save Workspace menu item.</p><p>This creates a text file with the .wrk file extension containing a specification of the current window layout. The</p><p>workspace can be restored at any time with the Workspace | Open Workspace menu item. This can give significant</p><p>time savings if you wish to look at a number of different results windows for a large number of OrcaFlex models.</p><p>Note that the contents of the windows are not saved to the workspace file, just a logical description of the window.</p><p>For example, suppose you saved a workspace containing a graph of Effective Tension of a Line called Riser. If you</p><p>then loaded a different simulation file and open that workspace then you would see the Effective Tension of the Line</p><p>called Riser in the new simulation file and not the simulation filed open when the workspace was saved. This means</p><p>that you can look at the same collection of results for any number of simulation files.</p><p>Workspace files are not limited to simulation files – static results and multiple statics results can also be saved.</p><p>Default workspaces</p><p>As an alternative to loading a workspace by using the Workspace menu items you can associate default workspaces</p><p>with either individual simulation files or with entire directories.</p><p> If you define a default workspace for a simulation file then the workspace is restored whenever you open that</p><p>same simulation file.</p><p> If you define a default workspace for a directory then the workspace is restored whenever you open any</p><p>simulation file in that directory.</p><p>Getting the most out of workspaces</p><p>We recommend that you save your workspace files in the same directory as the OrcaFlex files. If you do so then the</p><p>workspace file will appear in the Most Recent Files list on the Workspace menu.</p><p>Workspace files can be very useful if you are sending simulation files to another person. By including a workspace</p><p>file with the results of interest you can be sure that they will view the correct information. This can be particularly</p><p>valuable when sending files to someone who is not an experienced OrcaFlex user. This can even be useful when</p><p>sending files to Orcina for software support because they contain a precise specification of the results you are</p><p>interested in.</p><p>3.14 COMPARING DATA</p><p>The Compare Data menu item opens the Compare Data form, which allows you to find differences between the data</p><p>in two OrcaFlex files.</p><p>The comparison is done using a user-provided compare program, so when you first use this facility you need to</p><p>configure OrcaFlex to tell it which compare program that you want to use; see Configuration below.</p><p>You can then compare files as follows:</p><p> On the Files page, specify the two files that you wish to compare. These can be data or simulation files.</p><p> Click the Compare button.</p><p> OrcaFlex then saves the data from the two files to temporary text files and then runs the user-specified compare</p><p>program to compare those text files.</p><p>As an alternative to comparing two data files on disk you can optionally choose to compare the currently loaded</p><p>model with a single file on disk.</p><p>Configuration</p><p>On the Configuration page you need to tell OrcaFlex the text file compare program that you want to use, and how to</p><p>use it. The compare program must be a program that can compare text files passed to it through the command line.</p><p>Many such programs are available on the web; we at Orcina have a preference for WinMerge.</p><p>Compare Program</p><p>This is the compare program's executable file name. You can specify either the full path, or just the file name if the</p><p>executable file resides in a directory which is on your system path.</p><p>If no program is specified OrcaFlex uses a very basic, built-in, compare facility.</p><p>http://winmerge.org/</p><p>w User Interface, Preferences</p><p>81</p><p>Command Line Parameters</p><p>This defines the command line parameters that are passed to the compare program. OrcaFlex replaces the special</p><p>strings %1 and %2 with the file names of the temporary text files.</p><p>OrcaFlex also replaces special strings %name1 and %name2 with readable names describing the two files or objects</p><p>that are being compared. Not all compare programs have the capability of assigning readable names and just use the</p><p>file name, so the use of this facility is optional.</p><p>For most compare programs the default setting of %1 %2 will be sufficient. Otherwise you will need to consult the</p><p>documentation of your compare program.</p><p>If you are using WinMerge then we recommend using the following: /e /x /s /dl %name1 /dr %name2 %1 %2</p><p>3.15 PREFERENCES</p><p>OrcaFlex has a number of settings that can be customised to suit the way that you work. The majority of settings can</p><p>be adjusted in the Preferences form, which is accessed by using the Tools | Preferences menu item.</p><p>3D View Preferences</p><p>Minimum Drag Distance</p><p>Object positions are not updated until the mouse has been dragged at least this distance (in pixels). This prevents</p><p>accidental changes to object positions. To make a small movement, drag away and then back again, or edit the</p><p>coordinate directly in the object's Edit Form.</p><p>View Rotation Increment</p><p>Each CLICK on a Rotate View button increments or decrements View Azimuth or Elevation by this amount.</p><p>Refresh Rate</p><p>During a simulation calculation all 3D View and Graph windows are updated at this rate. Selecting a faster rate</p><p>allows you to see the behaviour of the simulation more clearly at the expense of performance. Set a slow Refresh</p><p>Rate to give the numerical calculation more processor time.</p><p>Background Colour</p><p>This sets the background colour of all 3D View windows.</p><p>Locate Object Method</p><p>Can be either Flash object or Hide other objects. It determines what method the Locate action in the model</p><p>browser uses.</p><p> When the Flash object preference is set then the Locate action repeatedly draws and hides the object on the 3D</p><p>View, like a blinking cursor.</p><p> When the Hide other objects preference is set then the Locate action temporarily hides all other objects.</p><p>Normally the default setting of Flash object is sufficient to locate objects. However, if the model you are searching</p><p>for is obscured by other objects then this method may not help you to locate the object. In this case you should use</p><p>the Hide other objects preference.</p><p>3D View Axes Preferences</p><p>View Axes</p><p>The view axes show the same directions as the global axes, but are drawn in the top right hand corner of 3D views,</p><p>rather than at the global origin. Can also be set from the View menu.</p><p>Scale Bar</p><p>Determines whether a scale bar is drawn in 3D views. Can also be set from the View menu.</p><p>Note: The Scale Bar is not drawn for shaded graphics views because it would be meaningless due to</p><p>perspective.</p><p>User Interface, Preferences w</p><p>82</p><p>Global Axes</p><p>Determines whether the global axes are drawn, at the model's global origin (0,0,0). Can also be set from the View</p><p>menu.</p><p>Environment Axes</p><p>Determines whether the wave, current and wind directions are drawn in the 3D view. When multiple wave trains</p><p>are present the first wave train is taken to be the dominant one and is drawn using sea surface pen, whereas the</p><p>other wave trains' directions are drawn in the secondary wave direction pen. Can also be set from the View menu.</p><p>Local Axes</p><p>Determines</p><p>whether the local axes for vessels, buoys and line ends are shown. Drawing the local axes on the 3D</p><p>view helps you check the orientations of these objects. This preference can also be set from the View menu.</p><p>Note: Local Axes are not drawn for shaded graphics views.</p><p>Node Axes</p><p>Determines whether axes for line nodes are shown. This preference can also be set from the View menu.</p><p>Out of Balance Forces</p><p>If selected, then in the static analysis (not during the simulation) there are extra lines drawn on the 3D view,</p><p>representing the out of balance force acting on each vessel and buoy. This preference is sometimes useful for static</p><p>analysis, since it enables you to see how far a buoy or vessel is from being in equilibrium. This preference can also</p><p>be set from the View menu.</p><p>The force is drawn as a line, starting at the force's effective point of application, and whose length represents the</p><p>size of the force. The scaling is piecewise linear and based on the View Size of the 3D view. Lines up to ViewSize/2</p><p>long mean forces up to 10 force units and lines from ViewSize/2 to ViewSize mean forces from 10 to 1000 force</p><p>units.</p><p>Note: Out of Balance Forces are not drawn for shaded graphics views.</p><p>Video Preferences</p><p>The video preferences allow you to control the compression algorithm used for exported video. The software which</p><p>performs this compression is called a codec. Because the different graphics modes produce very different images</p><p>they require different types of codec.</p><p>Shaded Graphics Codec</p><p>The run-length encoding which works well for wire frame graphics is not suitable for shaded replays and in fact</p><p>there is no suitable built-in codec in Windows. We would recommend using an MPEG-4 codec of which many are</p><p>available. In our experience the freely available (licensed under the GPL) XVID codec performs very well. The</p><p>Shaded Graphics topic has more information about the XVID codec.</p><p>Another reasonable choice is the Windows Media Video 9 codec, which is identified by the code WMV3. This codec</p><p>produces lower quality videos than XVID for the same video file size, but does have the advantage that the videos</p><p>should work on almost all Windows machines without the need for codec installation. Details on how to download</p><p>this codec can be found at: www.orcina.com/Support/ShadedGraphics.</p><p>You can choose to use other codecs that are installed on your machine. Should you do so then you must also specify</p><p>the following information:</p><p> Codec 4 character code: Codecs are identified by unique codes, 4 characters long. Good alternatives to XVID</p><p>and WMV3 include DIVX, the 3ivx codec (character code 3IV2).</p><p> Padding: MPEG-4 codecs commonly require round number frame sizes (width and height in pixels). For</p><p>example XVID requires frame sizes to be multiples of 8. When OrcaFlex exports the video it ensures that the</p><p>frame sizes are a multiple of this number. If you are unsure of what number to use for your codec then we</p><p>recommend trying 8 which usually works.</p><p> Colour depth: Some MPEG-4 codecs require a specific colour depth. Again, if you are unsure of what value to</p><p>use then we recommend trying 32 bit or 16 bit colour depth.</p><p>http://www.orcina.com/Support/ShadedGraphics#VideoExport</p><p>http://www.divx.com/</p><p>http://www.3ivx.com/</p><p>w User Interface, Printing and Exporting</p><p>83</p><p>Wire Frame Graphics Codec</p><p>Run-length encoding is the default setting and is usually the best choice. This codec offers good compression rates</p><p>for OrcaFlex wire frame video. The AVI files produced using this codec can be played on most Windows PCs.</p><p>If you choose Uncompressed then each frame of the video is stored as an uncompressed bitmap. This means that</p><p>the AVI file produced can be extremely large.</p><p>Output Preferences</p><p>Printer Margins</p><p>These set the Left and Top margins used on printouts.</p><p>Monochrome Output</p><p>If this is checked then external output (copying to the clipboard, exporting metafiles and printing) is in black and</p><p>white. This is useful with black and white printers, since otherwise pale colours may be drawn in very light grey and</p><p>may be hard to see.</p><p>Messages Preferences</p><p>A number of OrcaFlex warning messages can be disabled by checking Don't show this message again on the warning</p><p>message form. Once a message has been disabled, it will not be shown again. These messages can be re-enabled by</p><p>checking the appropriate box on this page.</p><p>Miscellaneous Preferences</p><p>Show Splash Screen</p><p>Determines whether OrcaFlex displays its splash screen when the program starts.</p><p>Batch Auto Save</p><p>If this is enabled then simulations run in batch mode are automatically stored to simulation files at the specified</p><p>regular Auto Save Interval. This is useful if your computer is prone to failure (for example because of overnight</p><p>power failures) since the part-run simulation file can be loaded and continued, rather than having to re-run the</p><p>whole simulation from scratch. The Auto Save Interval should be neither too short, since then the program will then</p><p>waste a lot of time repeatedly storing away the results, nor too long, since then a lot of simulation work will be lost if</p><p>a failure occurs.</p><p>3.16 PRINTING AND EXPORTING</p><p>The Print / Export form is accessed using either the File | Print or the File | Export menu item and allows you to</p><p>choose one or more of the following items to be printed or saved to file:</p><p> The model data. Vessel Types often have very large amounts of data, much of which may not apply to the</p><p>current model, so OrcaFlex offers you the option of printing all the vessel type data or only the data that is in</p><p>use.</p><p> Any 3D Views, Graphs, Spreadsheets and Text Windows currently on display.</p><p>Note: Graphs are printed as large as possible whilst maintaining aspect ratio.</p><p>Content/html/Menus__File_Menu.htm</p><p>w Automation, Introduction</p><p>85</p><p>4 AUTOMATION</p><p>4.1 INTRODUCTION</p><p>OrcaFlex provides several important facilities for automating and post-processing work:</p><p> OrcaFlex is supplied with a special Excel spreadsheet which enables you to automate the extraction of</p><p>simulation results into your own spreadsheet. You can then use the normal Excel calculation facilities to do your</p><p>own customised post-processing and graphing.</p><p> The Batch Processing facility enables you to run a set of simulations in unattended mode, for example as an</p><p>overnight job. The simulations can either be of pre-prepared data files, or else can be specified by a batch script</p><p>file that specifies the simulation as variations on a base data file. The OrcaFlex Spreadsheet mentioned above</p><p>also has facilities for automating the production of batch script files and text data files.</p><p> OrcaFlex includes a well-documented programming interface called OrcFxAPI (short for OrcaFlex Application</p><p>Program Interface). See the OrcFxAPI help file for details. OrcFxAPI is a Windows dynamic link library (DLL)</p><p>that is installed when you install OrcaFlex, and which provides facilities for setting data, calculating static</p><p>positions and extracting results from those calculations or from pre-run simulation files. For example you can</p><p>write programs to automate post-processing or that use OrcaFlex as a 'statics calculation engine'. One important</p><p>example application of this is for real-time monitoring of pipes, moorings etc. For further information or to</p><p>discuss possible applications of OrcFxAPI, please contact Orcina.</p><p>4.2 BATCH PROCESSING</p><p>4.2.1 Introduction</p><p>Simulations, script files, post processing spreadsheets and fatigue analyses can all be run in unattended mode, by</p><p>using the Calculation | Batch Processing menu item. This command opens a form that allows you to set up a list of</p><p>jobs that are to be run. The list can include any number and mixture of the following types of job:</p><p>1. Static analysis of pre-prepared OrcaFlex data files (.dat or .yml). OrcaFlex opens the data file, performs the static</p><p>analysis and then saves the results in a simulation file with the same name as the data file, but with a .sim</p><p>extension.</p><p>2.</p><p>Dynamic analysis of pre-prepared OrcaFlex data files (.dat or .yml). OrcaFlex opens the data file, performs the</p><p>static analysis, runs the dynamic simulation and then saves the results in a simulation file with the same name</p><p>as the data file, but with a .sim extension.</p><p>3. Partially-run OrcaFlex simulation files (.sim). OrcaFlex opens the simulation file, finishes the dynamic</p><p>simulation and then saves the completed simulation, overwriting the original file.</p><p>4. A batch script file (.txt). This is a text file which contains OrcaFlex script commands. OrcaFlex opens the script</p><p>file and obeys the commands in turn. The most common use of script files is to perform a series of systematic</p><p>variations on a base data file.</p><p>5. A fatigue analysis file (.ftg or .yml). OrcaFlex performs the fatigue analysis and saves the results to a binary .ftg</p><p>file. In addition the results tables are saved to an .xls spreadsheet.</p><p>6. An OrcaFlex Spreadsheet (.xls or .xlsx). OrcaFlex will process all Instructions sheets in the Excel workbook. Note</p><p>that if the spreadsheet's "Contains Dependencies" options is checked (or the spreadsheet is pre OrcaFlex v9.4)</p><p>then the workbook will be processes as a single job using a single thread. If it isn’t checked, then each</p><p>instructions sheet will be broken down into multiple load cases which are individually added to the batch and</p><p>may be processed simultaneously.</p><p>Note: If you wish to use Excel for any reason while OrcaFlex is processing spreadsheets within a batch it</p><p>is important that you open Excel first, then open the file you wish to work on. The reason for this is</p><p>that when you double click an Excel file, Windows will try to use the copy of Excel OrcaFlex has</p><p>claimed, resulting in unpredictable failures.</p><p>When adding data files (.dat or .yml) you need to specify whether static or dynamic analysis is to be performed.</p><p>This choice is made from the Add Files file dialogue window, or from the popup menu.</p><p>OrcaFlex can auto-save partial completed dynamic simulations to file at regular intervals during the batch job. This</p><p>is useful if your computer is prone to failure (for example because of overnight power failures) since the part-run</p><p>simulation file can be loaded and continued, rather than having to re-run the whole simulation from scratch.</p><p>http://www.orcina.com/SoftwareProducts/OrcaFlex/Documentation/OrcFxAPIHelp</p><p>Automation, Batch Processing w</p><p>86</p><p>Multi-threading</p><p>The batch processing functionality can make use of multiple processor cores. So, for example, if you have a quad-</p><p>core machine then 4 simulation files can be run concurrently.</p><p>Since some batch tasks can depend on the output of other tasks OrcaFlex processes tasks in a very particular order,</p><p>as follows:</p><p> The batch script files are all processed first. Because it is common to write scripts that output data files it is</p><p>important to complete all batch scripts before processing the data files.</p><p> Any data or simulation files are processed next.</p><p> Fatigue files are processed next. These use simulation files as input and so should not be started until all data or</p><p>simulation files have been processed.</p><p> Finally any OrcaFlex spreadsheet files or load cases are processed. These also cannot be started until all data or</p><p>simulation files have been processed.</p><p>The commands in batch script files are processed sequentially. Consequently any simulations that are processed</p><p>with RunDynamics commands cannot be performed in parallel. Because of this it is advisable to use the SaveData</p><p>command rather than the RunDynamics command when creating batch scripts. Such a script would create a number</p><p>of OrcaFlex data files which you could then process in the batch form using all available processor cores.</p><p>Batch Form User Interface</p><p>Close</p><p>Dismisses the batch form.</p><p>Add Files</p><p>Adds jobs to the list. Files can also be added by drag and drop. That is if you are browsing your file system then you</p><p>can highlight files and drag them onto the jobs list.</p><p>Files can be added whilst a batch is running. Note that this feature has the limitation that all pre-existing jobs must</p><p>be run to completion before the program starts processing the files added whilst the batch was active.</p><p>Remove Files</p><p>Removes any files highlighted in the jobs list.</p><p>Check Files</p><p>OrcaFlex opens each file in the jobs list, checks that they contain valid OrcaFlex data or script commands and reports</p><p>any errors. When checking OrcaFlex spreadsheet or fatigue files it simply confirms the file exists.</p><p>Run Batch</p><p>Processes the list of jobs. If a job fails then it is abandoned but other jobs are still attempted. Any errors are reported</p><p>once all jobs have been processed.</p><p>Pause Batch</p><p>Pauses the currently running batch jobs. This can be useful if you temporarily want another process on your</p><p>machine to have the processor resource that OrcaFlex is using.</p><p>Stop Batch</p><p>Terminate processing of batch jobs.</p><p>Warnings</p><p>Displays a window allowing you to review all warnings generated by OrcaFlex during a calculation. These warnings</p><p>are suppressed when you are operating in batch mode and this button allows you to review them once the</p><p>simulation has completed.</p><p>Close program when Batch completes</p><p>If checked then OrcaFlex will close once the processing of jobs completes. This feature is intended principally for</p><p>users with networked licences. It allows you to release your claim on an OrcaFlex licence as soon as the batch of jobs</p><p>is complete.</p><p>w Automation, Batch Processing</p><p>87</p><p>4.2.2 Script Files</p><p>OrcaFlex provides special facilities for running a series of variations on a base data file, using a script file. This</p><p>contains a sequence of commands to read a data file, make modifications to it, and run the modified file, storing the</p><p>results for later processing. The file can also include comments. The syntax for the instructions is described in the</p><p>next topic.</p><p>Script files can be written using any text editor. However, it is quite unusual to do this because there are very</p><p>productive facilities in the OrcaFlex spreadsheet for automatically generating script files for regular sets of cases.</p><p>A more recently introduced alternative to script files are text data files. These can be used to specify load case</p><p>variations. Once again, the OrcaFlex spreadsheet offers a facility to generate these text data files.</p><p>4.2.3 Script Syntax</p><p>An OrcaFlex batch script is made up of commands, which are obeyed sequentially, and comments, which are</p><p>ignored. A comment is a line that is either blank or on which the first non-blank characters are "//". A command can</p><p>be:</p><p>1. A directive followed by one or more arguments, optionally separated by white space (one or more spaces or</p><p>tabs). For example: load c:\temp\test.dat where load is the directive and c:\temp\test.dat is the</p><p>argument.</p><p>2. An assignment of the form VariableName=value, again with optional white space separators. For example:</p><p>Length = 55.0.</p><p>Note that:</p><p> Directives, variable names, and model object names are all case independent.</p><p> If your script includes a relative file name then it is taken to be relative to the directory from which the script</p><p>was loaded.</p><p> File names, arguments, variables or values containing spaces or non-alphanumeric characters must be enclosed</p><p>in single or double quotes and they must not contain the same quote character as is used to enclose them. For</p><p>example '6" pipe' and "200' riser" are valid, but the following are not valid:</p><p>6 inch pipe – contains spaces, so needs to be enclosed in quotes;</p><p>6"pipe – contains a double quote, so needs to be enclosed in single quotes;</p><p>'6' pipe' – contains a single quote, so needs to be enclosed in double quotes instead of single.</p><p>4.2.4 Script Commands</p><p>The script commands are executed in the context of an active model. This can be either an OrcaFlex model</p><p>containing Vessels, Lines etc., or a Fatigue Analysis. The active model defaults, at the start of script execution to</p><p>being an OrcaFlex model. The active</p><p>Dongles labelled 'Hxxx' (where xxx is the dongle number) must be plugged into the machine on which OrcaFlex is</p><p>run. Dongles labelled 'Nxxx' can be used in the same way as 'Hxxx' dongles, but they can also be used over a</p><p>network, allowing the program to be shared by multiple users. In the latter case the dongle should be installed by</p><p>your network administrator; instructions can be found in the Dongle directory on the OrcaFlex installation disc.</p><p>Types of Dongle</p><p>Dongles are available for either parallel or USB ports, and these are functionally equivalent so far as OrcaFlex is</p><p>concerned. In general, USB dongles are preferred, since they seem to be more reliable. In any case, parallel ports are</p><p>becoming less common on new machines. By default, 'N' dongles can hold up to 10 OrcaFlex licences for use over a</p><p>network. We can supply dongles with larger capacities on request.</p><p>Dongle Troubleshooting</p><p>We supply, with OrcaFlex, a dongle utility program called OrcaDongle. If OrcaFlex cannot find the dongle then this</p><p>program may be used to check that the dongle is working correctly and has the expected number of licences. For</p><p>details see the OrcaDongle help file.</p><p>The OrcaDongle program is included on the OrcaFlex installation disc, and you may choose to install it from the</p><p>Autorun menu in the same way as OrcaFlex. It is also available for download from</p><p>www.orcina.com/Support/Dongle.</p><p>Also on our website, users of network dongles may find the Orcina Licence Monitor to be useful. This application</p><p>keeps track of the number of OrcaFlex licences claimed on a network at any time.</p><p>Diagnostics</p><p>If OrcaFlex fails to start, with the error that it can't obtain a licence, then please check the following.</p><p> If you are using a network dongle, are all the licences in use? The Orcina Licence Monitor may be of use in</p><p>determining this. If they are, you will need to wait until a licence becomes free before you can run OrcaFlex.</p><p>http://www.orcina.com/Support/Dongle</p><p>http://www.orcina.com/Support/OrcinaLicenceMonitor</p><p>w Introduction, Running OrcaFlex</p><p>13</p><p> If you are using a local dongle, is it plugged into your machine? If so, is the dongle device driver installed? You</p><p>can check this by running OrcaDongle. If the driver is not present, it may have been uninstalled by another</p><p>program: if so, you can fix this by Repairing the OrcaFlex installation (from the Windows Control Panel, select</p><p>'Add or Remove Programs' (XP) or Programs / Programs and Features (Vista), select the OrcaFlex entry, select</p><p>Change then Repair). If this still fails, you can install the driver by downloading from our website, and running,</p><p>the file Hasp-Setup.msi.</p><p> Does the dongle you are using have an OrcaFlex licence on it? Again, you can check this with OrcaDongle.</p><p> Do you have a licence file for the dongle you wish to access? This file will be named Nxxx.lic or Hxxx.lic (where</p><p>xxx is the dongle number) and will be in the OrcaFlex installation folder. If not, then you should be able to copy</p><p>the required file(s) from the root level of the OrcaFlex installation disc into the installation folder.</p><p>If none of these help, then please contact us at Orcina with a description of the problem. Ideally, please also email to</p><p>us the diagnostics file named OrcLog.txt which OrcaFlex will have written on failing to find a licence. This file can be</p><p>found in the folder "%appdata%/Orcina/OrcaFlex": to open this folder, select Start menu | Run… and enter the text</p><p>between the quotes (including the '%' characters).</p><p>1.2 RUNNING ORCAFLEX</p><p>A shortcut to run OrcaFlex is set up on the Start menu when you install OrcaFlex (see Start\Programs\Orcina</p><p>Software\).</p><p>This shortcut passes no parameters to OrcaFlex so it gives the default start-up behaviour; see below. If this is not</p><p>suitable you can configure the start-up behaviour using command-line parameters, for example by setting up your</p><p>own shortcuts with particular parameter settings.</p><p>Default Start-up</p><p>OrcaFlex has two basic modules: full OrcaFlex and statics-only OrcaFlex. A full OrcaFlex licence is needed for</p><p>dynamic analysis.</p><p>When you run OrcaFlex it looks for an Orcina dongle from which it can claim an OrcaFlex licence (either a full</p><p>licence or a statics-only licence). By default, it first looks for a licence on a local dongle (i.e. one in local mode and</p><p>connected to the local machine) and if none is found then it looks for a licence on a network dongle (i.e. one in</p><p>network mode and accessed via a licence manager over the network). This default behaviour can be changed by</p><p>command-line parameters.</p><p>If OrcaFlex finds a network dongle and there is a choice of which licences to claim from it, then OrcaFlex displays a</p><p>Choose Modules dialog to ask you which modules you want to claim. This helps you share the licences with other</p><p>users of that network dongle. For example if the network dongle contains both a full licence and a statics-only</p><p>licence then you can choose to use the statics-only licence, if that is all you need, so that the full licence is left free for</p><p>others to use when you do not need it yourself. The Choose Modules dialog can be suppressed using command-line</p><p>parameters.</p><p>Command Line Parameters</p><p>OrcaFlex can accept various parameters on the command line to modify the way it starts up. The syntax is:</p><p>OrcaFlex.exe Filename Option1 Option2 … etc.</p><p>Filename is optional. If present it should be the name of an OrcaFlex data file (.dat or .yml) or simulation file (.sim).</p><p>After starting up OrcaFlex will automatically open that file.</p><p>Option1, Option2 etc. are optional parameters that allow you configure the start-up behaviour. They can be any of</p><p>the following switches. For the first character of an option switch, the hyphen character '-' can be used as an</p><p>alternative to the '/' character.</p><p>Dongle Search switches</p><p>By default the program searches first for a licence on a local dongle and then for a licence on a network dongle. The</p><p>following switches allow you to modify this default behaviour.</p><p> /LocalDongle Only search for licences on a local dongle. No search will be made for network dongles.</p><p> /NetworkDongle Only search for licences on a network dongle. Any local dongle will be ignored. This can be</p><p>useful if you have a local dongle but want to use a network dongle that has licences for more modules.</p><p>http://www.orcina.com/Support/Dongle</p><p>Introduction, Parallel Processing w</p><p>14</p><p>Module Choice switch</p><p>This switch is only relevant if the dongle found is a network dongle and there is a choice of licences to claim from</p><p>that dongle. You can specify your choice using the following command line switch:</p><p> /DisableDynamics Choose the statics-only basic licence. This is sometimes useful when using a network dongle</p><p>since it allows you to leave full licences free for other users when you only need a statics-only licence.</p><p>If you do not specify all the choices then the program displays the Choose Modules dialog to ask for your remaining</p><p>choices. You can suppress this dialog using the following switch.</p><p> /DisableInteractiveStartup Do not display the Choose Modules dialog. The program behaves the same as if the</p><p>user clicks OK on that dialog without changing any module choices.</p><p>Batch Calculation switches</p><p>These switches allow you to instruct OrcaFlex to start a batch calculation as soon as the program has loaded. The</p><p>following switches are available:</p><p> /Batch Start a batch calculation as soon as the program has loaded. The batch calculation will contain all the</p><p>files specified on the command line (you can have more than one) in the order in which they are specified. You</p><p>can use relative paths which will be relative to the working directory.</p><p> /CloseAfterBatch Instructs the program to close once the batch is complete.</p><p> /BatchAnalysisStatics, /BatchAnalysisDynamics specify what type of analysis to perform to the specified files. If</p><p>these parameters are missing then the program defaults to dynamic analysis.</p><p> /FileList instructs the</p><p>model can change due to a Load/LoadData command, or following a</p><p>NewModel/NewFatigue command. Some of the commands have different interpretations, depending on what type</p><p>of model is active, as described below.</p><p>The following batch script commands are currently available. You need to put quotes round file names or other</p><p>parameters that include spaces or non-alphanumeric characters.</p><p>Load <FileName></p><p>Opens the OrcaFlex file named <FileName>. The file can be a data file, a simulation file or a fatigue analysis file.</p><p>LoadData <FileName></p><p>Opens the data from the OrcaFlex data file named <FileName>.</p><p>RunStatics <FileName></p><p>Perform statics for the current model and save the resulting simulation to <FileName>. After the file is saved the</p><p>model is reset.</p><p>RunDynamics <FileName></p><p>Run dynamics for the current model and save the resulting simulation to <FileName>. After the file is saved the</p><p>model is reset.</p><p>Automation, Batch Processing w</p><p>88</p><p>Note: We no longer recommend that you use the RunStatics and RunDynamics commands. The</p><p>commands in a batch script are executed sequentially. This means that if your machine has</p><p>multiple processors, those processors will not be fully utilised. The recommended approach is to use</p><p>the batch script to generate OrcaFlex data files and then add those to the batch job list. This will</p><p>result in the most effective use of processor resources.</p><p>Run <FileName> (OrcaFlex model active)</p><p>This command is identical to RunDynamics.</p><p>Run <FileName> (Fatigue active)</p><p>This command:</p><p>1. Performs the fatigue analysis.</p><p>2. Saves the results to <FileName> which should have the .ftg extension.</p><p>3. Saves tabular results to an Excel workbook with the same name, but an .xls extension.</p><p>Save <FileName> (OrcaFlex model active)</p><p>Save the current model to <FileName>. If calculation results (either statics or dynamics) are available then a</p><p>simulation file will be saved. Otherwise a data file will be saved. When saving data, if the file extension is .yml then a</p><p>text data file will be saved; otherwise a binary data file will be saved.</p><p>Save <FileName> (Fatigue active)</p><p>Saves the fatigue model to <FileName> which should have the .ftg extension.</p><p>SaveData <FileName></p><p>Save the data from the current model to <FileName>.</p><p>If the file extension is .yml then a text data file will be saved; otherwise a binary data file will be saved.</p><p>Note: In the Load/LoadData, Save/SaveData and RunStatics/RunDynamics/Run commands, if</p><p><FileName> is a relative path then it is taken to be relative to the directory from which the script</p><p>file was loaded.</p><p>ExtendSimulation <StageDuration></p><p>Adds a new stage of length <StageDuration>. This command is equivalent to the Calculation | Extend Dynamic</p><p>Simulation menu item. You would normally follow this command with a Run command.</p><p>Reset</p><p>Resets the current model. This command is equivalent to the Calculation | Reset menu item.</p><p>NewModel</p><p>This command makes the active model an OrcaFlex model, deletes all objects from the model and then resets data to</p><p>default values. This command is equivalent to the File | New menu item.</p><p>NewFatigue</p><p>This command makes the active model a Fatigue Analysis and then resets data to default values. This command is</p><p>equivalent to the Fatigue Analysis File | New menu item.</p><p>Create <ObjectType> [<ObjectName>]</p><p>Creates a new object of type <ObjectType>. The new object is automatically selected which means that subsequent</p><p>assignment commands apply to this new object.</p><p>The <ObjectType> parameter can be "Line Type", "Vessel Type", "Line", "Winch" etc. Select Edit | Add from the</p><p>Model Browser menu to see a list of possible values for this parameter.</p><p>Alternatively variable data sources can be created by setting the <ObjectType> parameter to "Bending Stiffness",</p><p>"Drag Coefficient" etc. This list of possible variable data source object types can be found in the Data Source Type</p><p>tree on the variable data form.</p><p>If the optional <ObjectName> parameter is included then the new object will be given that name.</p><p>w Automation, Batch Processing</p><p>89</p><p>Delete <ObjectName></p><p>Deletes the object called <ObjectName>.</p><p>Select [<Object Type>] <ObjectName></p><p>Specify the model object to which subsequent assignment commands will apply.</p><p>The <ObjectType> parameter is optional, and by default is 'object', meaning select the named model object.</p><p><ObjectName> must then be either the name of an object that exists in the current model or one of the reserved</p><p>names 'General' (for the General data form) or 'Environment' (for the Environment data form).</p><p>Some examples of the select and assignment commands are given in Examples of setting data.</p><p>Other <ObjectType> values only need to be specified in the following special cases.</p><p>If the Environment has been selected and there is more than one wave train, then before you can specify any wave</p><p>train data you must give another select command to select the wave train. This second select command has the</p><p>form:</p><p>Select WaveTrain <WaveTrainName></p><p>So, for example:</p><p>Select Environment</p><p>Select WaveTrain Primary</p><p>WaveDirection = 30.0</p><p>Similarly, if the Environment has been selected and there is more than one current data set, then you must select</p><p>one of them before specifying any current data. For example:</p><p>Select Environment</p><p>Select Current Current2</p><p>RefCurrentDirection = 270.0</p><p>Note that this is not the same as setting the Active Current. In fact, you should avoid setting up multiple current data</p><p>in batch scripts if possible: this is best done interactively on the Environment form.</p><p>If a vessel type has been selected and it has more than one draught, then before specifying any draught-dependent</p><p>data you must give another select command that selects the draught. This second select command has the form:</p><p>Select Draught <DraughtName></p><p>Before specifying data for RAOs you need to specify the type of RAOs – this can be either Displacement, WaveLoad</p><p>or QTF. This is done with a command of the form:</p><p>Select RAOs <RAO type></p><p>Similarly, before specifying vessel type data for a given wave direction you must give another select command to</p><p>select that direction. This takes the form:</p><p>Select Direction <Direction></p><p>So, for example:</p><p>Select "Vessel Type1"</p><p>Select Draught Transit</p><p>Select RAOs Displacement</p><p>RAOOriginX = 10</p><p>RAOOriginY = 0</p><p>RAOOriginZ = 2</p><p>Select Direction 45</p><p>RAOSurgeAmplitude[2] = 0.1</p><p>Select Direction 90</p><p>RAOSurgeAmplitude[2] = 0.16</p><p>When the a Fatigue Analysis is active, you need to select S-N and T-N curves before assigning their data. For</p><p>example:</p><p>Select SNcurve "S-N Curve1"</p><p>SNDataA = 23.0</p><p>Select TNcurve "T-N Curve1"</p><p>TNcurvem = 2.8</p><p>Note: Indentation with spaces or tabs is optional, but makes scripts more readable.</p><p>Automation, Batch Processing w</p><p>90</p><p>Assignment</p><p>Assignment commands take the form</p><p>VariableName = Value</p><p>The VariableName on the left hand side must be one of the recognised variable names and the named variable must</p><p>exist in the currently selected model object. The Value on the right hand side must be in the appropriate form for</p><p>that variable (i.e. numeric or text) and it must be given in the same units as used in the current model.</p><p>For example:</p><p>Select Vessel1</p><p>Length = 110</p><p>Draught = "Operating draught"</p><p>If VariableName is the name of a variable that appears in a check box in OrcaFlex then the Value should be Yes or No.</p><p>For example:</p><p>Select Environment</p><p>CurrentRamp = Yes</p><p>If VariableName is the name of a variable that appears in a table in OrcaFlex, then its row number must be given.</p><p>The row number is given as an index enclosed by either square or round brackets (don't mix them on the same line),</p><p>and is always 1-based, i.e. [1] is the first row of the table. Note that this sometimes requires care, since in OrcaFlex</p><p>the table might not be 1-based. For example, when setting the prescribed motion for a vessel, the command</p><p>PrescribedMotionVelocity[2] = 4.8</p><p>sets the velocity in the 2nd row of the table, but in this case the first row of the table is stage 0 (the build-up stage) so</p><p>this command (slightly confusingly) sets the velocity for stage 1.</p><p>More examples of the select and assignment commands are given in Examples of setting data.</p><p>InvokeWizard</p><p>Sets the data for the selected object using either the Line Type Wizard or the Plasticity Wizard. The selected object</p><p>must be either a line type or a bend stiffness variable data source. The input data for the Wizard should first be set</p><p>using data assignment commands.</p><p>An example of how to use this command is given in Examples of setting data.</p><p>InvokeLineSetupWizard</p><p>Invokes the Line Setup Wizard calculation. The input data for the Wizard should first be set using data assignment</p><p>commands.</p><p>An example of how to use this command is given in Examples of setting data.</p><p>WaveSearch <FileName></p><p>Exports the wave search spreadsheet to the specified file. The file can be an Excel spreadsheet (.xls), a tab delimited</p><p>file (.txt) or a comma separated file (.csv). The decision is taken based on the file extension that you specify. The</p><p>input data for the wave search should first be set using data assignment commands.</p><p>DisplacementRAOsReport <FileName> [<VesselName>]</p><p>SpectralResponseReport <FileName> [<VesselName>]</p><p>Exports the vessel response report spreadsheets to the specified file for the specified vessel. The file can be an Excel</p><p>spreadsheet (.xls), a tab delimited file (.txt) or a comma separated file (.csv). The decision is taken based on the file</p><p>extension that you specify. If no vessel is specified, and there is only one vessel in the model, then that vessel will be</p><p>used. The input data for the response reports should first be set using data assignment commands.</p><p>SHEAR7DataFile <LineName> <FileName></p><p>Exports to <FileName> a SHEAR7 data file for the line named <LineName>.</p><p>SHEAR7MdsFile <LineName> <FileName> [<FirstMode> <LastMode>]</p><p>Exports to <FileName> a SHEAR7 Mds file for the line named <LineName>.</p><p>The <FirstMode> and <LastMode> parameters are optional. If they are specified then mode numbers in the range</p><p><FirstMode> to <LastMode> inclusive are exported. If these parameters are omitted then all modes are exported.</p><p>w Automation, Batch Processing</p><p>91</p><p>Only the Transverse and Mostly Transverse modes are included in the exported file. If you have specified first and</p><p>last modes to export then these mode numbers refer to the transverse and mostly transverse modes. The program</p><p>takes the following steps:</p><p>1. Calculate all modes.</p><p>2. Sort the modes into order of decreasing period / increasing frequency.</p><p>3. Remove all modes which are not Transverse or Mostly Transverse.</p><p>4. Export the modes in the range <FirstMode> to <LastMode> inclusive.</p><p>SHEAR7OutputFile <LineName> <FileName></p><p>Exports to <FileName> the SHEAR7 output file for the line named <LineName>. The file extension that you specify</p><p>(e.g. .out, .plt etc.) is used to determine which output file is exported. This command is only available if the direct</p><p>SHEAR7 interface is in use.</p><p>4.2.5 Examples of setting data</p><p>The Select command is probably the most difficult script command to use. To help understand how it works we</p><p>present some examples of its use below:</p><p>Simple examples</p><p>For many objects the script commands for setting data take the form:</p><p>1. Select the object using the command Select <ObjectName>.</p><p>2. Set the data using one or more commands of the form VariableName = Value.</p><p>The object name is most easily found on the Model Browser. The variable name is found by opening the relevant</p><p>data form, selecting the required data item and pressing F7.</p><p>Some examples of this procedure follow:</p><p>Select Link1</p><p>UnstretchedLength = 50</p><p>Select "3D Buoy1"</p><p>Mass = 4</p><p>Volume = 8</p><p>Height = 7.5</p><p>Select Line1</p><p>IncludeTorsion = Yes</p><p>Note: The name "3D Buoy" needs to be enclosed in quotes because it contains a space. If the name</p><p>contains a double quote and spaces then it should be enclosed with single quotes.</p><p>Data in tables and indices</p><p>Some data in OrcaFlex appears in tables. For example consider the Structure page of the Line Data form which</p><p>specifies how a Line is made up of a number of sections. Each section is specified by its Line Type, length etc. The</p><p>following example sets the number of sections of the line to be 2 and then sets data for both sections in turn.</p><p>Select Line1</p><p>NumberOfSections = 2</p><p>LineType[1] = Riser</p><p>Length[1] = 75</p><p>TargetSegmentLength[1] = 4</p><p>LineType[2] = Rope</p><p>Length[2] = 200</p><p>TargetSegmentLength[2] = 20</p><p>Note that we use blank lines to lay out the script. This is not essential but makes reading the script easier.</p><p>Data which appears in tables is always set using the indexed notation used above. Having stated this rule, we</p><p>immediately break it in the section below!</p><p>Automation, Batch Processing w</p><p>92</p><p>Line Type, Clump Type and Flex Joint Type data</p><p>These data are set by first selecting the type by name and then assigning the data as illustrated below:</p><p>Select "Line Type1"</p><p>OuterDiameter = 0.28</p><p>InnerDiameter = 0.21</p><p>On the Line Types Data form there is an option to view the data for all Line Types at once or to view it by individual</p><p>Line Type. When the data is being viewed for all Line Types at once the data appears in tables with one row per Line</p><p>Type. However, the data must be set by first selecting the type by name and then assigning the data. You cannot set</p><p>Line Type using index notation.</p><p>Similar rules apply to Clump Type data and to Flex Joint Type data.</p><p>Drag Chain Type and Wing Type data</p><p>These data are also set by first selecting the type by name and then assigning the data. For example:</p><p>Select "Drag Chain Type1"</p><p>Length = 12</p><p>Select "Wing Type1"</p><p>NumberOfAngles = 12</p><p>Angle[2] = -80</p><p>Lift[2] = 0.2</p><p>Drag[2] = 0.15</p><p>Moment[2] = 0.5</p><p>Data found on the General Data form</p><p>Data found on the General Data form can be set as follows:</p><p>Select General</p><p>InnerTimeStep = 0.01</p><p>OuterTimeStep = 0.1</p><p>Data found on the Environment Data form</p><p>Data found on the Environment Data form can be set as follows:</p><p>Select Environment</p><p>SeaBedStiffness = 3000</p><p>SeaBedDamping = 80</p><p>For data specific to a particular wave train you must first select the Environment and then select the particular wave</p><p>train. This makes use of the alternative syntax for Select which is Select <Object Type> <ObjectName>. For a wave</p><p>train you replace <ObjectType> with WaveTrain and replace <ObjectName> with the name of the wave train as</p><p>defined on the Environment Data form. For example:</p><p>Select Environment</p><p>Select WaveTrain "Swell from SW"</p><p>WaveDirection = 135</p><p>WaveType = "Dean Stream"</p><p>WaveHeight = 2.5</p><p>WavePeriod = 18</p><p>Select WaveTrain "Local Wind Sea"</p><p>WaveDirection = 40</p><p>WaveType = JONSWAP</p><p>WaveHs = 5.7</p><p>WaveTz = 9</p><p>Data for Current data sets</p><p>Multiple Current data sets can be defined. Again this requires the alternative syntax for Select as shown below:</p><p>Select Environment</p><p>MultipleCurrentDataCanBeDefined = Yes</p><p>NumberOfCurrentDataSets = 2</p><p>CurrentName[1] = "120deg"</p><p>CurrentName[2] = "150deg"</p><p>Select Current "120deg"</p><p>RefCurrentDirection = 120</p><p>w Automation, Batch Processing</p><p>93</p><p>Select Current "150deg"</p><p>RefCurrentDirection = 150</p><p>ActiveCurrent = "150deg"</p><p>Vessel Type Data</p><p>Some Vessel Type data is set in a straightforward manner as follows:</p><p>Select "Vessel Type1"</p><p>Length = 120</p><p>PenWidth = 3</p><p>Symmetry = "XZ plane"</p><p>However, the majority of Vessel Type data requires that you also specify which draught the data applies to. For</p><p>example:</p><p>Select "Vessel Type1"</p><p>Select Draught "Transit Draught"</p><p>CurrentCoeffSurgeArea = 1200</p><p>CurrentCoeffSwayArea = 1100</p><p>CurrentCoeffYawAreaMoment = 120E3</p><p>To set data for displacement RAOs, wave load RAOs, wave</p><p>drift QTFs and sum frequency QTFs you must also specify</p><p>which type of RAO the data applies to. For example:</p><p>Select "Vessel Type1"</p><p>Select Draught "Survival Draught"</p><p>Select RAOs Displacement</p><p>RAOOriginX = 10</p><p>RAOOriginY = 0</p><p>RAOOriginZ = 2</p><p>Select RAOs WaveLoad</p><p>RAOOriginX = 0</p><p>RAOOriginY = 0</p><p>RAOOriginZ = 0</p><p>Select RAOs WaveDrift</p><p>RAOOriginX = -3</p><p>RAOOriginY = 0</p><p>RAOOriginZ = 4</p><p>Select RAOs SumFrequencyQTF</p><p>RAOOriginX = -3</p><p>RAOOriginY = 0</p><p>RAOOriginZ = 4</p><p>Note that the variable names are the same but different data is set depending on which type of RAOs has been</p><p>selected.</p><p>In addition, when setting RAO table data (for displacement RAOs, wave load RAOs and wave drift QTFs) you must</p><p>specify which direction the data applies to. For example:</p><p>Select "Vessel Type1"</p><p>Select Draught "Survival Draught"</p><p>Select RAOs Displacement</p><p>Select Direction 22.5</p><p>RAOYawAmplitude[2] = 0.13</p><p>Select Direction 45</p><p>RAOYawAmplitude[2] = 0.18</p><p>However, it is worth pointing out that situations where you would wish to specify RAO table data in a batch script</p><p>are rare. It is much more likely that you would import this data into OrcaFlex from some external source and then</p><p>save it as part of the base case data file.</p><p>P-y Model Data</p><p>P-y Model data is complicated because each depth needs to be selected before the model data can be accessed.</p><p>Select "P-y Model1"</p><p>NumberOfDepths = 3</p><p>Automation, Batch Processing w</p><p>94</p><p>DepthBelowSeabedFrom[1] = 0.0</p><p>DepthBelowSeabedFrom[2] = 10.0</p><p>DepthBelowSeabedFrom[3] = 20.0</p><p>SelectedDepthBelowSeabedFrom = 0.0</p><p>ModelType = "API RP 2A Soft Clay"</p><p>EffectiveUnitSoilDensity = 1.6</p><p>UndrainedShearStrength = 6.0</p><p>J = 0.5</p><p>Epsilonc = 4.0</p><p>SelectedDepthBelowSeabedFrom = 10.0</p><p>ModelType = "API RP 2A Sand"</p><p>EffectiveUnitSoilDensity = 1.3</p><p>C1 = 1.1</p><p>C2 = 2.0</p><p>C3 = 15.0</p><p>k = 42.0</p><p>SelectedDepthBelowSeabedFrom = 20.0</p><p>ModelType = "P-y Table"</p><p>NumberOfEntries = 2</p><p>Deflection[1] = 0.0</p><p>Resistance[1] = 0.0</p><p>Deflection[2] = 0.2</p><p>Resistance[2] = 11.0</p><p>SHEAR7 Data</p><p>SHEAR7 data ownership is divided between the General object and the Line object. The SHEAR7 file version, output</p><p>file options and S-N curve data is owned by the General object:</p><p>Select General</p><p>SHEAR7FileVersion = 4.6</p><p>SHEAR7OutputDmg = Yes</p><p>To access the S-N Curve table requires that the curve is selected first:</p><p>Select General</p><p>SelectedSHEAR7SNCurve = Curve2</p><p>SHEAR7SNCurveNumberOfPoints = 3</p><p>SHEAR7SNCurveS[3] = 10E5</p><p>SHEAR7SNCurveN[3] = 10E4</p><p>SHEAR7SNCurveEnduranceLimit = 750.7</p><p>SHEAR7 Whole Line Data and Stress Concentration Factors are accessed through the Line Data:</p><p>Select Line1</p><p>SHEAR7CurrentProfileDiscretisation = "Regular spacing"</p><p>SHEAR7CurrentProfileTargetSpacing = 10</p><p>SHEAR7LocalSCFArcLength[1] = 32.0</p><p>SHEAR7LocalSCF[1] = 1.15</p><p>The SHEAR7 Hydrodynamic and Structural Section Data applies to a line section, so the index of the section is</p><p>required:</p><p>Select Line1</p><p>SHEAR7StrouhalType[1] = "Rough Cylinder"</p><p>SHEAR7LiftFactor[1] = 0.9</p><p>SHEAR7SectionSNCurve[2] = Curve1</p><p>Variable Data sources</p><p>Data for Variable Data sources can be set from the batch script, although once again we feel it is unlikely that you</p><p>would need to do this often. The procedure for setting variable data sources is illustrated below:</p><p>Select Stiffness1</p><p>NumberOfRows = 3</p><p>IndependentValue[1] = 0</p><p>DependentValue[1] = 0</p><p>IndependentValue[2] = 0.2</p><p>DependentValue[2] = 1000</p><p>w Automation, Batch Processing</p><p>95</p><p>IndependentValue[3] = 0.4</p><p>DependentValue[3] = 5000</p><p>Note that IndependentValue and DependentValue are the variable names for the X and Y columns of the variable</p><p>data source. That is if you are setting data for a bending stiffness data source then IndependentValue denotes</p><p>curvature and DependentValue denotes bend moment.</p><p>Line Type Wizard</p><p>The Line Type Wizard can be used from batch script. First of all you must select the Line Type and set its Wizard</p><p>data. Once this is complete the Wizard is invoked using the InvokeWizard command as illustrated below:</p><p>Select "Line Type1"</p><p>WizardCalculation = "Homogeneous Pipe"</p><p>PipeMaterial = Steel</p><p>PipeOuterDiameter = 0.082</p><p>PipeWallThickness = 0.005</p><p>InvokeWizard</p><p>Select "Line Type2"</p><p>WizardCalculation = "Line with Floats"</p><p>FloatBaseLineType = "Line Type3"</p><p>FloatDiameter = 0.80</p><p>FloatLength = 1.2</p><p>FloatPitch = 5.5</p><p>InvokeWizard</p><p>Plasticity Wizard</p><p>The Plasticity Wizard can be used from batch script. First of all you must select the Bend Stiffness variable data</p><p>source and set its Wizard data. Once this is complete the Wizard is invoked using the InvokeWizard command as</p><p>illustrated below:</p><p>Select Stiffness1</p><p>StressOD = 0.30</p><p>StressID = 0.27</p><p>Type = "Ramberg-Osgood curve"</p><p>E = 230.0e6</p><p>RefStress = 385.0e3</p><p>InvokeWizard</p><p>Line Setup Wizard</p><p>The Line Setup Wizard can be used from batch script using the InvokeLineSetupWizard command. The input data</p><p>should be set before invoking. This data is owned by a variety of different objects. The model wide data (e.g.</p><p>calculation mode and convergence parameters) is owned by the General object. The line specific data is owned by</p><p>each individual line. The follow script illustrates this:</p><p>Select General</p><p>LineSetupCalculationMode = "Calculate Line Lengths"</p><p>LineSetupMaxDamping = 20</p><p>Select Line1</p><p>LineSetupTargetVariable = "End A Tension"</p><p>LineSetupTargetValue = 830.0</p><p>Select Line2</p><p>LineSetupIncluded = No</p><p>InvokeLineSetupWizard</p><p>Polar Coordinates data on the All Objects form</p><p>The All Objects data form allows end connection data to be specified as polar coordinates and this polar coordinates</p><p>data is only accessible from this form.</p><p>The data appears in a table containing all Line, Winch and Link connections. However, the data still belongs to each</p><p>individual object and the appearance of a table of data is purely presentational. This means that to set the data you</p><p>must first select the individual Line, Link or Winch and then set the data, as illustrated below:</p><p>Select Line1</p><p>PolarR[1] = 20.0</p><p>PolarTheta[1] = 45.0</p><p>PolarR[2] = 340.0</p><p>Automation, Batch Processing w</p><p>96</p><p>PolarTheta[2] = 45.0</p><p>Select Line2</p><p>PolarR[1] = 20.0</p><p>PolarTheta[1] = 90.0</p><p>PolarR[2] = 340.0</p><p>PolarTheta[2] = 90.0</p><p>Select Winch1</p><p>PolarR[3] = 0.0</p><p>PolarTheta[3] = 90.0</p><p>PolarR[4] = 10.0</p><p>PolarTheta[4] = 90.0</p><p>For lines and links an index of 1 means End A and an index of 2 means End B. For winches the index identifies the</p><p>winch connection point.</p><p>Colour data</p><p>Drawing colour data items can be set through batch script in a variety of ways. The simplest is to use the pre-defined</p><p>colours as follows:</p><p>Select "Line Type1"</p><p>PenColour = Red</p><p>Select "Line Type2"</p><p>PenColour = Green</p><p>The full list of pre-defined colours is: Black, Maroon, Green, Olive, Navy, Purple, Teal, Gray, Silver, Red, Lime, Yellow,</p><p>Blue, Fuchsia, Aqua, MoneyGreen, SkyBlue, Cream, MedGray and White.</p><p>If you want more control over the colour then you can specify an RGB value as an integer. The following example has</p><p>the same effect as the previous one:</p><p>Select "Line Type1"</p><p>PenColour = 255</p><p>Select "Line Type2"</p><p>PenColour = 65280</p><p>Using decimal values for RGB value is impractical. Instead a neat trick is to specify the colour as a hexadecimal value</p><p>by prefixing it with a $ sign as follows:</p><p>Select "Line Type1"</p><p>PenColour = $0000FF</p><p>Select "Line Type2"</p><p>PenColour = $00FF00</p><p>Select "Line Type3"</p><p>PenColour = $FF0000</p><p>This sets the colours to red, green and blue respectively. Each pair of hex digits controls the amount of red, green</p><p>and blue. So white is $FFFFFF and black is $000000. A value of $C0C0C0 gives a light grey and $808080 produces a</p><p>darker</p><p>grey.</p><p>Fatigue Analysis data</p><p>Fatigue analysis data is quite simple in the script. The only complication is that you must to select S-N and T-N</p><p>curves before assigning their data.</p><p>NewFatigue</p><p>DamageCalculation = "Homogeneous pipe stress"</p><p>AnalysisType = Rainflow</p><p>ArclengthIntervalsCount = 1</p><p>FromArclength[1] = 0.0</p><p>ToArclength[1] = 30.0</p><p>SCF[0] = 1.5</p><p>SNcurveCount = 2</p><p>SNcurveName[2] = ProjectSteel</p><p>Select SNcurve ProjectSteel</p><p>SNDataEnduranceLimit = 0.0</p><p>4.2.6 Handling Script Errors</p><p>As with other computer programs, OrcaFlex batch script files can easily contain errors. It is therefore wise to check</p><p>your script file for errors before running it as a batch job. To check for errors in your scripts, use the "Check Files"</p><p>w Automation, Batch Processing</p><p>97</p><p>button on the OrcaFlex batch form. This will read and obey all the commands in the script files except those that</p><p>perform calculations or write files. It will then report any errors it finds, including the line number on which the</p><p>error occurs. You can then correct the problem before running the script.</p><p>Warning: If you misspell a variable name in an assignment statement then "Check Files" will report an error.</p><p>But if you incorrectly specify a variable name which is nevertheless valid then OrcaFlex cannot</p><p>detect the error. So you need to be very careful that you use the correct variable names for the data</p><p>items that you want to change.</p><p>4.2.7 Obtaining Variable Names</p><p>Each OrcaFlex data item has its own name that is used to specify it in a script file. The names of the data items are</p><p>based on the corresponding labels used on the data form. To find out the name of a data item, open the appropriate</p><p>data form, select the data item, and then open (e.g. by right click) the pop-up menu and select the Batch Script</p><p>Names command (or press F7). This displays the variable name of the selected data item which you can select and</p><p>copy directly into your batch script.</p><p>If the data item is in a table (or group) of data items then the Batch Script Names form displays the names of all the</p><p>data items in the table. The different columns in the table each have their own names; you then need to add an index</p><p>to specify which row you want. The exceptions to this are the 'Connections' data controls for Lines and Links, which</p><p>consist of two rows, one for End A and one for End B. For these, the Batch Script Names form lists the names for End</p><p>A only: those for End B may be obtained by simply replacing 'EndA' with 'EndB' in the name.</p><p>Finally, note that Batch Script Names are not available for an empty table – e.g. if you want the names for the</p><p>attachments table on the line data form, but there are currently no attachments. In this case you must add a row to</p><p>the table before you can use the Batch Script Names form.</p><p>4.2.8 Automating Script Generation</p><p>The OrcaFlex Spreadsheet has facilities for automating the generation of a script file for a regular set of cases. To use</p><p>this facility select the Pre-processing worksheet, then select the Script Table cell and then click the Create Batch</p><p>Scripts command which can be found on the OrcaFlex menu in Excel.</p><p>The batch script filename is specified in the cell next to the Script Table cell. It is relative to the directory containing</p><p>this spreadsheet, so if you don't specify the folder name then it will be created in the folder containing this</p><p>spreadsheet.</p><p>Below the Script Table cell is a table defining the script, consisting of 3 sections:</p><p> First is one or more title rows (shown with a green background in the example below). Only the first table</p><p>column is used in these rows, and the contents of those cells are simply copied to the script. The other columns</p><p>are ignored. The title rows can therefore contain any comments or other script commands that you want to</p><p>appear at the start of the script. The title rows end at the first row with a blank cell in the table's first column.</p><p> Next is a series of header rows for the cases (shown with a blue background in the example below). The last</p><p>header row is deemed to be the next row with a comment command (i.e. starting with "//") in the first column.</p><p> Finally there are a series of rows, one row for each case. The cells in this section are processed from left to right</p><p>on each row, and then down to the next row, and each cell generates script commands as follows. If the cell is</p><p>empty then no script commands are generated. But if the cell is not empty then all the (non-empty) script</p><p>commands in the header rows in that column are written to the script, with the cell's value appended to the last</p><p>header row command. This allows different columns to set data values for the various cases, and a blank value</p><p>leaves the data item as it was in the previous case. The cases (and the whole table) end at the next row that has</p><p>a blank cell in the table's first column.</p><p> Note that you can add extra columns to the table or indeed remove columns from the table.</p><p> The table can be arranged with rows and columns transposed. To do this you must use the keyword Script</p><p>Table Row. An example of this alternative approach can be found in the default OrcaFlex spreadsheet template.</p><p>An example is shown below:</p><p>Automation, Batch Processing w</p><p>98</p><p>Figure: Example table for automatic batch script generation</p><p>The script generated by this table loads a base case from a file called "Base Case.dat". Because no path is specified</p><p>then this file is located in the same directory as the spreadsheet. Four cases are produced based on this data file with</p><p>current values of 0.5 and 0.8 and line lengths of 100 and 120.</p><p>Notes: The cell containing the base case data file name has the file name surrounded by quotes. This is</p><p>because the file name contains a space. However, the quotes are not needed for the file names in</p><p>the last column because they do not contain spaces.</p><p>The generated script adheres to the formatting specified in the Excel cells. So, if a cell is formatted</p><p>to have, say, 1 decimal place, the corresponding value in the script will also have 1 decimal place.</p><p>The script is generated as follows. First select the cell containing the text Script Table. Then drop down the</p><p>OrcaFlex menu contained in the main Excel menu and click Create Batch Scripts. When you do this you are</p><p>presented with the following window:</p><p>Figure: Automatically generated batch script</p><p>w Automation, Text Data Files</p><p>99</p><p>The script file has not been saved yet. You should check that the automatically generated script is as intended.</p><p>Should you wish to, you can modify the script file name at this point.</p><p>If there is a problem with the script you can click the Close button and correct the script table.</p><p>Save button</p><p>Saves the script file.</p><p>Save and Run button</p><p>Saves the script file and then processes it.</p><p>If the script has any Run commands then OrcaFlex is loaded and the script is processed by the standard OrcaFlex</p><p>batch form. Otherwise the script is processed from within Excel – progress is reported on the Excel status bar.</p><p>Save, Run and Submit button</p><p>Saves the script file and then processes it within Excel. Each data file saved by the script is then submitted to</p><p>Distributed OrcaFlex which runs and saves the simulation file.</p><p>Note: The Save, Run and Submit button is only available if Distributed OrcaFlex is installed on your</p><p>machine. In addition, it cannot be used if the script contains any Run commands.</p><p>Multiple tables</p><p>You can have multiple script tables within a workbook. To create all the batch scripts in one operation select all the</p><p>script tables and then click Create Batch Scripts in the OrcaFlex menu.</p><p>4.3 TEXT DATA FILES</p><p>4.3.1 Examples of setting data</p><p>This topic gives some examples of setting model data using the OrcaFlex Text Data file. The OrcaFlex Text Data file</p><p>format is described in the Text Data Files topic and this should be read before tackling this topic.</p><p>Building an entire OrcaFlex model</p><p>through the Text Data file is possible but not to be recommended. The normal</p><p>approach is to modify an existing model imported using the BaseFile identifier and apply incremental changes.</p><p>This results in a much more compact Text Data file that can be easily generated using a scripting language or by the</p><p>OrcaFlex spreadsheet. The OrcaFlex Text Data file format is not a scripting language so some Batch script command</p><p>operations are not possible – for example the InvokeWizard command.</p><p>The easiest way to see how data for a particular model item is represented is to create the item in OrcaFlex and then</p><p>save the data file as a Text Data file. Existing objects normally need to be selected by name before modifying their</p><p>data, although there are some exceptions that require specific selection identifiers and examples of these are given</p><p>below.</p><p>Setting simple data</p><p>To set data on an object existing in the base file 'BaseCase.yml', the object must be first selected by name, here</p><p>objects named 'Link1', '3D Buoy1' and 'Line1' are modified:</p><p>BaseFile: BaseCase.yml</p><p>Link1:</p><p>UnstretchedLength: 25</p><p>3D Buoy1:</p><p>Mass: 4</p><p>Volume: 8</p><p>Height: 7.5</p><p>Line1:</p><p>IncludeTorsion: Yes</p><p>Note: Object names and text data does not need to be enclosed in quotes, unless the text contains YAML</p><p>reserved characters (eg ': ', '- ', '# ' and ', '). So the name 'Line - Upper' needs</p><p>quoting but 'Line-Upper' does not.</p><p>Automation, Text Data Files w</p><p>100</p><p>Data in tables and indices</p><p>Table data is set using an index in square brackets [i] after the data name, where i is the index of the table row</p><p>starting at 1. The following example sets some data in the first two sections of Line1:</p><p>BaseFile: BaseCase.yml</p><p>Line1:</p><p>NumberOfSections: 2</p><p>LineType[1]: Riser</p><p>Length[1]: 75</p><p>TargetSegmentLength[1]: 4</p><p>LineType[2]: Rope</p><p>Length[2]: 200</p><p>TargetSegmentLength[2]: 20</p><p>The NumberOfSections identifier specifies the number of rows in the sections table, it is only required if we are</p><p>changing the size of the table. Every table has an associated row count data item, increasing the count will add new</p><p>rows to the end of the table containing default data, reducing the count will delete rows from the end of the table.</p><p>We could replace the table entirely and use a YAML list to repopulate the data, for example setting a new current</p><p>profile:</p><p>Environment:</p><p># Single Current</p><p>CurrentMethod: Interpolated</p><p>RefCurrentSpeed: 1.2</p><p>RefCurrentDirection: 36.0</p><p># Define the current profile table</p><p>CurrentDepth, CurrentFactor, CurrentRotation:</p><p>- [10, 1.0, 0]</p><p>- [50, 0.8, 0]</p><p>- [90, 0.5, 0]</p><p>Type data: Line, Clump, Flex Joint, Stiffener, Drag Chain and Wing</p><p>These objects also need to be referenced by name, they cannot be selected with index notation.</p><p>Line Type1:</p><p>OuterDiameter: 0.28</p><p>InnerDiameter: 0.21</p><p>Clump Type1:</p><p>Mass: 0.1</p><p>Volume: 0.2</p><p>Height: 4</p><p>DragAreaX: 0.7</p><p>Drag Chain Type1:</p><p>Length: 12</p><p>Wing Type1:</p><p>Angle[2]: -80</p><p>Lift[2]: 0.2</p><p>Drag[2]: 0.15</p><p>Moment[2]: 0.5</p><p>Creating new objects</p><p>New objects can be added to the model using the type name as the identifier, the object will be created with default</p><p>data that can be then modified. In the Text Data file the plural of the type name (eg LineTypes ) introduces a new</p><p>list of the type, and clears any existing objects from the list. To add a new line type to the line types list:</p><p>LineType:</p><p>Name: Variant Line Type3</p><p>OuterDiameter: 0.29</p><p>InnerDiameter: 0.20</p><p>w Automation, Text Data Files</p><p>101</p><p>Line1:</p><p>LineType[2]: Variant Line Type3</p><p>And some new attachment types:</p><p>ClumpType:</p><p>Name: Clump 5</p><p>DragArea: [0.7, 07, 0.1]</p><p>DragChainType:</p><p>Name: Short Chain 2</p><p>Length: 12</p><p>Note: Objects must created before they are referred to later in the file. So a new line type must be created</p><p>in the data file before a line can be later modified to refer to it.</p><p>Data found on the General And Environment Data forms</p><p>Data on these forms can be set by referencing the General or Environment objects as follows (the following example</p><p>assumes that the base file model has 2 simulation stages):</p><p>General:</p><p>ImplicitUseVariableTimeStep: Yes</p><p>ImplicitVariableMaxTimeStep: 0.2</p><p># Add another simulation stage</p><p>NumberOfStages: 3</p><p>StageDuration[3]: 12.0</p><p>Environment:</p><p>SeaBedStiffness: 3000</p><p>SeaBedDamping: 80</p><p>RefCurrentSpeed: 1.2</p><p>RefCurrentDirection: 36.0</p><p>Wave train data requires that the target wave train is selected by name first. The example assumes a base file model</p><p>with only one wave train and adds a new wave train and names it 'AiryWave' (after being added the wave train is</p><p>automatically selected). Then the first wave train is modified after being selected with the SelectedWave</p><p>identifier:</p><p>Environment:</p><p># Add a wave train</p><p>NumberOfWaveTrains: 2</p><p>WaveName[2]: AiryWave</p><p># AiryWave is now the selected wave</p><p>WaveType: Single Airy</p><p>WaveDirection: 180</p><p>WaveHeight: 3.2</p><p>WavePeriod: 12.5</p><p># Change selected wave to Wave1</p><p>SelectedWave: Wave1</p><p>WaveDirection: 100</p><p>WaveHeight: 4.3</p><p>WavePeriod: 7.8</p><p>Data for Multiple Current data sets</p><p>The example below creates two Currents in a multiple current set, and selects one to be the active current using the</p><p>ActiveCurrent identifier:</p><p>Environment:</p><p># Multiple current set</p><p>MultipleCurrentDataCanBeDefined: Yes</p><p>NumberOfCurrentDataSets: 2</p><p>CurrentName[1]: Ebb</p><p>CurrentName[2]: Flow</p><p># To modify the Ebb current, we must select it first</p><p>Automation, Text Data Files w</p><p>102</p><p>SelectedCurrent: Ebb</p><p>CurrentMethod: Power Law</p><p>CurrentSpeedAtSurface: 1.2</p><p>CurrentSpeedAtSeabed: 0.8</p><p>RefCurrentDirection: 180.0</p><p># Now select the other current</p><p>SelectedCurrent: Flow</p><p>CurrentMethod: Power Law</p><p>CurrentSpeedAtSurface: 1.2</p><p>CurrentSpeedAtSeabed: 0.8</p><p>RefCurrentDirection: 0.0</p><p># Set the active current</p><p>ActiveCurrent: Ebb</p><p>Vessel Type data</p><p>Simple vessel type data is set as for other type data mentioned above, by referencing the vessel type by name first:</p><p>Vessel Type1:</p><p>Length: 120</p><p>PenWidth: 3</p><p>Symmetry: XZ plane</p><p>Much vessel data applies to a draught which must also then be referenced by name:</p><p>Vessel Type1:</p><p>Draught1:</p><p>Mass: 7600</p><p>CentreOfGravity: [2.53, 0, -1.97]</p><p>To set data for displacement RAOs, wave load RAOs and wave drift QTFs you must also specify which type of RAO</p><p>the data applies to:</p><p>Vessel Type1:</p><p>Draught1:</p><p>DisplacementRAOs:</p><p>RAOOrigin: [2.53, 0, -1.97]</p><p>LoadRAOs:</p><p>RAOOriginY: -1.2</p><p>The RAO data is per direction, so the direction also needs to be selected using the</p><p>SelectedRAODirectionValue YAML identifier. This example sets the Yaw amplitude in the second row in the</p><p>Period table for directions 22.5 and 45 degree of the Wave drift RAOs:</p><p>BaseFile: BaseCase.yml</p><p>Vessel Type1:</p><p>Draught1:</p><p>WaveDrift:</p><p>SelectedRAODirectionValue: 22.5</p><p>RAOYawAmp[2]: 0.13</p><p>SelectedRAODirectionValue: 45</p><p>RAOYawAmp[2]: 0.18</p><p>To modify data in the frequency dependent added mass and damping matrices, the frequency or period needs to be</p><p>selected first, using the SelectedAddedMassAndDampingPeriodOrFrequency identifier, to access the</p><p>relevant tables. Data in the tables is accessed using index notation:</p><p>Vessel Type1:</p><p>Draught1:</p><p>SelectedAddedMassAndDampingPeriodOrFrequency: 5.5</p><p>AddedMassMatrixX[1]: 255</p><p>AddedMassMatrixY[2]: 249</p><p>AddedMassMatrixZ[1]: 136</p><p>DampingY[2]: 0.4</p><p>It is unlikely that you will want to change individual values in the RAO tables, however the Vessel, Draught and RAO</p><p>sections of the Text Data File are ideal candidates for using the IncludeFile identifier:</p><p>w Automation, Text Data Files</p><p>103</p><p>Vessel Type1:</p><p>Draught1:</p><p>DisplacementRAOs:</p><p>IncludeFile: RAOs\UnladenRAOs.yml</p><p>P-y Model Data</p><p>With P-y Model data, each depth needs to be selected before the model data can be accessed:</p><p># Create a new P-y model</p><p>P-yModel:</p><p>Name: P-yModel1</p><p>NumberOfDepths: 3</p><p>DepthBelowSeabedFrom[1]: 0.0</p><p>DepthBelowSeabedFrom[2]: 10.0</p><p>DepthBelowSeabedFrom[3]: 20.0</p><p># Modify existing P-y model</p><p>P-yModel1:</p><p>SelectedDepthBelowSeabedFrom:</p><p>0</p><p>ModelType: API RP 2A Soft Clay</p><p>EffectiveUnitSoilDensity: 1.6</p><p>UndrainedShearStrength: 6</p><p>J: 0.5</p><p>Epsilonc: 4</p><p>SelectedDepthBelowSeabedFrom: 10</p><p>ModelType: API RP 2A Sand</p><p>EffectiveUnitSoilDensity: 0</p><p>C1: 0</p><p>C2: 2</p><p>C3: 15</p><p>k: 42</p><p>SelectedDepthBelowSeabedFrom: 20</p><p>ModelType: P-y Table</p><p>Deflection, Resistance:</p><p>- [0, 0]</p><p>- [0.2, 11]</p><p>Note: The above example creates a new P-y Table with two rows. To modify rows in an existing table, use</p><p>indexing, eg: Deflection[2]: 0.2.</p><p>SHEAR7 Data</p><p>SHEAR7 Data ownership is divided between Line objects and the General object. The SHEAR7 file version, output</p><p>file options and S-N curve data is owned by the General object:</p><p>General:</p><p>SHEAR7FileVersion: 4.6</p><p>SHEAR7OutputDmg: Yes</p><p>To access the data in the S-N Curve table requires that the curve is first selected with the</p><p>SelectedSHEAR7SNCurve identifier:</p><p>General:</p><p>SelectedSHEAR7SNCurve: Curve2</p><p>SHEAR7SNCurveNumberOfPoints: 3</p><p>SHEAR7SNCurveS[3]: 10E5</p><p>SHEAR7SNCurveN[3]: 10E4</p><p>SHEAR7SNCurveEnduranceLimit: 750.7</p><p>SHEAR7 Whole Line Data and Stress Concentration Factors are accessed through a line object:</p><p>Line1:</p><p>SHEAR7CurrentProfileDiscretisation: Regular spacing</p><p>SHEAR7CurrentProfileTargetSpacing: 10</p><p>Automation, Text Data Files w</p><p>104</p><p>SHEAR7LocalSCFArclength[1]: 32.0</p><p>SHEAR7LocalSCF[1]: 1.15</p><p>The SHEAR7 Hydrodynamic and Structural Section Data applies to a line section, so the index of the section is</p><p>required:</p><p>Line1:</p><p>SHEAR7StrouhalType[1]: Rough Cylinder</p><p>SHEAR7LiftFactor[1]: 0.9</p><p>SHEAR7SectionSNCurve[2]: Curve1</p><p>Line Contact Data</p><p>To edit Penetrator data on the Line Contact data form the Penetrator locations set needs to be selected first using</p><p>the SelectedPenetratorLocationsDataSet identifier:</p><p>LineContactData:</p><p>SelectedPenetratorLocationsDataSet: Locations1</p><p>Penetratorx[2]: 13.6</p><p>Penetratory[2]: -2.5</p><p>PenetratorContactArea[2]: 0.85</p><p>Variable Data sources</p><p>New variable data sources can be created in two ways, the first example creates a new Fluid Temperature data item</p><p>with 2 table rows:</p><p>VariableData:</p><p>FluidTemperature:</p><p>- Name: fluidtempA</p><p>IndependentValue, DependentValue:</p><p>- [10, 17]</p><p>- [100, 11]</p><p>The above YAML also clears the Fluid Temperature data source list before adding 'fluidTempA'. If any existing</p><p>variable data items are referenced by other model objects then an error will be raised. If you wish to add another</p><p>variable data item and retain existing data items in the list then use the following YAML format:</p><p>VariableData:</p><p>FluidTemperature:</p><p>Name: fluidTempB</p><p>IndependentValue, DependentValue:</p><p>- [10, 15]</p><p>- [100, 9.5]</p><p>Existing variable data sources can be referenced by name as with other model objects. The following example resets</p><p>the table values for a Bending Stiffness variable data item:</p><p>BaseFile: BaseCase.yml</p><p>Stiffness1:</p><p>IndependentValue, DependentValue:</p><p>- [0, 0]</p><p>- [0.2, 1000]</p><p>- [0.4, 5000]</p><p>Polar Coordinates data on the All Objects form</p><p>End connection data can be expressed using polar coordinates as presented on the All objects data form. Although</p><p>this data is displayed in table form, it is still accessed by referencing the relevant object:</p><p>Line1:</p><p>PolarR[1]: 20.0</p><p>PolarTheta[1]: 45.0</p><p>PolarR[2]: 20.0</p><p>PolarTheta[2]: 345.0</p><p>Line2:</p><p>PolarR[1]: 20.0</p><p>PolarTheta[1]: 90.0</p><p>w Automation, Text Data Files</p><p>105</p><p>PolarR[2]: 3400.0</p><p>PolarTheta[2]: 90.0</p><p>Winch1:</p><p>PolarR[3]: 0.0</p><p>PolarTheta[3]: 90.0</p><p>PolarR[4]: 10.0</p><p>PolarTheta[4]: 90.0</p><p>For lines and links, End A has an index of 1 and End B an index of 2. For winches the index identifies the winch</p><p>connection point.</p><p>Colour data</p><p>Colour data can be set using pre-defined colours or RGB values as described for Batch scripts:</p><p>Line Type1:</p><p>PenColour: Red</p><p>Line Type1:</p><p>PenColour: 255</p><p>Line Type1:</p><p>PenColour: $00FF00</p><p>Importing Text Data File sections</p><p>Sections of an OrcaFlex Text Data file can be imported using the IncludeFile directive. This specifies another</p><p>YAML file containing a section of an OrcaFlex Text Data file that will be processed as if the data were part of the</p><p>original file. The imported segment cannot refer to objects that do not yet exist in the main data file. Using</p><p>IncludeFile is a useful way of adding or modifying complex data from a library of common object data, for</p><p>example Vessel ROAs:</p><p>Vessel Type1:</p><p>Draught1:</p><p>DisplacementRAOs:</p><p>IncludeFile: MyVesselRAOs.yml</p><p>The data in the included file must continue from where the original file left off but there is no need to repeat the</p><p>YAML header, or start at the same indentation level, although relative indentation in the include file is still required:</p><p># File: C:\Desktop\MyVesselRAOs.yml</p><p>RAOOrigin: [2.53, 0, -1.97]</p><p>PhaseOrigin: [~, ~, ~]</p><p>RAOs:</p><p>- RAODirection: 0</p><p>RAOPeriodOrFreq, RAOSurgeAmp, RAOSurgePhase, RAOSwayAmp, RAOSwayPhase,</p><p>RAOHeaveAmp, RAOHeavePhase, RAORollAmp, RAORollPhase, RAOPitchAmp,</p><p>RAOPitchPhase, RAOYawAmp, RAOYawPhase:</p><p>- [0, 0, 360, 0, 0, 0, 360, 0, 0, 0, 0, 0, 0]</p><p># etc..</p><p>The IncludeFile identifier can be used more than once in the same OrcaFlex Text Data file and the included files</p><p>can also contain the IncludeFile identifier themselves. A very simple OrcaFlex Text Data file my comprise just</p><p>the following:</p><p>%YAML 1.1</p><p>---</p><p># This File: C:\Desktop\Case x.yml</p><p>BaseFile: BaseCase y.yml</p><p>IncludeFile: Variation set z.yml</p><p>...</p><p>The above file is easy to create using a script, substituting file names for the BaseFile and IncludeFile files</p><p>from a collection of initial cases and variation sets.</p><p>Automation, Text Data Files w</p><p>106</p><p>4.3.2 Automating Generation</p><p>The OrcaFlex Spreadsheet has facilities for automating the generation of text data files for a regular set of cases. To</p><p>use this facility select the Pre-processing worksheet, then select the Text Data Files cell and then click the Create</p><p>Text Data Files command which can be found on the OrcaFlex menu in Excel.</p><p>The basic idea is very similar to the facility for automating generation of batch script files. An example table is</p><p>shown below:</p><p>Figure: Example table for automatic text data file generation</p><p>The cell containing "Text Data Files", highlighted in yellow, is known as the anchor cell. The text data files are</p><p>generated based on the template file specified the in cell immediately to the right of the anchor cell. In this example</p><p>the template file might look like this:</p><p>BaseFile: Base Case.dat</p><p>Environment:</p><p>WaveDirection: %direction</p><p>WaveHeight: %height</p><p>Line1:</p><p>Length[1]: %length</p><p>The row immediately below the anchor cell, highlighted in blue, contains variable names. You are free to choose</p><p>these names as you please. We have adopted a convention that the variable names begin with a percentage sign (%).</p><p>Although you do not need to follow this convention, doing so will have the benefit of making the variable names</p><p>stand out.</p><p>The rows beneath the variable names row are known as the value rows. Each row defines a single text data file. The</p><p>text data file is generated by starting from the template file and then replacing each variable name, in turn, by the</p><p>value specified in the table. The %filename variable name is compulsory, that is it must be included as one of the</p><p>variable names. It specifies the name of the generated text data file. Relative paths can be used for the template file</p><p>name and the output file names.</p><p>The extent of the table is determined by the presence of empty cells. So the variable names row ends at the first</p><p>empty cell. Likewise the value rows end at the first empty cell in the column beneath the anchor cell.</p><p>The example above produces 8 text data files as its output, named Case01.yml, Case02.yml, etc. This first of these</p><p>looks like this:</p><p>BaseFile: Base Case.dat</p><p>Environment:</p><p>WaveDirection: 0</p><p>WaveHeight: 8</p><p>Line1:</p><p>Length[1]: 100</p><p>Note: The generated text data files adhere to the formatting specified in the Excel cells. So, if a cell is</p><p>formatted to have, say, 1 decimal</p><p>place, the corresponding value in the text data file will also have</p><p>1 decimal place.</p><p>Choosing variable names</p><p>It is clearly important that you choose unique variable names. However, there is a further subtlety which can arise</p><p>when one variable name is a sub-string of another. For example, consider the variable names %x1 and %x10. When</p><p>w Automation, Post-processing</p><p>107</p><p>occurrences of %x1 in the template file are replaced by their actual values, the first 3 characters of any occurrences</p><p>of %x10 will also be detected.</p><p>Such ambiguities seldom arise, but if you are affected then you can extend the naming convention to include a</p><p>trailing % sign. In the example given above, the variable names become %x1% and %x10% and clearly the problem</p><p>does not arise.</p><p>Multiple tables</p><p>You can have multiple tables within a workbook. To process all the tables in one operation, select all the tables and</p><p>then click the Create Text Data Files command.</p><p>Benefits over script tables</p><p>The text data file approach to load case file generation described above is very similar to the approach using batch</p><p>script files. The choice of which to use is largely one of personal preference. If you are already familiar with batch</p><p>script and not yet familiar with text data files then it may prove easier to continue using batch script.</p><p>There is one significant advantage of using text data files which is that it avoids duplication of the OrcaFlex model</p><p>data. Consider the following typical sequence of actions when using batch script where we assume that the basic</p><p>model and scripts are already in place:</p><p>1. Modify the single base model, represented by an OrcaFlex data file.</p><p>2. Run the batch script (or scripts) that generate all the load case data files.</p><p>3. Run the simulations for all load case data files.</p><p>If text data files are used, as described above, then step 2 is not required. This is because the load case text data files</p><p>contain a reference to the base model rather than containing a copy as is the case when using batch script.</p><p>This is a relatively minor advantage but it does reduce the likelihood of mistakenly forgetting to carry out step 2</p><p>when using batch script files. In addition, more complex analyses can lead to your load cases being defined by</p><p>multiple script files which have to be executed in a particular order. Using the text data file approach means that this</p><p>complexity is dealt with just once when setting up the text data files, as opposed to every time a modification to the</p><p>base model is made.</p><p>4.4 POST-PROCESSING</p><p>4.4.1 Introduction</p><p>OrcaFlex users often use spreadsheets to post-process their OrcaFlex results. This can be done manually by</p><p>transferring the results from OrcaFlex into the spreadsheet using copy + paste. However, this is laborious and error</p><p>prone if a lot of results need transferring, so we have developed special facilities to automate the process.</p><p>This automation is done using an Excel spreadsheet that has facilities for automatic extraction of specified results</p><p>from one or more OrcaFlex files into nominated cells in the spreadsheet. You can then use the normal spreadsheet</p><p>facilities to calculate other post-processed results from those OrcaFlex results.</p><p>Note: The OrcaFlex spreadsheet works with Excel 2000 or later and requires OrcaFlex to be installed on</p><p>the machine.</p><p>Creating OrcaFlex Spreadsheets</p><p>You can create OrcaFlex spreadsheets from an Excel template that is supplied with OrcaFlex. You should base your</p><p>own OrcaFlex spreadsheets on this template, which is installed in the OrcaFlex installation directory when you</p><p>install OrcaFlex on your machine. To create your own OrcaFlex spreadsheet, open the Windows Start menu, select</p><p>Programs | Orcina Software and then select New OrcaFlex Spreadsheet. This shortcut creates a new spreadsheet</p><p>based on the template.</p><p>Before you try to use the new spreadsheet you need to save it to a file; it can be given any valid file name. It is</p><p>usually most convenient to save it to the directory containing the OrcaFlex files from which you want to extract</p><p>results. You can then specify the names of those files in the spreadsheet using relative paths. Using relative paths</p><p>makes it easier to rename the directory or move the spreadsheet and OrcaFlex files to some other directory.</p><p>4.4.2 OrcaFlex Spreadsheet</p><p>The OrcaFlex Spreadsheet enables you to automate the extraction of results and data from OrcaFlex files into Excel.</p><p>OrcaFlex spreadsheets also provide facilities for automating the production of batch script files and text data files.</p><p>Automation, Post-processing w</p><p>108</p><p>For results post-processing, an OrcaFlex Spreadsheet contains one or more instructions worksheets, plus other</p><p>worksheets to receive the OrcaFlex results and for any derived results. The spreadsheet also provides tools to help</p><p>build the list of instructions. These tools are the Instructions Wizard and the Duplicate Instructions form.</p><p>Instructions Table</p><p>Figure: Empty instructions table</p><p>Each row in the instructions table is a separate instruction. The instruction can be thought of as 3 separate sections:</p><p>1. The entry in column A (titled Sheet Name) specifies the name of the Excel worksheet on which any output is</p><p>produced.</p><p>2. The entries in columns B and C (titled Label Cell and Label respectively) specify a label. This label is output on</p><p>the worksheet specified in column A and in the cell specified in column B. The text of the label is specified in</p><p>column C.</p><p>3. The other columns (D to I) specify some results or data which are output on the sheet specified in column A and</p><p>in the cell specified in column D. These columns can specify output of time histories, range graphs, data values</p><p>etc.</p><p>Either of sections 2 and 3 are optional. That is you can have an instruction that has a blank command cell and so</p><p>only writes a label, or one that has a blank label cell and so only writes results.</p><p>The end of the table is indicated by the first row that has blank label cell, label and command columns. Hence you</p><p>cannot have an instruction row that has no label and no command. In particular, you cannot have a blank row in the</p><p>middle of the instruction table. Also, the spreadsheet assumes that the first instruction is row 5 of the worksheet, so</p><p>do not insert or delete rows above this.</p><p>Any formatting is ignored and so you can use bold, italic, colour etc. to make the worksheets easy to read. Likewise,</p><p>hidden rows in the instructions table are ignored allowing you to disable certain instructions which can useful when</p><p>developing and building the table.</p><p>Warning: Do not change rows 3 and 4 of an instructions table, since these are used to identify it as such.</p><p>Processing the Instructions</p><p>When you are working with the OrcaFlex Spreadsheet an OrcaFlex menu is added to the Excel menu bar. This menu</p><p>contains various commands to process the results instructions.</p><p>w Automation, Post-processing</p><p>109</p><p>Figure: The OrcaFlex menu within Excel</p><p>Excel 2007 and later replace the menus with Microsoft's ribbon interface. The OrcaFlex Spreadsheet integrates with</p><p>the ribbon as shown below:</p><p>Figure: The OrcaFlex ribbon within Excel 2007 and later</p><p>Throughout the documentation we refer to menu items, but if you are using a ribbon based version of Excel then you</p><p>should interpret this as referring to the corresponding ribbon button.</p><p>The Process All Instructions menu item runs all the instructions in the table. If the currently selected sheet is not</p><p>an instructions sheet and the workbook contains more than one instructions sheet, then you will be asked to select</p><p>which instructions sheet you wish to process. The Process Selected Instructions menu item tells the spreadsheet</p><p>to process only the instructions in the currently selected cell or block of cells.</p><p>Spreadsheet Processing Options</p><p>The Processing Options menu item allows you to change the way an instructions sheet is processed.</p><p>If an instruction depends upon the result of</p><p>a previous instruction, i.e. one of the cells in the row is a reference to the</p><p>output of an earlier instruction, then the Contains Dependencies box must be checked to ensure that the whole</p><p>sheet is processed line by line from top to bottom using a single thread. If this box is not checked, then the order in</p><p>which instructions are processed is not defined and multiple lines may be processed simultaneously by multiple</p><p>threads. If this box is checked, then you have the option to allow errors to be reported during the processing or</p><p>Ignore Errors until the sheet is completed, which ensures an unattended spreadsheet will continue to process</p><p>remaining instructions even if an error occurs. If Ignore Errors is checked then all error messages are collated and</p><p>reported on completion.</p><p>The Thread Count can be set to reduce the impact processing spreadsheets will have on the responsiveness of your</p><p>computer. By default the spreadsheet will utilise all the available processing cores. It is only available if Contains</p><p>Dependencies is not checked.</p><p>Automation, Post-processing w</p><p>110</p><p>Note: When a spreadsheet is processed in an OrcaFlex Batch all the option settings are ignored apart</p><p>from "Contains Dependencies". Errors are always ignored until processing completes and the</p><p>number of threads used is controlled by OrcaFlex.</p><p>Automating post-processing from VBA</p><p>Sometimes it is convenient to be able to invoke the post-processing actions from VBA. You can do so like this:</p><p>Dim module as Object</p><p>Set module = Application.COMAddIns.Item("PostProcessing.OrcaFlexSpreadSheet").Object</p><p>module.ProcessAll</p><p>This is equivalent to pressing the Process All button. To invoke the Process Selected button programmatically you</p><p>use the ProcessSelected method:</p><p>module.ProcessSelected</p><p>Finally, the processing options are can also be controlled by means of the following properties:</p><p>module.ContainsDependencies = True</p><p>module.IgnoreErrors = False</p><p>module.ThreadCount = 4</p><p>Re-enabling the spreadsheet add-in</p><p>The OrcaFlex spreadsheet is implemented as an Excel add-in. Sometimes, for example after an Excel crash, the add-</p><p>in can become disabled and needs to be re-enabled. The method for achieving this differs depending on the version</p><p>of Excel.</p><p>Excel 2003</p><p>1. On the Excel Help menu, click About Microsoft Office Excel.</p><p>2. Click Disabled Items which brings up the Disabled Items dialog.</p><p>3. Select the OrcaFlex spreadsheet in the Disabled Items dialog and click Enable.</p><p>4. Restart Excel.</p><p>5. In some cases, a reboot is also required for the change to take effect.</p><p>Excel 2007/2010</p><p>1. Open the Excel Options dialog.</p><p>2. Select the Add-ins page.</p><p>3. Select Disabled Items in the Manage drop-down list.</p><p>4. Click the Go button which brings up the Disabled Items dialog.</p><p>5. Select the OrcaFlex spreadsheet and click Enable.</p><p>6. Restart Excel.</p><p>7. In some cases, a reboot is also required for the change to take effect.</p><p>The above instructions refer to what Microsoft term hard disabling. If the above actions do not resolve the problem,</p><p>then it is possible that the add-in has been soft disabled instead – the instructions for re-enabling are as follow:</p><p>Excel 2007/2010</p><p>1. Open the Excel Options dialog.</p><p>2. Select the Add-ins page.</p><p>3. Select COM Add-ins in the Manage drop-down list.</p><p>4. Click the Go button which brings up the COM Add-ins dialog.</p><p>5. Check the box next to the OrcaFlex spreadsheet and click OK.</p><p>6. Restart Excel.</p><p>w Automation, Post-processing</p><p>111</p><p>4.4.3 Instruction Format</p><p>The easiest way to learn about the instruction format is by using the Instructions Wizard which allows you to create</p><p>instructions in an interactive manner.</p><p>In the OrcaFlex Spreadsheet, each instruction consists of the following cells.</p><p>Sheet Name</p><p>Specifies the name of the worksheet in which cells are to be written. If a worksheet with this name already exists</p><p>then the specified label and output cells will be overwritten, but other cells will be left unchanged. If no sheet of</p><p>that name exists then one will be created.</p><p>Label Cell</p><p>Specifies the cell, in the specified worksheet, to which the label (if not empty) will be written.</p><p>Label</p><p>Specifies the label string to be written to the label cell. This cell can be left empty, in which case the label cell is</p><p>ignored.</p><p>Output Cell</p><p>Specifies the cell, in the specified worksheet, to which results or data should be written. Some commands specify</p><p>multiple-value output – for example a time history consists of a column of results. In this case the output cell</p><p>specifies the top left cell of the block of cells to be written.</p><p>Note: The output cell (or label cell) can be specified directly, e.g. B7, but can also be specified indirectly</p><p>using standard Excel formulae.</p><p>Command</p><p>This should be one of the pre-defined commands or else empty. If the command cell is empty then the output cell is</p><p>ignored and just the label is output.</p><p>Object Name</p><p>The name of the OrcaFlex object whose results or data are output.</p><p>Note: This name is case sensitive. Different objects in OrcaFlex can have identical names except for case.</p><p>For example "LINE" and "line" and "LiNe" are all regarded as different objects in OrcaFlex.</p><p>Additional Data</p><p>This column is used when outputting results for certain types of OrcaFlex object.</p><p>For the Environment object you need to specify the global X,Y,Z coordinates of the point for which you want results</p><p>– the coordinates must be separated by the ';' character. If no point is specified then (0,0,0) will be assumed.</p><p>For Vessel objects some results require the local x,y,z coordinates of the point for which you want results – the</p><p>coordinates must be separated by the ';' character or leave blank to use the vessel origin.</p><p>For 6D Buoy objects you must specify the Wing Name if you are requesting a wing results variable or a point in local</p><p>x,y,z buoy coordinates for some results variables – the coordinates must be separated by the ';' character or leave</p><p>blank to use the buoy origin.</p><p>For Winch objects you may need to specify the winch connection number.</p><p>For Line objects you must specify the position on the line for which results are wanted. There are a variety of ways</p><p>in which this can be specified:</p><p> The position can be specified by arc length, e.g. "Arclength 25.0".</p><p> The node number can be specified, e.g. "Node 4".</p><p> One of the line ends can be specified, e.g. "End A", "End B" or more concisely "A" or "B".</p><p> The touchdown position can be specified, e.g. "Touchdown".</p><p> For stress results you must also specify the position of the point within the cross section through the specified</p><p>arc length. You do this by specifying R,Theta values, e.g. "Inner", "Outer", "Theta 270.0".</p><p>Automation, Post-processing w</p><p>112</p><p>Note: You must specify an arc length together with both R and Theta separated by the ';' character, e.g.</p><p>"Arclength 20.0; Inner; Theta 270.0", "End A; Outer; Theta -45.0"; "Node 7; Outer; Theta 17.8" etc.</p><p> Clearance results can be reported either as clearances from this line to all other lines or from this line to a</p><p>specified other line. You can specify this other line by adding its name after the position, e.g. "Arclength 35;</p><p>Line2", "Node 4; Riser"; "End B; Hose" etc. If you do not specify another line (e.g. "Arclength 35") then</p><p>clearances will be reported from this line to all other lines.</p><p>The results are given for the nearest appropriate result point; see Line Results for details.</p><p>For the Range Graph and Range Graph Summary commands you can specify a range of arc lengths, e.g. "20 to 50".</p><p>You can also use ranges such as "<35" or ">60" to specify all arc lengths less than a point or all arc lengths greater</p><p>than a point.</p><p>For the Rayleigh Extremes instruction you can specify the parameters for the extreme value statistics analysis.</p><p>For the Duplicate Sheet instruction, the source worksheet is specified in this column.</p><p>For the Clear instruction, the range to be cleared is specified in this column.</p><p>If the value in this column is left empty</p><p>then the entire sheet is cleared.</p><p>Simulation Period</p><p>The period of simulation for which results are wanted. This can be Whole Simulation, Latest Wave, Static State,</p><p>Build up or a stage number (0 for the build-up, 1 for stage 1 etc.).</p><p>It can also be a specified period of simulation, given in the form "t1 to t2" where t1 and t2 are numeric time values</p><p>that are in the simulation and Simulation Start Time ≤ t1 ≤ t2 ≤ Simulation End Time. For example "20 to 30" or "-</p><p>12.5 to +35.7".</p><p>Note: If you use the Static State period then a single value will be reported – the value of the variable at</p><p>the very beginning of the simulation.</p><p>This cell should be left empty for the data output commands Select and Get Data and when outputting static results</p><p>using the Static Result, Range Graph and Range Graph Summary commands.</p><p>Note: This specified period format can be used to extract results at a single time point; for example the</p><p>period "27.4 to 27.4" will give the results at the nearest log sample to time 27.4.</p><p>Variable</p><p>The name of the output variable.</p><p>If the command is a results command (e.g. Time History, Range Graph, Linked Statistics, Min etc.) this should be set</p><p>to the same name as is used for the results variable in OrcaFlex. For example Effective Tension, Curvature, Surge,</p><p>etc.</p><p>If the command is Get Data then this is the batch script name of the data item.</p><p>If the command is Select then this is the wave train, draught, RAO direction or QTF direction to be selected.</p><p>4.4.4 Pre-defined commands</p><p>In the OrcaFlex Spreadsheet, the Command Cell can contain one of the following commands:</p><p> Load.</p><p> OrcFxAPI version.</p><p> Working Directory.</p><p> Warnings.</p><p> Clear, Duplicate Sheet.</p><p> Sample Times.</p><p> Time History.</p><p> Min, Max, Mean, Standard Deviation.</p><p> Linked Statistics.</p><p> Rayleigh Extremes.</p><p>w Automation, Post-processing</p><p>113</p><p> Spectral Density, Empirical Distribution, Rainflow Half Cycles, Rainflow Half Cycle Count.</p><p> Static Result.</p><p> Spectral Response Graph.</p><p> Range Graph, Range Graph Summary, Range Graph Min, Range Graph Max.</p><p> Get Data, Select.</p><p>4.4.5 Basic commands</p><p>Load <file name></p><p>This command tells the spreadsheet to open the specified file. Subsequent results extraction commands then apply</p><p>to that file.</p><p>You can either specify the full path of the file, for example:</p><p>Load c:\Project100\Case1.sim</p><p>or else use a relative path (relative to the directory containing the spreadsheet). The latter is often more convenient.</p><p>For example if the file Case1.sim is in the same directory as the spreadsheet then you can use the command:</p><p>Load Case1.sim</p><p>and this has the advantage that there is no need to alter the spreadsheet if the directory is renamed or the files are</p><p>moved to a different directory.</p><p>If you specify a data file (.dat or .yml) then the file is loaded and the OrcaFlex statics calculation is performed.</p><p>Subsequent results extraction gives results for the static configuration.</p><p>Simulation files (.sim) containing either static state results or dynamic simulation results can be loaded.</p><p>Note: The statics calculation may take a significant length of time. If the calculation time is excessively</p><p>long then we recommend that you use the Use Calculated Positions command when building your</p><p>model.</p><p>OrcFxAPI version</p><p>This outputs the version of the OrcFxAPI DLL which is being used by the spreadsheet. This is not necessarily the</p><p>version of the program which performed the calculations (for example if you load a simulation file which was</p><p>generated by a different version of OrcaFlex).</p><p>Working Directory</p><p>This outputs the directory where the spreadsheet is stored. If you are using relative paths then it can be useful to</p><p>keep track of the base path for QA purposes.</p><p>Warnings</p><p>This outputs the text from any warnings reported during the OrcaFlex calculations (static or dynamic). Simulations</p><p>run in batch mode or by Distributed OrcaFlex do not display such warnings since to do so would require user</p><p>intervention. This command allows you to check whether any such warnings were generated.</p><p>This command is the equivalent of the Calculation | View Warnings menu item.</p><p>Clear</p><p>This command clears the contents of cells in the specified output sheet. All cell formatting is preserved.</p><p>This should generally be the first command in the instructions sheet or the first command following a Load</p><p>command depending on whether the results are being output to a single or multiple sheets. Results extraction</p><p>spreadsheets are typically run repeatedly. The purpose of this command is to ensure that previously extracted</p><p>results are removed and so cannot get mixed up with the latest results.</p><p>If the Additional Data column is empty then the entire sheet is cleared. Otherwise, if the Additional Data column is</p><p>not empty, then its value is taken to mean a range of cells to be cleared. The range is specified using Excel's A1</p><p>reference style. The following table illustrates some typical A1 style references:</p><p>Reference Meaning</p><p>A1 Cell A1</p><p>Automation, Post-processing w</p><p>114</p><p>Reference Meaning</p><p>A1:B5 Cells A1 through B5</p><p>C5:D9,G9:H16 A multiple-area selection</p><p>A:A Column A</p><p>1:1 Row 1</p><p>A:C Columns A through C</p><p>1:5 Rows 1 through 5</p><p>1:1,3:3,8:8 Rows 1, 3, and 8</p><p>A:A,C:C,F:F Columns A, C, and F</p><p>Duplicate Sheet</p><p>This command copies the entire contents of the worksheet named in the Additional Data column to the specified</p><p>output sheet. All charts, formulae, formatting etc. that exist in the source worksheet are copied.</p><p>4.4.6 Time History and related commands</p><p>Sample Times</p><p>Returns the time values that apply to the time history results. This command returns a column of N numbers, where</p><p>N is the number of OrcaFlex log samples that are in the specified simulation period. So if the output cell is set to G5</p><p>and there are 500 log samples in the simulation period, then the time values for those log samples will be written to</p><p>cells G5…G504.</p><p>Time History</p><p>Returns the time history values of the specified variable. This command returns a column of N numbers, as with the</p><p>Sample Times command.</p><p>Min, Max, Mean, Standard Deviation</p><p>Min return a single number, equalling the minimum value of the specified time history variable during the specified</p><p>simulation period. Similarly for Max, Mean and Standard Deviation (which can be abbreviated to Std Dev).</p><p>Linked Statistics</p><p>Outputs the same information as the Linked Statistics command on the OrcaFlex results form. In the variable column</p><p>of the instruction you should specify a number of results variable names, separated by commas. The command</p><p>outputs a table of statistics for those variables.</p><p>Rayleigh Extremes</p><p>Outputs the results of a Rayleigh distribution Extreme Value Statistics analysis: MPM and Extreme Value with Risk</p><p>Factor. Parameters for the analysis are specified in the Additional Data column, separated by semi-colons. For</p><p>example:</p><p>StormDuration=3; RiskFactor=1; ExtremesToAnalyse=Upper tail</p><p>The storm duration is given in hours and the risk factor is a percentage.</p><p>The StormDuration and ExtremesToAnalyse parameters can be omitted. If they are omitted then default values</p><p>of 3 and Upper tail are used. If the RiskFactor parameter is omitted then the Extreme Value with Risk Factor</p><p>result is not output.</p><p>Spectral Density, Empirical Distribution, Rainflow Half Cycles, Rainflow Half Cycle Count</p><p>These commands extract spectral density, empirical distribution and rainflow half cycles results of the specified</p><p>variable.</p><p>Static Result</p><p>Returns the value of the specified variable. This command reports the value in the static configuration.</p><p>Spectral Response Graph</p><p>Returns the spectral response graph for the specified variable. The command returns two columns of numbers. The</p><p>first column is frequency and the second is the RAO.</p><p>w Automation, Post-processing</p><p>115</p><p>4.4.7 Range Graph commands</p><p>Range Graph, Range Graph Summary, Range Graph Min,</p><p>Range Graph Max</p><p>These commands output, for the specified variable of a line, tables containing range graph results. They are available</p><p>for any line variable for which a range graph is available in OrcaFlex.</p><p>The Range Graph command gives a table having 7 columns, containing arc length, minimum, maximum, mean,</p><p>standard deviation, upper limit, and lower limit. For each point on the line a row is generated in the table containing</p><p>the statistics of the values that occurred at that point during the specified simulation period.</p><p>You can specify that only a subset of the columns are to be output. This is done by listing the columns to be output in</p><p>the Additional Data column. This is most easily done using the Instructions Wizard.</p><p>The Range Graph Summary command gives a table having two rows, one for the overall minimum and one for the</p><p>overall maximum. Each row has 4 cells; two are label cells and the other two contain the overall minimum (or</p><p>maximum) value that occurred at any point on the line during the specified simulation period, and the arc length at</p><p>which it occurred.</p><p>The Range Graph Min and Range Graph Max commands output just the overall minimum or maximum value</p><p>respectively.</p><p>If you have loaded a simulation file then you must specify, in the Simulation Period column of the instruction, the</p><p>period of simulation for which you want results. Otherwise, if you have loaded a data file, you should leave this</p><p>column blank and the results for the static configuration are reported.</p><p>If the Additional Data column in the instruction is left blank then the results will apply to the whole line.</p><p>You can restrict these commands to only cover part of the line, by specifying a range of arc lengths, e.g. "20 to 50", in</p><p>the Additional Data column. The table will then only include results for points whose arc length is within the</p><p>specified range. You can also use ranges such as "<35" or ">60" to specify all arc lengths less than a point or all arc</p><p>lengths greater than a point. The length units used must be the same as those used in the OrcaFlex simulation file.</p><p>Alternatively, you can specify a section number in the Additional Data column to restrict results to that section.</p><p>4.4.8 Data commands</p><p>Get Data, Select</p><p>This command outputs the value of a data item. The object is specified in the Object Name column of the instruction</p><p>sheet and the data item is specified in the variable column.</p><p>The data item is specified using the batch script name of the data item. If the data item appears in a table in</p><p>OrcaFlex, then its row number must be given. The row number follows the data item name and is given as an index</p><p>enclosed by either square or round brackets (don't mix them on the same line). The index is always 1-based – i.e. [1]</p><p>is the first row of the table. For example if you wanted to output the number of segments in the 3rd section of a line</p><p>then the variable cell would be "NumberOfSegments[3]". For more details see batch script assignment.</p><p>Certain objects require special select commands to output certain data items. For example if you want to output</p><p>wave train data for the Environment and there is more than one wave train then you need to specify the particular</p><p>wave train. Likewise certain vessel type data requires you to specify a draught and/or an RAO type and direction.</p><p>Example commands to do this are given below:</p><p>Command Object Name Additional</p><p>Data</p><p>Simulation</p><p>Period</p><p>Variable</p><p>Select WaveTrain Environment Wave2</p><p>Get Data Environment WaveTrainType</p><p>Select WaveTrain Environment Wave3</p><p>Get Data Environment WaveTrainType</p><p>Select Draught VType1 Draught3</p><p>Get Data VType1 CurrentCoeffSurgeArea</p><p>Select RAOs VType1 Displacement</p><p>Select Direction VType1 30</p><p>Get Data VType1 RAOSwayAmplitude[3]</p><p>Automation, Post-processing w</p><p>116</p><p>Command Object Name Additional</p><p>Data</p><p>Simulation</p><p>Period</p><p>Variable</p><p>Select Direction VType1 60</p><p>Get Data VType1 RAOSwayAmplitude[2]</p><p>Select RAOs VType1 QTF</p><p>Select Direction VType1 45</p><p>Get Data VType1 RAOSurgeAmplitude[6]</p><p>Notes: The Select commands must be issued before the Get Data commands.</p><p>The Select commands are only needed for certain data items. For example the sea density data item</p><p>does not depend on wave train so it would not need a Select WaveTrain command.</p><p>4.4.9 Instructions Wizard</p><p>The Instructions Wizard allows you to create OrcaFlex spreadsheet instructions interactively. In many ways it is</p><p>the equivalent of the Select Results form in OrcaFlex. The Instructions Wizard is found on the OrcaFlex menu in the</p><p>spreadsheet.</p><p>Instructions Wizard Tutorial</p><p>For a quick introduction to the Instructions Wizard we recommend the following tutorial.</p><p>Prepare a simple OrcaFlex simulation file and an empty OrcaFlex spreadsheet</p><p>For the purpose of this example you need a simulation file containing at least a vessel and a line. You could use one</p><p>of the standard OrcaFlex examples – see www.orcina.com/SoftwareProducts/OrcaFlex/Examples.</p><p>Now create an OrcaFlex spreadsheet and save it in the same directory as the simulation file. The spreadsheet should</p><p>now looks like this:</p><p>Figure: Empty instructions table</p><p>Add a Load instruction using the Wizard</p><p>The instructions wizard creates and inserts instructions on the currently selected row. So the next step is to select</p><p>the first instruction row by clicking on a cell in row 5. Then open the Instruction Wizard by clicking on the OrcaFlex</p><p>menu and selecting "Instructions Wizard".</p><p>In the Instructions Wizard click the drop down button and change the command to "Load". A file name field and a</p><p>browse button will now appear. Click the browse button and select the simulation file you saved in the first part of</p><p>this tutorial. The top part of the Instructions Wizard should now look as follows:</p><p>http://www.orcina.com/SoftwareProducts/OrcaFlex/Examples</p><p>w Automation, Post-processing</p><p>117</p><p>Figure: Load instruction in the Instructions Wizard</p><p>To add the instruction to the spreadsheet click the "Accept and Close" button and the spreadsheet should now look</p><p>as follows:</p><p>Figure: Load instruction on the Instructions Sheet</p><p>The Load instruction tells the spreadsheet to open the specified file.</p><p>Add results instructions using the Wizard</p><p>Now we need to add some more instructions which specify which results to extract from this simulation file. Open</p><p>the Instructions Wizard again and change the command to "Time History". In the Object list select an OrcaFlex Line</p><p>(if you are using the "A01 Catenary Riser.sim" example then select 10" Cat Constant EA) and then select Effective</p><p>Tension from the Variable list.</p><p>This time, to add the instruction click the "Accept and go to Next Row" button. You will see the instruction being</p><p>added to the worksheet but the Instructions Wizard will remain open allowing you to add yet more instructions.</p><p>More than one instruction can be added at once. Suppose that you want time histories of X, Y and Z for the line.</p><p>Select these from the Variable list using CTRL+CLICK or SHIFT+CLICK. The Variable list now looks as follows:</p><p>Figure: Multiple selection of results variables</p><p>Automation, Post-processing w</p><p>118</p><p>Now click the "Accept and go to Next Row" button and you will see 3 instructions being added, one for each variable.</p><p>Now close the Wizard (by clicking the "Close" button) and process all the instructions. You should see 4 time</p><p>histories output on a new worksheet called "Results".</p><p>Setting Period and Additional Data for the instructions</p><p>The instructions added so far all specify the default simulation period of "Whole Simulation" and the default line</p><p>position of "Arclength 0".</p><p>In the Wizard you can specify a different simulation period by changing the Period drop down list. The available</p><p>options are: "Whole Simulation", "Latest Wave", "Specified Period", "Static State", "Build Up" and each stage of the</p><p>simulation, e.g. "0" (same as "Build Up"), "1". Try selecting different simulation periods</p><p>program that any text files specified on the command line contain a list of files to include</p><p>in the batch calculation. The command line can contain more than one file list. Text files within the file list will</p><p>be treated as batch script files.</p><p>Process Priority switches</p><p>These switches determine the processing priority of OrcaFlex. The available switches are /RealtimePriority,</p><p>/HighPriority, /AboveNormalPriority, /NormalPriority, /BelowNormalPriority, /LowPriority.</p><p>ThickLines switch</p><p>The /ThickLines switch allows you to specify a minimum thickness for lines drawn on OrcaFlex 3D View windows.</p><p>For example using the switch /ThickLines=5 forces OrcaFlex to draw all lines at a thickness of at least 5. If no value</p><p>is specified (i.e. the switch is /ThickLines) then the minimum thickness is taken to be 2.</p><p>This switch has been added to make OrcaFlex 3D Views clearer when projected onto a large screen.</p><p>ThreadCount switch</p><p>The /ThreadCount switch allows you to set the number of execution threads used by OrcaFlex for parallel</p><p>processing. For example /ThreadCount=1 forces OrcaFlex to use a single execution thread which has the effect of</p><p>disabling parallel processing.</p><p>1.3 PARALLEL PROCESSING</p><p>Machines with multiple processors or processors with multiple cores are becoming increasingly common. OrcaFlex</p><p>can make good use of the additional processing capacity afforded by such machines. For up to date information on</p><p>hardware choice for OrcaFlex please refer to www.orcina.com/Support/Benchmark.</p><p>OrcaFlex performs the calculations of the model's Line objects in parallel. This means that, interactively at least,</p><p>performance is only improved for models with more than one Line object. However, for models with more than one</p><p>Line performance is significantly improved.</p><p>Batch processing, fatigue analysis and OrcaFlex spreadsheet post-processing tasks process jobs and load cases</p><p>concurrently, using all available processing resources.</p><p>Thread count</p><p>OrcaFlex manages a number of execution threads to perform the parallel calculations. The number of these threads</p><p>(the thread count) defaults to the number of logical processors available on your machine, as reported by the</p><p>operating system. This default will work well for most cases. Should you wish to change it you can use the Tools | Set</p><p>Thread Count menu item. The thread count can also be controlled by a command line switch.</p><p>http://www.orcina.com/Support/Benchmark</p><p>w Introduction, Distributed OrcaFlex</p><p>15</p><p>1.4 DISTRIBUTED ORCAFLEX</p><p>Distributed OrcaFlex is a suite of programs that enables a collection of networked, OrcaFlex licensed computers to</p><p>run OrcaFlex jobs, transparently, using spare processor time. For more information about Distributed OrcaFlex</p><p>please refer to www.orcina.com/Support/DistributedOrcaFlex. Distributed OrcaFlex can be downloaded from this</p><p>address.</p><p>OrcaFlex can also make use of machines with multiple processors using parallel processing technology.</p><p>1.5 ORCINA LICENCE MONITOR</p><p>The Orcina Licence Monitor (OLM) is a service that monitors the current number of OrcaFlex licences claimed on a</p><p>network in real time. Other programs that use the OrcaFlex programming interface (OrcFxAPI) such as Distributed</p><p>OrcaFlex and the OrcaFlex spreadsheet are also monitored. You can obtain information on each licence claimed that</p><p>includes:</p><p> Network information: the computer name, network address and the user name.</p><p> Licence information: the dongle name, the dongle type (network or local) and the time the licence was claimed.</p><p> Program information: which modules are being used, the version, and the location of the program which has</p><p>claimed the licence (usually this is OrcaFlex.exe but it can be Excel.exe for the OrcaFlex spreadsheet for</p><p>example).</p><p>OLM can be downloaded from www.orcina.com/Support/OrcinaLicenceMonitor.</p><p>1.6 DEMONSTRATION VERSION</p><p>For an overview of OrcaFlex, see the Introduction topic and the tutorial.</p><p>The demonstration version of OrcaFlex has some facilities disabled – you cannot calculate statics or run simulation,</p><p>and you cannot save files, print, export or copy to the clipboard. Otherwise the demonstration version is just like the</p><p>full version, so it allows you to see exactly how the program works.</p><p>In particular the demonstration version allows you to open any prepared OrcaFlex data or simulation file. If you</p><p>open a simulation file then you can then examine the results, see replays of the motion etc. There are numerous</p><p>example files provided on the demonstration disc. These example files are also available from</p><p>www.orcina.com/SoftwareProducts/OrcaFlex/Examples.</p><p>If you have the full version of OrcaFlex then you can use the demonstration version to show your customers your</p><p>OrcaFlex models and results for their system. To do this, give them the demonstration version and copies of your</p><p>OrcaFlex simulation files. The demonstration version can be downloaded from</p><p>www.orcina.com/SoftwareProducts/OrcaFlex/Demo.</p><p>1.7 ORCAFLEX EXAMPLES</p><p>OrcaFlex is supplied with an examples disc containing a comprehensive collection of example files. These examples</p><p>can also be found at www.orcina.com/SoftwareProducts/OrcaFlex/Examples.</p><p>1.8 VALIDATION AND QA</p><p>The OrcaFlex validation documents are available from www.orcina.com/SoftwareProducts/OrcaFlex/Validation.</p><p>1.9 ORCINA</p><p>Orcina is a creative engineering software and consultancy company staffed by mechanical engineers, naval</p><p>architects, mathematicians and software engineers with long experience in such demanding environments as the</p><p>offshore, marine and nuclear industries. As well as developing engineering software, we offer a wide range of</p><p>analysis and design services with particular strength in dynamics, hydrodynamics, fluid mechanics and</p><p>mathematical modelling.</p><p>http://www.orcina.com/Support/DistributedOrcaFlex</p><p>http://www.orcina.com/Support/OrcinaLicenceMonitor</p><p>http://www.orcina.com/SoftwareProducts/OrcaFlex/Examples/</p><p>http://www.orcina.com/SoftwareProducts/OrcaFlex/Demo/</p><p>http://www.orcina.com/SoftwareProducts/OrcaFlex/Examples</p><p>http://www.orcina.com/SoftwareProducts/OrcaFlex/Validation</p><p>Introduction, References and Links w</p><p>16</p><p>Contact Details</p><p>Orcina Ltd.</p><p>Daltongate</p><p>Ulverston</p><p>Cumbria</p><p>LA12 7AJ</p><p>UK</p><p>Telephone: +44 (0) 1229 584742</p><p>Fax: +44 (0) 1229 587191</p><p>E-mail: orcina@orcina.com</p><p>Web Site: www.orcina.com</p><p>Orcina Agents</p><p>We have agents in many parts of the world. For details please refer to www.orcina.com/ContactOrcina.</p><p>1.10 REFERENCES AND LINKS</p><p>References</p><p>API, 1993. API RP 2A-WSD, Recommended Practice for Planning, Designing and Constructing Fixed Offshore</p><p>Platforms – Working Stress Design. American Petroleum Institute.</p><p>API, 2000. API RP 2A-WSD, Recommended Practice for Planning, Designing and Constructing Fixed Offshore</p><p>Platforms – Working Stress Design. American Petroleum Institute.</p><p>API, 1998. API RP 2RD, Design of Risers for Floating Production Systems and Tension-Leg Platforms. American</p><p>Petroleum Institute.</p><p>API, 2005. API RP 2SK, Design and Analysis of Stationkeeping Systems for Floating Structures. American Petroleum</p><p>Institute.</p><p>API. Comparison of Analyses of Marine Drilling Risers. API Bulletin. 2J.</p><p>Aranha J A P, 1994. A formula for wave drift damping in the drift of a floating body. J. Fluid Mech. 275, 147-155.</p><p>Aubeny C, Biscontin G and Zhang J, 2006. Seafloor interaction with steel catenary risers. Offshore Technology</p><p>Research Center (Texas A&M University) Final Project Report (http://www.mms.gov/tarprojects/510.htm).</p><p>Aubeny C, Gaudin C and Randolph M, 2008. Cyclic Tests of Model Pipe in Kaolin. OTC 19494, 2008.</p><p>Barltrop N D P and Adams A J, 1991. Dynamics of fixed marine structures. Butterworth Heinemann for MTD. 3rd</p><p>Edition.</p><p>Batchelor G K, 1967. An introduction to fluid dynamics. Cambridge University Press.</p><p>Bellanger M, 1989. Digital Processing of Signals. Wiley.</p><p>Blevins R D, 2005. Forces on and Stability of a Cylinder in a Wake. J. OMAE, 127, 39-45.</p><p>Bridge C, Laver K, Clukey E, Evans</p><p>and adding instructions.</p><p>Notice how the values in the Simulation Period column reflect your selections in the Wizard.</p><p>For OrcaFlex Lines you also need to specify a point on the line, e.g. End A, End B, arc length 50, node 12 etc. All these</p><p>options are available in the Wizard when you are specifying results for a line.</p><p>In addition, certain results require extra information.</p><p> If you are extracting clearance results for Lines then you need to specify the clearance line.</p><p> If you are extracting stress component results for Lines then you need to specify the cross-sectional position.</p><p> If you are extracting Wing results for 6D Buoys then you need to specify the wing.</p><p> If you are extracting results for Winches then you may need to specify the winch connection point.</p><p> If you are extracting results for the Environment then you need to specify the position at which you want results</p><p>reported.</p><p>Other commands</p><p>So far we have just looked at time history results but the Wizard allows you to build other instructions. For example,</p><p>open the Wizard again and change the command to Range Graph. Notice how slightly different options are available</p><p>reflecting the fact that range graphs are specified in a slightly different way from time histories.</p><p>Try also experimenting with other commands like Linked Statistics, Sample Times, Spectral Density, Max, Standard</p><p>Deviation and so on.</p><p>There are even commands for reporting model data: Select and Get Data.</p><p>Labels, sheet name, output cell</p><p>The one part of the Instructions Wizard which we have not discussed is the section titled "Labels" as shown below:</p><p>Figure: Labels section of the Instruction Wizard</p><p>This section determines what gets written into the first 4 columns of the instructions table, namely Sheet Name,</p><p>Label Cell, Label and Output Cell.</p><p>If the Overwrite option is checked then the Wizard will output values in each of these 4 columns as specified in the</p><p>relevant field. If not checked then the values in the sheet will remain unchanged.</p><p>w Automation, Post-processing</p><p>119</p><p>You can choose to use a default label, in which case the label will be assembled based on the particular instruction it</p><p>is associated with. Alternatively you can choose to specify the label yourself.</p><p>When instructions are added the Label Cell and Output Cell values on the Instructions Wizard will be incremented</p><p>automatically. This automatic procedure will not always produce the values you require. However, it generally gives</p><p>a good first effort which you can modify later.</p><p>Exclude header text</p><p>Some results, for example range graphs, linked statistics, spectral density etc., produce output that includes column</p><p>headers. There are situations where these column headers are undesirable and if that is so the "Exclude header text"</p><p>box can be checked to suppress their output.</p><p>4.4.10 Duplicate Instructions</p><p>The Duplicate Instructions form allows you to duplicate sets of OrcaFlex spreadsheet instructions for multiple load</p><p>cases.</p><p>Suppose you are analysing a number of different load cases for a variety of environmental conditions. Once you have</p><p>built the spreadsheet instructions for a single load case you typically want to generate the same instructions for</p><p>each other load case. The Duplicate Instructions form automates this procedure.</p><p>The Duplicate Instructions form can be found on the OrcaFlex menu in the spreadsheet. Before using it you should</p><p>create a set of instructions for the first load case – an example is shown below:</p><p>Figure: Instructions table with instructions for a single load case</p><p>You are now ready to use the Duplicate Instructions form. When it first opens it looks as follows:</p><p>Automation, Post-processing w</p><p>120</p><p>Figure: The Duplicate Instructions form</p><p>Simulation file selection</p><p>If your load case files (either OrcaFlex simulation files or OrcaFlex data files) are generated by an OrcaFlex batch</p><p>script then you should set this option to From Script File and select the script file using the Browse button or by</p><p>typing the file name into the "Script File Name" field. A duplicate set of instructions is generated for each file which</p><p>is written by the script file. We strongly recommend that you use this option since script files make QA much more</p><p>manageable.</p><p>Alternatively, if your load case files are generated by some other means then you can choose the Specified option</p><p>and you will then be able to specify each load case file directly.</p><p>Duplication Method</p><p>Usually you will want results for each load case to appear on separate sheets. To do this you set this option to</p><p>Different Sheets. The results sheets will be assigned names based on the Sheet Names by option. If you select the</p><p>Load Case option then results sheets will be named based on the load case file name. If you select the Index option</p><p>then sheets will be named 1, 2, 3 etc. In addition, you may specify a prefix for the sheet name by filling in the Sheet</p><p>Base Name field.</p><p>Sometimes, however, it is desirable for all the results to appear on a single sheet – this is achieved with the Single</p><p>Sheet option. The duplication process will generate new instructions with the same Sheet Name.</p><p>When you select the Single Sheet option you must also specify row and column offsets. These offsets allow you to</p><p>avoid the results from each load case overwriting other load case results. Suppose that the results from the first load</p><p>case took up 20 rows worth of space. In this case you would probably specify a row offset of 22 (to allow 2 blank</p><p>rows between load case results) and a column offset of 0.</p><p>When the selected duplication method is Single Sheet, you also have the option whether to Duplicate Labels.</p><p>When checked, the instruction’s labels are duplicated in the same way as the Different Sheets method, but also</p><p>updated with the given row and column offsets. If not checked then no labels are duplicated allowing you to extract</p><p>the results from multiple load cases to a single sheet that has only a single set of labels.</p><p>Duplicating the instructions</p><p>Once you have decided exactly how the instructions are to be duplicated you click the Duplicate button and the</p><p>instructions table will be modified to look something like this:</p><p>w Automation, Post-processing</p><p>121</p><p>Figure: Instructions table with duplicated instructions for multiple load cases</p><p>Adding / removing instructions</p><p>Quite often you will find yourself wanting to add more instructions to the each load case. The easiest way to do this</p><p>is to delete all the instructions apart from those of the first load case. In the screenshot above this would mean</p><p>deleting all cells from row 9 and below. You can then add more instructions to the first load case. Finally you simply</p><p>repeat the duplication process outlined above and you will have the extra instructions for each load case.</p><p>w Theory, Coordinate Systems</p><p>123</p><p>5 THEORY</p><p>5.1 COORDINATE SYSTEMS</p><p>OrcaFlex uses one global coordinate system GXYZ, where G is the global origin and GX, GY and GZ are the global axes</p><p>directions. In addition, there are a number of local coordinate systems, generally one for each object in the model. In</p><p>general we use Lxyz to denote a local coordinate system. Another coordinate system that we make widespread use</p><p>of is the Line End orientation which we denote Exyz.</p><p>All the coordinate systems are right handed, as shown in the following figure, which shows the global axes and a</p><p>vessel with its own local vessel axes Vxyz. Positive rotations are clockwise when looking in the direction of the axis</p><p>of rotation.</p><p>z</p><p>Sea Surface</p><p>Z</p><p>Y</p><p>X</p><p>G</p><p>V</p><p>y</p><p>x</p><p>Vessel Axes</p><p>Global Axes</p><p>Figure: Coordinate Systems</p><p>The global frame of reference must be a right-handed system and its Z-axis GZ must be positive upwards, but</p><p>otherwise it is chosen by the user. You can therefore choose the position of the global origin G and the horizontal</p><p>direction GX according to what suits the problem being analysed.</p><p>The local coordinate systems</p><p>for each type of object are described in the section about that object, but typically the</p><p>origin is at a selected fixed point on the object and the axes are in special fixed directions, such as the surge, sway</p><p>and heave directions for a vessel. The seabed also has its own seabed origin and local axes, with respect to which the</p><p>seabed shape is defined.</p><p>The local axes are distinguished from the global axes by using lower case; for example the local object directions are</p><p>referred to as x, y and z . The global directions are referred to as the X, Y and Z. Whenever data or results are</p><p>coordinate system dependent, they are referred to as being either global-relative (and are labelled in upper case) or</p><p>object-relative (and are labelled in lower case).</p><p>You can ask OrcaFlex to draw the local axes on the 3D view. This enables you to see the local axes and check that</p><p>they are as wanted.</p><p>Most of the data and results are given relative to the global axes, including:</p><p> Data defining the sea, such as the mean sea surface Z level and the current and wave direction.</p><p> The positions of objects; for example the position of the vessel is defined by giving the global coordinates of the</p><p>vessel origin V.</p><p>The most common object-relative items are:</p><p>Theory, Direction Conventions w</p><p>124</p><p> The coordinates of points that move with the object, such as the vertices of a vessel or the connection point</p><p>when something is connected to a buoy.</p><p> The direction-dependent properties of objects, such as drag and added mass coefficients, moments of inertia,</p><p>etc.</p><p>5.2 DIRECTION CONVENTIONS</p><p>Directions and Headings</p><p>Directions and headings are specified in OrcaFlex by giving the azimuth angle of the direction, in degrees, measured</p><p>positive from the x-axis towards the y-axis, as shown in the following figure.</p><p>y</p><p>x 0</p><p>30150</p><p>330</p><p>180</p><p>270</p><p>90</p><p>210</p><p>Directions relative</p><p>to axes</p><p>Figure: Directions and Headings</p><p>Directions for waves, current and wind are specified by giving the direction in which the wave (or current or wind)</p><p>is progressing, relative to global axes. In other words for these directions the x and y-axes in the above figure are the</p><p>global GX and GY axes.</p><p>Vessel headings are specified as the direction in which the vessel Vx-axis is pointing, relative to global axes. So again,</p><p>for vessel headings the x and y-axes in the above figure are the global GX and GY axes.</p><p>Vessel responses to waves, and similarly for current and wind, depend on the wave direction relative to the vessel.</p><p>For example, vessel type RAOs and QTFs are given for a specified wave direction relative to vessel axes</p><p>(β = Wave Direction relative to global axes - Vessel Heading). In other words for these vessel-relative directions the</p><p>x axis in the above figure is in the vessel heading direction. Hence a relative wave direction of β=0° means a wave</p><p>coming from astern and a relative direction of β=90° means one coming from starboard.</p><p>The slope direction for the seabed is specified as the direction that points up the steepest slope, relative to global</p><p>axes.</p><p>The slope direction of a plane shape that is Fixed or Anchored is specified relative to global axes.</p><p>The slope direction of a plane shape that is connected to another object is specified relative to that object's axes.</p><p>Azimuth and Declination</p><p>Directions are defined in OrcaFlex by giving two angles, azimuth and declination, that are broadly similar to those</p><p>used in navigation, gunnery, etc. As with positions, directions are sometimes defined relative to the global axes and</p><p>sometimes relative to the local object axes.</p><p>For directions defined relative to the object axes Oxyz, the azimuth and declination angles are defined as follows:</p><p> Azimuth is the angle from the x axis to the projection of the direction onto the xy plane. The positive x axis</p><p>direction therefore has Azimuth = 0°, and the positive y axis direction has Azimuth = 90°.</p><p> Declination is the angle the direction makes with the z axis. Therefore Declination is 0° for the positive z-</p><p>direction, 90° for any direction in the xy plane, and 180° for the negative z-direction. When Declination is 0° or</p><p>180°, Azimuth is undefined (OrcaFlex reports Azimuth = 0° in these cases).</p><p>w Theory, Object Connections</p><p>125</p><p>Directions relative to the global axes are defined in just the same way, simply replacing the local xyz directions</p><p>above with the global XYZ directions. A global declination of 0° therefore means vertically upwards, 90° means</p><p>horizontal and 180° means vertically downwards.</p><p>When a direction is being defined, the "sign" of the direction must also be defined. For example "vertical" does not</p><p>fully define a direction – it must be either "vertically up" or "vertically down" before the azimuth and declination</p><p>angles can be derived. The "sign" conventions used in OrcaFlex for directions are:</p><p> For Lines, axial directions are always defined in the A to B sense, in other words from End A towards End B.</p><p>Thus a vertical line with End A at the top has declination 180°.</p><p> For Winches and Links, axial directions are defined in the sense 'from first end towards second end'. Thus a link</p><p>with end 1 directly above end 2 has declination 180°.</p><p>5.3 OBJECT CONNECTIONS</p><p>Lines, links, winches and shapes are special objects that can be connected to other objects. First consider connecting</p><p>a line to another object. To enable connections to be made each line has two joints, one at each end, which are</p><p>drawn as small blobs on the ends of the line, when the model is in Reset state. To distinguish the two ends, the joint</p><p>at End A is drawn as a triangle and the joint at End B as a square.</p><p>Each of these line end joints can either be Free or else be connected to a Vessel, 3D Buoy, 6D Buoy, the Global Axes</p><p>or the seabed. Lines cannot be connected to themselves, to other lines, nor to a Link or Winch. When a line's joint is</p><p>Free, that end of the line is free to move and this is indicated by the joint being drawn in the same colour as the line.</p><p>When the joint is connected to another object, that end of the line becomes a slave and the object to which it is</p><p>connected becomes its master. The connection is then indicated by the joint being drawn in the colour of its master.</p><p>Links and Winches also have joints at each end (winches can also have extra intermediate joints) and these are</p><p>connected to other objects in the same way as with lines, but with the following exceptions.</p><p> Link and winch joints cannot be Free – they must always be connected to some master.</p><p> Link and winch joints can be connected to nodes on a line, as well as to Vessels, 3D Buoys, 6D Buoys, the Global</p><p>Axes or the seabed. This allows, for example, a winch to be attached to the end node of a line so that winching in</p><p>or out can be modelled.</p><p>Shapes have a single joint which can be connected to Vessels, 3D Buoys, 6D Buoys, the Global Axes or the seabed.</p><p>When a joint is connected to a master, the connection is made at a specified master-relative position and the master</p><p>object then determines the position of its slave – the slave is dragged around by its master as the master moves. In</p><p>response the slave applies forces and moments to its master – for a line these are simply the end force and moment</p><p>applied by the line.</p><p>Because neither the Global Axes nor the seabed move, a joint connected to either of them is simply fixed in one</p><p>position. The difference between them lies in how the connection point is specified. For a connection to the Global</p><p>Axes, the X, Y and Z coordinates of the connection point are specified relative to those axes and the joint is called</p><p>Fixed. For a connection to the seabed the X and Y coordinates are specified relative to the global axes, but the Z</p><p>coordinate is specified relative to the seabed Z level at that X,Y position; the joint is then referred to as being</p><p>Anchored. So for an Anchored joint, Z=0 means that the connection is exactly on the seabed and Z=1 means it is 1</p><p>unit above the</p><p>seabed. By using anchored joints you can therefore avoid the need to calculate the seabed Z level at</p><p>the given X,Y position (not simple with sloping seabeds).</p><p>5.4 INTERPOLATION METHODS</p><p>OrcaFlex uses a number of different methods for interpolating data. These methods are described below:</p><p> Linear. The data is assumed to follow a straight line between each (X,Y) pair. Linear interpolation is said to be</p><p>piecewise linear. Curves that are linearly interpolated are continuous but their first derivative is discontinuous</p><p>at each X data point.</p><p> Cubic spline. Cubic spline interpolation fits a cubic polynomial over each interval in the data, so the fitted</p><p>interpolation curve is piecewise cubic. These cubics are chosen so that both the first and second derivatives are</p><p>continuous at each X data point. A consequence of this is that with cubic polynomial interpolation the (X,Y) data</p><p>specified at any given data point affects the interpolated curve over the whole range of X values, not just over</p><p>the intervals near that (X,Y) data point. In other words cubic spline gives a 'non-local' interpolation.</p><p>Theory, Interpolation Methods w</p><p>126</p><p> Cubic Bessel (also known as Parabolic Blending). Cubic Bessel interpolation is similar to cubic spline in that it</p><p>is also piecewise cubic. But for this method the cubics are chosen so that the only the first derivative is</p><p>continuous at each X data point. The second derivative is not, in general, continuous at the data points, which</p><p>can be a drawback for some purposes. However cubic Bessel interpolation has the advantage that it gives 'local'</p><p>interpolation – i.e. the (X,Y) values at any given data point only affects the interpolated curve over the intervals</p><p>near that point.</p><p>Choosing interpolation method</p><p>Sometimes OrcaFlex provides a choice of interpolation method. In general we would recommend that you use the</p><p>default interpolation method, but in some cases it may be appropriate to use a different method. To decide you need</p><p>to take into account what the interpolated data is used for and the different properties of the interpolation methods.</p><p>If continuity of first derivative is not required then linear interpolation is often appropriate. It has the advantage</p><p>that it is very simple. The other 2 methods are piecewise cubic and they both produce a smooth curve, i.e. one with</p><p>continuous first derivative. Cubic spline interpolation gives a curve that also has a continuous second derivative,</p><p>whereas cubic Bessel does not, but in many cases this is not important.</p><p>Both cubic spline and cubic Bessel produce curves that often have overshoots. For example the following graphs</p><p>show how each method interpolates a particular set of data. Although the greatest Y value specified in the data is 8,</p><p>the interpolated curves for cubic spline and cubic Bessel both exceed this value. How serious this overshoot is</p><p>depends on the data – it can be much more serious than illustrated here or sometimes there can be no problem at</p><p>all. The amount of overshoot is generally less with cubic Bessel than with cubic spline. But if you are using either of</p><p>the piecewise cubic interpolation methods then you should always check whether the interpolated curve gives an</p><p>appropriate fit to the data. If it does not then you usually need to supply more data points.</p><p>w Theory, Static Analysis</p><p>127</p><p>Finally, cubic Bessel interpolation has the advantage that it gives a 'local' interpolation, in the sense that each</p><p>specified (X,Y) data point only affects the interpolated curve over the intervals near that point, whereas with cubic</p><p>spline the whole curve is affected to some extent by each of the (X,Y) data points.</p><p>5.5 STATIC ANALYSIS</p><p>There are two objectives for a static analysis:</p><p> To determine the equilibrium configuration of the system under weight, buoyancy, hydrodynamic drag, etc.</p><p> To provide a starting configuration for dynamic simulation.</p><p>In most cases, the static equilibrium configuration is the best starting point for dynamic simulation and these two</p><p>objectives become one. However there are occasions where this is not so and OrcaFlex provides facilities for</p><p>handling these special cases. These facilities are discussed later.</p><p>Static equilibrium is determined in a series of iterative stages:</p><p>1. At the start of the calculation, the initial positions of the vessels and buoys are defined by the data: these in turn</p><p>define the initial positions of the ends of any lines connected to them.</p><p>2. The equilibrium configuration for each line is then calculated, assume the line ends are fixed.</p><p>3. The out of balance load acting on each free body (node, buoy, etc.) is then calculated and a new position for the</p><p>body is estimated. The process is repeated until the out of balance load on each free body is zero (up to the</p><p>specified tolerance). For details see Statics of Buoys and Vessels.</p><p>For the majority of systems, the static analysis process is very quick and reliable. Occasionally, usually for very</p><p>complex systems with multiple free bodies and many inter-connections, convergence may be difficult to achieve. To</p><p>help overcome this problem, OrcaFlex provides facilities for the user to suppress some of the degrees of freedom of</p><p>the system and approach the true equilibrium by a series of easy stages. See Statics of Buoys and Vessels.</p><p>Finally, the static analysis can also be turned into a steady state analysis by specifying non-zero starting velocity on</p><p>the General Data form. This is useful when modelling towed systems or other systems that have a steady velocity.</p><p>5.5.1 Line Statics</p><p>When you do a static analysis OrcaFlex does static analyses for each line in the model.</p><p>Note: The lines are analysed in the order they appear in the by types view of the model browser. So if you</p><p>are having a problem with the static analysis of a particular line, and there are a lot of lines in the</p><p>model, then you can make investigation of the problem easier by dragging the line up to the top of</p><p>the list in the model browser.</p><p>The static analysis of a given line has two steps:</p><p>Line Statics Step 1</p><p>The first step calculates a configuration of the line (i.e. positions for all the nodes on the line), using the method</p><p>specified on the line data form (either Catenary, Spline, Quick, Prescribed, or User Specified).</p><p>Theory, Static Analysis w</p><p>128</p><p>Line Statics Step 2</p><p>The second step, which is optional, is called Full Statics. If Full Statics is included, then it calculates the true</p><p>equilibrium position of the line. The calculation is iterative and hence it needs a starting configuration – for this it</p><p>uses the configuration found by step 1. If Full Statics is not included, then the line is simply left in the configuration</p><p>found by step 1, which (depending on the method chosen) may not be an equilibrium position.</p><p>Unstable equilibria</p><p>Sometimes Line Statics Step 2 finds an equilibrium configuration that is unstable. Everyday examples of unstable</p><p>equilibria include balancing a coin on its edge or balancing a pencil on its tip.</p><p>Very occasionally OrcaFlex statics converges on an unstable equilibrium. An unstable equilibrium can usually be</p><p>detected by the presence of large curvature spikes on a range graph. Typically a dynamic run will excite the line</p><p>enough to kick it out of the unstable equilibrium. However, statics and dynamics results from such unstable</p><p>equilibria are invalid.</p><p>Catenary</p><p>The Catenary method calculates the equilibrium position of the line, but it ignores the effects of bending and</p><p>torsional stiffness of the line or its end terminations.</p><p>The Catenary method also ignores contact forces between the line and any solid shapes in the model, but it does</p><p>include all other effects, including weight, buoyancy, axial elasticity, current drag and seabed touchdown (see</p><p>below) and friction.</p><p>Because bend stiffness (and other) effects are not included in the Catenary method, the position found is not, in</p><p>general, an equilibrium position.</p><p>Therefore Full Statics should normally be included unless it is known that the</p><p>omitted effects are unimportant. Nevertheless, the Catenary position is often quite close to the true equilibrium</p><p>position, especially when bend stiffness is not a major influence.</p><p>The Catenary algorithm is robust and efficient for most realistic cases but it cannot handle cases where the line is in</p><p>compression. This is because, when bending stiffness is ignored, compression means the line is slack and there is no</p><p>unique solution.</p><p>The algorithm is an iterative process that converges on the solution. If necessary, you can control the maximum</p><p>number of iterations that are attempted, as well as other aspects of the convergence process – see Catenary</p><p>Convergence.</p><p>The Catenary solution has facilities for including seabed touchdown, with the following limitations:</p><p> Seabed touchdown can only be included at End B of the line, not at End A. Therefore, if you want touchdown</p><p>then you should arrange it to be at End B.</p><p> Touchdown is only included if End B is anchored exactly on, or else below, the seabed. If End B is above the</p><p>seabed, even if only by a small amount, then no touchdown will be modelled and the line may hang below the</p><p>seabed. This will be corrected when the simulation starts, since the nodes below the seabed will be pushed back</p><p>up by the seabed reaction forces. Alternatively, you should use the Full statics option, which can handle this</p><p>case.</p><p> If End B is below the seabed, then the Catenary algorithm models touchdown by assuming that the line 'levels</p><p>out' at the level of End B. This will result in part of the line being below the seabed, but again this will be</p><p>corrected when the simulation starts, since the nodes below the seabed will be pushed back up by the seabed</p><p>reaction forces.</p><p>Spline</p><p>The Spline method gives the line an initial shape that is based on a user-defined smooth Bezier spline curve. It is</p><p>therefore not, in general, an equilibrium position, and so when it is used Full Statics should be included if you want</p><p>the equilibrium position to be found.</p><p>The Bezier curve is specified by the user giving a series of control points – it is a curve that tries to follow those</p><p>control points – and the Bezier curve and its control points (marked by +) can be seen on the 3D view when in Reset</p><p>state. The smoothness of the spline can be controlled using the spline order.</p><p>The Spline method puts the line into a position that, as far as possible, follows the Bezier curve. However the Bezier</p><p>curve may have the wrong length (depending on how accurately you have set up the control points), so the Spline</p><p>w Theory, Static Analysis</p><p>129</p><p>method scales the Bezier spline curve up or down until the resulting line shape has the correct As Laid Tension, as</p><p>specified on the line data form.</p><p>Quick</p><p>The Quick method simply leaves the line in the position that it was drawn when in Reset state. This is a crude</p><p>catenary shape that (for speed reasons) ignores most effects, including buoyancy, drag, bending and torsional</p><p>stiffness, and interaction with seabed and solids. In fact the position set by the Quick method only allows for the</p><p>line's average weight per unit length and axial elasticity, so it is not usually an equilibrium position (though for</p><p>simple cases it may be quite close). The Quick method should usually be used only as a preliminary to Full Statics.</p><p>Prescribed</p><p>The Prescribed method is intended primarily for pull-in analyses. It provides a convenient way of setting the line up</p><p>in the as laid (i.e. pre pull-in) starting position, ready for a time simulation of the pull-in. The starting shape of the</p><p>line is specified by defining a track on the seabed (see Prescribed Starting Shape). The track is defined as a sequence</p><p>of track sections each of which is a circular arc of user-specified length and angle of turn and the line is laid along</p><p>this track. See Laying out the Line.</p><p>Y</p><p>X</p><p>Start</p><p>of track</p><p>End A</p><p>Azimuth = 10</p><p>Track Section 1</p><p>Length = 150</p><p>Turn = 0 Track section 2</p><p>Length = 100</p><p>Turn = -90</p><p>Track section 3</p><p>Length = 100</p><p>Turn = 90</p><p>Track Section 4</p><p>Length = 150</p><p>Turn = 0</p><p>Continuation of</p><p>last track section</p><p>10</p><p>Figure: Plan View of Example Track</p><p>User Specified Starting Shape</p><p>The User Specified Starting Shape statics method involves no calculation. Instead you specify a position for each</p><p>node and the node is placed there. If torsion is modelled then node orientations can also be specified.</p><p>This statics method allows you to restart calculations using line configurations that have been calculated by</p><p>separate OrcaFlex calculations. For example you could perform an in-place analysis of a line using its configuration</p><p>as calculated by an earlier pull-in analysis.</p><p>To perform a restart this way you usually need to disable Full Statics and Whole System Statics. One way to do this is</p><p>to set the statics convergence tolerances to large values, e.g. 1e6.</p><p>Warning: We recommend that User Specified Statics is only used in this way to perform restarts. Full Statics</p><p>or Whole System Statics used in conjunction with User Specified Statics commonly results in slow</p><p>and troublesome statics convergence.</p><p>Full Statics</p><p>The Full Statics calculation is a line statics calculation that includes all forces modelled in OrcaFlex. In particular it</p><p>includes the effects of bend stiffness and interaction with shapes. These effects are omitted from the Catenary</p><p>calculation, and this sometimes results in significant shock loads at the start of the simulation, when the effects of</p><p>bend stiffness and shapes are introduced. Because the Full Statics calculation includes these effects, no such shock</p><p>loads should occur when it is used. We therefore recommend using Full Statics for most cases.</p><p>Content/html/Statics_of_Lines.htm</p><p>Theory, Static Analysis w</p><p>130</p><p>To use Full Statics set the Step 2 Statics Method to Full on the Line data form. Full statics needs a starting shape for</p><p>the line, and it uses the specified Step 1 Statics Method to obtain this; it then finds the equilibrium position from</p><p>there. You should therefore set the Step 1 Statics Method to give a reasonable starting shape, choosing either</p><p>Catenary, Prescribed, Quick or Spline.</p><p>Which Step 1 Statics Method you should choose depends on the model in question. In general you should choose the</p><p>method that gives the best initial estimate of the line's static position. For lines with no buoyant sections and no</p><p>interaction with shapes or the seabed, the Quick method may well suffice. If there is seabed interaction or a buoyant</p><p>section then Catenary might be better. For lines that interact with a shape, the Spline method is perhaps best since it</p><p>enables you to ensure that the line starts on the correct side of the shape.</p><p>Which method to use</p><p>The settings to use for the line data items Step 1 Statics Method and Step 2 Statics Method depend on the type of</p><p>system being modelled and the type of static position wanted.</p><p>The default settings (for a new line) are the Catenary method followed by Full Statics. This is often a good choice,</p><p>since the Catenary method is fast and in many case gives a good initial estimate of the equilibrium position. It</p><p>therefore often provides a good starting point for the Full Statics calculation, which then refines the position to take</p><p>into account the effects that the Catenary omits, such as bending and torsional stiffness and interaction with solids.</p><p>There are situations where you may need to use other settings. Some specific cases are described below, but first</p><p>here are some general points to bear in mind.</p><p>Full Statics should be included if you want the true equilibrium position to be found.</p><p>When Full Statics is included, the first stage Statics Method is only used to give the initial starting shape for Full</p><p>Statics. The choice of Statics Method is then, in principle, not important, since the final position found will be the</p><p>equilibrium position, irrespective of the initial starting</p><p>position. However it is normally best to choose the Statics</p><p>Method that gives the best initial estimate of the desired equilibrium position, since this will give the best starting</p><p>position for Full Statics to work from.</p><p>There are some cases where the choice of Statics Method is important. Firstly, in cases where there may be more</p><p>than one equilibrium position, the Full Statics calculation will tend to find the one that is closest to the initial starting</p><p>position found by the Statics Method. Secondly, the Full Statics calculation is iterative and may have difficulty</p><p>converging if the initial Statics Method position from which it starts is a long way from the true equilibrium position.</p><p>In both these situations, it is generally best to choose the Statics Method that gives the best initial estimate of the</p><p>desired equilibrium position.</p><p>Catenary convergence failure</p><p>The Catenary method is iterative and may fail to converge. It may be possible to solve this by adjusting the Catenary</p><p>Convergence Parameters on the line data form. If this proves difficult, then an alternative is to use one of the other</p><p>statics methods. The Quick method may suffice, or alternatively the Spline method may be needed. Providing Full</p><p>Statics is included then the final static position found will be the same.</p><p>Full Statics Convergence Failure</p><p>Full Statics is also an iterative calculation and may sometimes fail to converge. The convergence process is</p><p>controlled by the Full Statics Convergence Parameters on the line data form so it may be possible to obtain</p><p>convergence by adjusting some of those parameters.</p><p>However, the problem may be due to the initial starting position obtained by the specified statics method being a</p><p>long way from the equilibrium position. In this case it may be necessary for the user to specify the Spline statics</p><p>method and specify control points that give a good starting shape for the Full Statics.</p><p>Note: When setting up the spline control points, it is often useful to first set Full Statics to "No". This</p><p>allows you to examine and refine the spline shape, by running the static analysis and adjusting the</p><p>control points until the spline shape is close to the desired shape. You can then set Full Statics back</p><p>to "Yes" in order to find the true equilibrium position.</p><p>Contact With Solids</p><p>The Catenary and Quick methods both ignore contact with solids and so they may well give a poor initial position for</p><p>the Full Statics to work on. As a result the Full Statics calculation may fail to converge, or else converge to the wrong</p><p>equilibrium position (e.g. one in which the line is on the wrong side of the solid). In both these cases it may be better</p><p>w Theory, Dynamic Analysis</p><p>131</p><p>for the user to select the Spline method and then specify control points that give an initial shape that is close to the</p><p>desired equilibrium position.</p><p>Pipeline Pull-In</p><p>For a pipe lying on the seabed there are usually many equilibrium positions, since seabed friction will often be able</p><p>to hold the pipe in the shape it was originally laid. For pull-in analysis this originally-laid shape is generally known,</p><p>and the Prescribed method can be used to define this shape.</p><p>It is then optional whether Full Statics is included or not. Normally, it would not be included. If it is included then it</p><p>will have no effect if the Prescribed position is already in equilibrium – i.e. if friction is sufficient to hold the pipe in</p><p>that position. But if friction is not sufficient then Full Statics will tend to find a nearby position that is in equilibrium.</p><p>5.5.2 Buoy and Vessel Statics</p><p>Each buoy and vessel can be either included or excluded from the static analysis. This is controlled by the data item</p><p>Included in Static Analysis on the object's data form.</p><p>Notes: You can also use the Buoy Degrees of Freedom Included In Static Analysis data item, on the General</p><p>data form, to include or exclude all buoys with a single setting.</p><p>Also, for 6D Buoys, you can include just the translational degrees of freedom (X,Y,Z) and exclude the</p><p>rotational degrees of freedom. This is sometimes useful as an aid to convergence.</p><p>If a buoy is excluded from the static analysis, then when the static analysis is done OrcaFlex will simply place the</p><p>buoy in the Initial Position specified on the buoy data form. This will not, in general, be the equilibrium position. The</p><p>same applies to vessels.</p><p>If any buoys or vessels are included in the static analysis, then the static analysis finds the equilibrium position of</p><p>those buoys and vessels, using an iterative procedure.</p><p>This iterative procedure usually converges successfully, but in some cases there can be difficulties. To give the best</p><p>chance of convergence you should specify buoy and vessel initial positions that are good estimates of the true</p><p>equilibrium position. Often you can obtain good estimates by running static analyses of a simplified model and then</p><p>using the buoy positions found as the initial positions for the more complex model. There is a button on the general</p><p>data form for this purpose – see Use Calculated Positions.</p><p>Note: As an aid to static analysis, the out-of-balance forces on buoys and vessels can be drawn on the 3D</p><p>view.</p><p>If necessary, you can also control the buoy convergence process using the statics convergence parameters on the</p><p>general data form.</p><p>5.5.3 Vessel Multiple Statics</p><p>You can use the Multiple Statics command on the Calculation menu to perform a series of static analyses for a grid of</p><p>different positions of a vessel. This feature is mainly intended for use in mooring analyses.</p><p>The user specifies a series of regularly spaced positions for one vessel in the model and OrcaFlex then carries out</p><p>separate static analyses for each of these vessel positions. Key results, for example load-offset curves, are then made</p><p>available in the form of tables and graphs as a function of the offset distance.</p><p>The vessel positions are specified by a series of offsets about the vessel's initial position (see Vessel Multiple Statics</p><p>Data).</p><p>Note: If the offset vessel has "Included in Static Analysis" set to "Yes" then in Multiple Statics this setting</p><p>will be ignored (for the offset vessel only) and the vessel will be placed as specified by the offsets.</p><p>See Vessel Data.</p><p>If the static calculation fails to converge for a particular offset then this is noted in the Statics Progress Window and</p><p>the program continues to the next offset. No results are given for offsets with failed statics.</p><p>When the calculation is completed the program enters Multiple Statics Complete state. Results can only be viewed</p><p>in this state and are lost upon Reset. Results cannot be saved. A dynamic simulation cannot be carried out after</p><p>multiple statics – you must Reset first.</p><p>Theory, Dynamic Analysis w</p><p>132</p><p>5.6 DYNAMIC ANALYSIS</p><p>The dynamic analysis is a time simulation of the motions of the model over a specified period of time, starting from</p><p>the position derived by the static analysis.</p><p>The period of simulation is defined as a number of consecutive stages, whose durations are specified in the data.</p><p>Various controlling aspects of the model can be set on a stage by stage basis, for example the way winches are</p><p>controlled, the velocities and rates of turn of vessels and the releasing of lines, links and winches. This allows quite</p><p>complex operational sequences to be modelled.</p><p>Before the main simulation stage(s) there is a build-up stage, during which the wave and vessel motions are</p><p>smoothly ramped up from zero to their full size. Ramping of current is optional (see Current Data). This gives a</p><p>gentle start to the simulation and helps reduce the transients that are generated by the change from the static</p><p>position to full dynamic motion. This build-up stage is numbered 0 and its length should normally be set to at least</p><p>one wave period. The remaining stages, simply numbered 1, 2, 3, … are intended as the main stages of analysis.</p><p>Time is measured in OrcaFlex in</p><p>seconds. To allow you to time-shift one aspect of the model relative to the others,</p><p>different parts of the OrcaFlex model have their own user-specified time origins. See the diagram below.</p><p>For example, simulation time is measured relative to the simulation time origin, which is specified on the Wave page</p><p>on the environment data form. The simulation time origin is at the end of the build-up stage, so negative simulation</p><p>time is the build-up stage and the remaining stages are in positive simulation time. The figure below shows a</p><p>simulation using a build-up of 10 seconds, followed by two stages of 15 seconds each.</p><p>Each wave train also has its own time origin, and similarly for time-varying wind and any time history files that you</p><p>use. All of these time origins are defined relative to the global time origin (which is not user-specified), so if</p><p>necessary you can use the time origins to time-shift one aspect of the model relative to the others.</p><p>By default all of the time origins are zero, so all of the time frames coincide with global time. For most cases this</p><p>simple situation is all you need, but here is an example where you might want to adjust a time origin.</p><p> You might want to arrange that a wave crest, or a particularly large wave in a random sea, arrives at your vessel</p><p>at a particular point in the simulation. If you use the View Profile facility and find that the wave arrives at the</p><p>vessel at global time 2590s, then you can arrange that this occurs at simulation time 10s (i.e. 10 seconds into</p><p>stage 1) by either setting the simulation time origin to 2580 or else setting the wave train time origin to -2580.</p><p>The former shifts the simulation forwards to when the wave occurs, whereas the latter shifts the wave back to</p><p>the period the simulation covers.</p><p>w Theory, Dynamic Analysis</p><p>133</p><p>Simulation</p><p>Time</p><p>Origin</p><p>End of</p><p>Simulation</p><p>Stage 2Stage 1</p><p>Static Starting</p><p>Position</p><p>30-10 0 15</p><p>Simulation</p><p>Time t</p><p>Build-up</p><p>Global Time TT=0</p><p>Global</p><p>Time</p><p>Origin</p><p>Time-history</p><p>Time</p><p>Origin</p><p>Time-history Time</p><p>0</p><p>Wave Train Time</p><p>0</p><p>Wave Train</p><p>Time</p><p>Origin</p><p>Figure: Time and Simulation Stages</p><p>5.6.1 Calculation Method</p><p>OrcaFlex implements two complementary dynamic integration schemes, Explicit and Implicit, as described below.</p><p>Equation of motion</p><p>The equation of motion which OrcaFlex solves is as follows:</p><p>M(p,a) + C(p,v) + K(p) = F(p,v,t)</p><p>where</p><p>M(p,a) is the system inertia load.</p><p>C(p,v) is the system damping load.</p><p>K(p) is the system stiffness load.</p><p>F(p,v,t) is the external load.</p><p>p, v and a are the position, velocity and acceleration vectors respectively.</p><p>t is the simulation time.</p><p>Both schemes recompute the system geometry at every time step and so the simulation takes full account of all</p><p>geometric non-linearities, including the spatial variation of both wave loads and contact loads.</p><p>Explicit integration scheme</p><p>The explicit scheme is forward Euler with a constant time step. At the start of the time simulation, the initial</p><p>positions and orientations of all objects in the model, including all nodes in all lines, are known from the static</p><p>analysis. The forces and moments acting on each free body and node are then calculated. Forces and moments</p><p>considered include:</p><p> weight</p><p> buoyancy</p><p> hydrodynamic and aerodynamic drag</p><p>Theory, Dynamic Analysis w</p><p>134</p><p> hydrodynamic added mass effects, calculated using the usual extended form of Morison's Equation with user-</p><p>defined coefficients</p><p> tension and shear</p><p> bending and torque</p><p> seabed reaction and friction</p><p> contact forces with other objects</p><p> forces applied by links and winches</p><p>The equation of motion (Newton's law) is then formed for each free body and each line node:</p><p>M(p)a = F(p,v,t) - C(p,v) - K(p)</p><p>This is not the system-wide equation of motion described above, but a local equation of motion for each free body</p><p>and each line node. This means that solving these equations of motion merely requires the inversion of 3 by 3 or 6</p><p>by 6 mass matrices.</p><p>This equation is solved for the acceleration vector at the beginning of the time step, for each free body and each line</p><p>node, and then integrated using forward Euler integration. Let us denote the position, velocity and acceleration at</p><p>time step t by pt, vt and at respectively. Then the values at the end of the time step, at time t+1, are given by:</p><p>vt+1 = vt + dt.at</p><p>pt+1 = pt + dt.vt+1</p><p>where dt is the time step.</p><p>At the end of each time step, the positions and orientations of all nodes and free bodies are again known and the</p><p>process is repeated.</p><p>The time step required for stable integration is typically very short and OrcaFlex gives guidance on an appropriate</p><p>time step. Hydrodynamic and aerodynamic forces typically change little over such a short time interval, and are</p><p>time-consuming to compute. To save computing time, these loads are updated only over a longer outer time step.</p><p>Both time steps are user-defined and may be set equal for critical cases.</p><p>Of the various objects available in OrcaFlex, Lines are the most computationally demanding. For most models that</p><p>include lines, the length of time required for dynamic analysis is approximately proportional to the total number of</p><p>nodes used multiplied by the total number of inner time steps in the whole simulation. If the time step is maintained</p><p>at the recommended value and nodes are distributed uniformly along the lines, then the run time is approximately</p><p>proportional to the square of the number of nodes.</p><p>Finite element models may contain spurious high frequency response, a feature inherent in the finite element</p><p>method. The Line Target Damping data can be used to damp out this high frequency noise.</p><p>Implicit integration scheme</p><p>For implicit integration OrcaFlex uses the Generalised-α integration scheme as described by Chung and Hulbert.</p><p>The forces, moments, damping, mass etc. are calculated in the same way as for the explicit scheme. Then the system</p><p>equation of motion is solved at the end of the time step.</p><p>Because p, v and a are unknown at the end of the time step an iterative solution method is required. Consequently</p><p>each implicit time step consumes significantly more computation time than an explicit time step. However, the</p><p>implicit scheme is typically stable for much longer time steps than the explicit scheme and often this means that the</p><p>implicit scheme is faster.</p><p>Numerical damping of the integration scheme</p><p>Finite element models may contain spurious high frequency response, a feature inherent in the finite element</p><p>method. The Generalised-α integration scheme has controllable numerical damping which is desirable since it</p><p>removes this spurious, non-physical high frequency response. This numerical damping also leads to much more</p><p>stable convergence and hence allows for longer time steps and much faster simulations.</p><p>Any integration scheme which includes numerical damping of high frequency response must be careful to avoid</p><p>damping response at lower frequencies. The Generalised-α integration scheme is designed to minimise the low</p><p>frequency damping.</p><p>w Theory, Friction Theory</p><p>135</p><p>The numerical damping is determined by specifying the level of high frequency dissipation, ρ∞. OrcaFlex uses a</p><p>built-in value of 0.4 which has been chosen to give fast simulation run times without compromising accuracy.</p><p>5.6.2 Ramping</p><p>Simulation time is reduced by the use of a build up time at the beginning of the simulation. During the build-up time</p><p>the wave dynamics, vessel motions and optionally the current are built up smoothly from zero to their full level. This</p><p>gives a gentle start to the simulation which reduces transient responses and avoids the need for long simulation</p><p>runs. The build-up stage should normally be set to at least one wave period. Negative time is shown during the</p><p>simulation to indicate the build-up time; so time before time zero is build up time, time after time zero is normal</p><p>simulation with the full specified excitation.</p><p>When using a time</p><p>domain VIV model, ramping is also used to smooth the handover from the standard Morison drag</p><p>force applied in statics to the force given by the VIV model.</p><p>The ramping factor is calculated as follows:</p><p>Ramping Factor = r3 (6r2 -15r + 10)</p><p>where r is the proportion of the build-up stage completed, given by:</p><p>r = (Time + Length of Stage 0) / (Length of Stage 0)</p><p>Note: Time is negative throughout the build-up stage.</p><p>0</p><p>0.1</p><p>0.2</p><p>0.3</p><p>0.4</p><p>0.5</p><p>0.6</p><p>0.7</p><p>0.8</p><p>0.9</p><p>1</p><p>0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1</p><p>r</p><p>R</p><p>a</p><p>m</p><p>p</p><p>in</p><p>g</p><p>F</p><p>a</p><p>c</p><p>to</p><p>r</p><p>Figure: The OrcaFlex ramping function</p><p>This particular ramping function has been chosen so that its first and second derivatives are zero at the beginning</p><p>and end of the build-up stage.</p><p>5.7 FRICTION THEORY</p><p>OrcaFlex provides a simple friction model that can give an approximate representation of contact friction. This is</p><p>commonly used to model seabed friction, friction on mid-water arches, guide tube friction etc.</p><p>Seabed friction</p><p>In reality seabed interaction is much more complicated than simple friction – it involves effects such as the soil</p><p>being displaced by the line as it moves, accumulation of soil in front of the line, etc. To model seabed interaction</p><p>accurately would require much more information about the soil structure and would involve modelling the soil itself</p><p>which is beyond the scope of OrcaFlex.</p><p>Theory, Friction Theory w</p><p>136</p><p>Overview of the OrcaFlex friction model</p><p>OrcaFlex models friction for contact with the seabed or elastic solids. Hereafter we use the term solid to refer to</p><p>either the seabed or elastic solids. The objects which can contact with solids are Lines, 3D Buoys and 6D Buoys.</p><p>Note: Friction for contact with elastic solids is only included during dynamics.</p><p>Friction is modelled as Coulomb friction in the solid plane. Every object which is in contact with a solid keeps track</p><p>of a friction target position (discussed below) and a friction force is applied at which acts towards this target</p><p>position.</p><p>The standard Coulomb friction model states that a friction force of μR is applied, where μ is the friction coefficient</p><p>and R is the contact reaction force. However, this model results in a discontinuous Force / Deflection relationship</p><p>which would be impossible for a program like OrcaFlex to solve. Instead we use a modified Coulomb model as</p><p>illustrated below:</p><p>Deflection</p><p>Force</p><p>R</p><p>R</p><p>-Dcrit</p><p>R</p><p>Deflection</p><p>Force</p><p>R</p><p>+Dcrit</p><p>Figure: Standard Coulomb and modified Coulomb friction models</p><p>In the modified Coulomb friction model the transition from a friction force of -μR to +μR takes place as a linear</p><p>variation over the deflection range -Dcrit to +Dcrit. Here Dcrit is given by:</p><p>Dcrit = μR / (KsA)</p><p>where</p><p>Ks is the shear stiffness data item.</p><p>A is the contact area.</p><p>The friction force can be thought of as being ramped from 0 to a maximum value of μR as the deflection increases.</p><p>Higher values of Ks lead to the ramping taking place over a shorter distance, and vice versa.</p><p>Calculation of friction coefficient</p><p>The friction coefficient μ is defined as follows:</p><p> For contact between Lines and the seabed the friction coefficient is defined on the Line Type data.</p><p> For contact between 3D Buoys and the seabed the friction coefficient is defined on the 3D Buoy data.</p><p> For contact between 6D Buoys and the seabed the friction coefficient is defined on the 6D Buoy data.</p><p> For contact between Lines, 3D Buoys and 6D Buoys and elastic solids the friction coefficient is defined on the</p><p>Solid Friction Coefficients data form.</p><p>For line friction, both normal and axial coefficients can be defined. If these values are different, OrcaFlex uses a</p><p>single value of μ defined as:</p><p>w Theory, Friction Theory</p><p>137</p><p>μ = magnitude of the vector μnDn + μaDa</p><p>where</p><p>D = unit vector in the plane of the solid, from the node towards the target position.</p><p>Dn, Da = the vector components of D in the node's normal and axial directions.</p><p>Target positions in statics</p><p>Friction is only applied in statics for contact between lines and the seabed.</p><p>If the Step 1 Statics Method is Prescribed then the target positions are laid out along the prescribed shape.</p><p>For all other Step 1 Statics Methods the target positions are laid along the seabed in the direction specified by the</p><p>Lay Azimuth direction.</p><p>The distance between each target position is determined by the unstretched segment length and the As Laid</p><p>Tension. If each node was to sit at its target position then the effective tension throughout the line would be the As</p><p>Laid Tension.</p><p>Target positions in dynamics</p><p>During dynamics, at the end of each time step, each friction target position is updated using the following rules:</p><p> At the start of the dynamic simulation, for lines in contact with the seabed, the target position from statics is</p><p>used. Otherwise the target position is set equal to the contact position.</p><p> If an object is not in contact then the target position is not defined since no friction is applied.</p><p> If an object has just come into contact then the target position is set equal to the contact position.</p><p> If the target position is a distance greater than Dcrit from the contact position then the target position is placed at</p><p>a distance exactly Dcrit from the contact position on the vector D, as shown in the following figure. This can be</p><p>thought of as 'dragging' the target position towards the contact position.</p><p> Otherwise the target position is not modified.</p><p>Contact position</p><p>position</p><p>Vector D</p><p>Old Target position</p><p>Circle of</p><p>radius Dcrit</p><p>New Target position</p><p>Figure: Updating friction target positions during dynamics</p><p>Moments induced by friction (Lines)</p><p>The friction force is applied at the point of contact with the solid.</p><p>For lines this is at the line outer edge as defined by the contact diameter. Moments in OrcaFlex are reported at the</p><p>centreline and so the moment arm effect of applying the friction force at the outer edge results in a moment being</p><p>applied to the node. The applied moment is given by the vector cross-product p×F, where p is the point of contact</p><p>relative to the node origin and F is the applied friction force.</p><p>This frictional moment effect can most easily be visualised by considering a pipe being dragged laterally across a</p><p>surface with friction. It is intuitively obvious that the friction force will result in the pipe being twisted.</p><p>Note: This effect is only modelled if torsion is included in the model.</p><p>Theory, Spectral Response Analysis w</p><p>138</p><p>Moments induced by friction (3D and 6D Buoys)</p><p>Since 3D Buoys do not have rotational degrees of freedom, no such moments are applied.</p><p>For 6D Buoys the friction force is applied at each vertex in contact with the solid. If the vertex if offset from the buoy</p><p>origin then the appropriate moment, about the buoy origin, will be generated.</p><p>Shear damping</p><p>Objects moving in the solid plane may also experience a damping force. Let d be the distance between the contact</p><p>position and the target position. If 0 ≤ d ≤ Dcrit then a damping force in the solid plane is applied to the object with</p><p>magnitude given by:</p><p>D = S.min(2λ(MKA)½Vs, μR)</p><p>where</p><p>S is a scaling factor given by 1 - (d/Dcrit),</p><p>λ is percentage of critical contact damping / 100,</p><p>M is the mass of the object,</p><p>K is the solid normal stiffness,</p><p>A is the contact area,</p><p>Vs is the component of velocity in the solid plane.</p><p>5.8 SPECTRAL RESPONSE ANALYSIS</p><p>The Spectral Response Analysis capability of OrcaFlex provides a facility for determining the response</p><p>characteristics for any OrcaFlex results variable. This feature produces output similar to a frequency domain</p><p>package but the calculation is based on a random wave time domain simulation. The results of this simulation are</p><p>transformed into the frequency domain using a Fast Fourier Transform (FFT) and the spectral response is then</p><p>derived. The final output of the analysis is an RAO for the results</p><p>variable of interest.</p><p>Time domain random wave for spectral response analysis</p><p>In order to calculate spectral response you must first perform a random wave time domain simulation of the system</p><p>of interest. To do this you must specify a single wave train with wave type of Response Calculation. The random</p><p>wave used has a truncated white noise spectrum, which has the energy spread evenly over a user-specified range of</p><p>frequencies.</p><p>Spectral response calculation details</p><p>The spectral response analysis starts from the time history of some results variable of interest. The time history</p><p>covers the response calculation simulation period as specified on the General Data form. The duration of this period</p><p>together with the logging interval, t, determine the total number of samples available for the FFT.</p><p>OrcaFlex does not necessarily use all the available samples. This is because the FFT calculation is slow when</p><p>presented with a time history whose size is a large prime, or is a product of large primes.</p><p>Suppose that N is the total number of available samples. OrcaFlex will choose M with the properties that that M ≤ N</p><p>and the FFT can be calculated quickly and efficiently for M samples. Having chosen M, OrcaFlex then selects the M</p><p>samples from the original time history that are closest to the end of the simulation.</p><p>OrcaFlex then calculates the power spectral density (PSD) of these M time history samples using the FFT. The PSD is</p><p>denoted as the sequence (fi, Pi) for i = 1, 2, …, M/2 where Pi is understood to be the PSD for frequency fi. The values</p><p>of fi are integer multiples of the FFT's fundamental frequency, Δf = 1/(tM), given by fi = iΔf. The maximum frequency</p><p>equals (M/2)Δf = 1/(2t). This frequency is known as the Nyquist critical frequency.</p><p>The RAO is calculated as</p><p>Ri = (Pi/Si)½, for i = 1, 2, …, M/2</p><p>where Ri is the RAO at frequency fi and Si is the spectral density at frequency fi for the response calculation random</p><p>wave.</p><p>Notes: Provided that a Response Calculation wave type has been selected the Waves page of the</p><p>Environment data form reports the value of M. This takes the form of a text label which says "The</p><p>response calculation will use M data points".</p><p>w Theory, Extreme Value Statistics Theory</p><p>139</p><p>Only the frequencies which lie in the target frequency range are used for wave components.</p><p>Because of this there may be fewer than M/2 wave components.</p><p>Spectral response random wave components</p><p>It is important that the random wave components have frequencies which match those produced by the FFT. This is</p><p>because of a phenomenon of the FFT known as frequency leakage which would occur if the random wave</p><p>component frequencies did not match the FFT frequencies. The effect of leakage is to make the output of the FFT</p><p>noisy.</p><p>The response calculation wave components are selected with frequencies that are also integer multiples of Δf. In this</p><p>way the frequency leakage effect is avoided.</p><p>Not all these frequencies are used in the response calculation random wave. This is because there could potentially</p><p>be so many frequencies (i.e. for large values of M/2) that the real-time required to simulate a wave with that many</p><p>components would be prohibitive. The user controls the range of frequencies to be used with the Target Frequency</p><p>Range data on the Environment data form.</p><p>Comparison with traditional frequency domain methods</p><p>For frequency domain approaches to calculating system responses each non-linearity in the system has to be</p><p>handled in special ways. However, by calculating the RAOs using a fully non-linear time domain simulation and then</p><p>transforming to the frequency domain using Fourier transform methods, the non-linearities are included in the</p><p>calculation automatically.</p><p>The advantage of the method used by OrcaFlex is that non-linearities can be handled implicitly without the need for</p><p>special, bespoke linearisation techniques.</p><p>5.9 EXTREME VALUE STATISTICS THEORY</p><p>The theory for the calculation of the extreme value statistics results provided by OrcaFlex depends on which</p><p>extreme value statistics distribution is chosen:</p><p> The Rayleigh distribution method uses a direct calculation, based on the spectral moments of all the data.</p><p> The Weibull and Generalised Pareto (GPD) distributions are fitted to selected extremes of the data, with the</p><p>extremes being selected using the peaks-over-threshold method, with declustering to reduce dependence</p><p>between the selected extremes. The Weibull or GPD distribution is then fitted to those extremes using the</p><p>maximum likelihood method.</p><p>Rayleigh Distribution</p><p>The derivation and use of spectral moments to fit the Rayleigh distribution is described in detail by Ochi (he calls it</p><p>the "exact method"). For the Rayleigh distribution to be appropriate for the peak responses, the response variable</p><p>must be a stationary Gaussian process.</p><p>Ochi shows that, under the Gaussian assumption, the most probable maximum value occurring in storm duration T is</p><p>given by</p><p>μ + σ[2ln(n)]½</p><p>where n = T/Tz is the number of peaks and μ, σ and Tz are the mean, standard deviation and mean up-crossing</p><p>period, respectively, of the time history being analysed. OrcaFlex reports this most probable extreme value for the</p><p>specified storm duration.</p><p>Ochi goes on to show that, for low values of risk parameter α, the extreme value which will be exceeded only with</p><p>probability α is</p><p>μ + σ[2ln(n/α)]½</p><p>However this latter formula is approximate and is valid only for low values of α. So OrcaFlex instead calculates the</p><p>extreme value which will be exceeded with probability α using the alternative formula</p><p>μ + σ[2ln(-n/ln{1-α})]½</p><p>Ochi derives this formula using Cramér's approximation method in his paper On Prediction of Extreme Values, and it</p><p>gives good results over the whole range of values of risk factor α.</p><p>Note that all the above formulae are for maxima, i.e. analysing the upper tail extremes. Corresponding formulae for</p><p>minima (lower tail) are trivially obtained by replacing the plus signs with minus signs in these formulae.</p><p>Theory, Extreme Value Statistics Theory w</p><p>140</p><p>Weibull and Generalised Pareto Distributions</p><p>The Weibull and Generalised Pareto (GPD) distributions are both fitted using the maximum likelihood method. Both</p><p>distributions are fitted to extremes of the data that are selected using the peaks-over-threshold method with</p><p>(optional) declustering. They differ only in the actual statistical distribution that is fitted and then used to predict</p><p>the extreme values.</p><p>Maximum likelihood</p><p>Maximum likelihood estimation is a standard general-purpose statistical technique for fitting a given parametric</p><p>distribution to an arbitrary set of data. It fits the parameters of the distribution to the data by calculating the</p><p>parameters that make the observed data most likely under the chosen distribution. The technique is widely</p><p>described in statistical texts; in particular the book by Coles is particularly relevant, since he describes (Section</p><p>4.3.2, Parameter Estimation) its application to the GPD. Coles also documents the motivation for, and</p><p>implementation of, the peaks-over-threshold method (Chapter 4, Threshold Models) and declustering (5.3, Modelling</p><p>Stationary Series).</p><p>Threshold models</p><p>When the object of primary interest is extrapolation into the tails of the data, it is safest to use a model that is fitted</p><p>only to the tails of the data. This is because models that are fitted to the entire dataset tend to be driven by features</p><p>in the body of the data, which may not be relevant to the tail behaviour. Mathematical theory (e.g. Coles, Theorem</p><p>4.1) tells us that as the size of the dataset and the threshold for fitting increase, the peaks over the threshold</p><p>converge in distribution to a Generalised Pareto distribution.</p><p>Declustering</p><p>An important assumption underpinning the maximum likelihood method is that the data are independent. However,</p><p>this is often not the case. Consider daily temperature for example,</p><p>where one cold day is likely to be followed by</p><p>another: successive daily values are not independent, but values a week or a month apart might well be considered</p><p>independent. For OrcaFlex time history results this is even more important, since unless the log interval is</p><p>extremely long, then successive time history values will certainly not be independent.</p><p>We can get much closer to independence by sub-sampling the data, ensuring that the points we choose are</p><p>sufficiently far apart as to be approximately independent. The usual way to do this is declustering: OrcaFlex uses</p><p>either runs declustering as illustrated by Coles (5.3.3, Wooster Temperature Series), or defines a cluster to be the set</p><p>of values between successive up-crossings of the mean value.</p><p>The complete model-fitting process is then summarised as:</p><p>1. Use declustering to identify clusters of exceedences.</p><p>2. Determine the maximum excess within each cluster.</p><p>3. Assuming independence between these maxima, use maximum likelihood to fit the chosen distribution to them.</p><p>Weibull distribution</p><p>OrcaFlex fits the two-parameter Weibull distribution with distribution function</p><p>FW2(y) = 1 - exp{(-y/σ)ξ}</p><p>to the declustered excesses over threshold, y, where</p><p>σ = Weibull distribution scale parameter</p><p>ξ = Weibull distribution shape parameter.</p><p>This is equivalent to applying the three-parameter Weibull distribution</p><p>FW3(x) = 1 - exp[{-(x-μ)/σ}ξ]</p><p>to the original values x unadjusted for the threshold (i.e. x=μ+y), where the location parameter μ is the user-</p><p>specified threshold value and is not fitted by the maximum likelihood calculation.</p><p>Generalized Pareto distribution</p><p>The Generalized Pareto distribution function, for the excesses y above threshold, is</p><p>FGPD(y) = 1 - (1+ξy/σ)+</p><p>-1/ξ for ξ≠0, where (1+ξy/σ)+ = max(0, 1+ξy/σ)</p><p>FGPD(y) = 1 - exp(-y/σ) for ξ=0</p><p>w Theory, Environment Theory</p><p>141</p><p>where</p><p>σ = GPD scale parameter</p><p>ξ = GPD shape parameter.</p><p>5.10 ENVIRONMENT THEORY</p><p>5.10.1 Buoyancy Variation with Depth</p><p>The buoyancy of an object is normally assumed to be constant and not vary significantly with position. The</p><p>buoyancy is equal to ρVg, where ρ is the water density, V is the volume and g is the acceleration due to gravity. In</p><p>reality the buoyancy does vary due to the following effects:</p><p> If the object is compressible then its volume V will reduce with depth due to the increasing pressure.</p><p> The water density ρ can vary with position, either because of the compressibility of the water, or else because of</p><p>temperature or salinity variations. Normally the density increases with depth, since otherwise the water column</p><p>would be unstable (the lower density water below would rise up through the higher density water above).</p><p>For buoys and lines these effects can be modelled in OrcaFlex.</p><p>Note: The bulk modulus and density variation facilities in OrcaFlex only affect the buoyancy of objects.</p><p>OrcaFlex does not allow for compressibility or density variation when calculating hydrodynamic</p><p>effects such as drag, added mass, etc. The calculation of hydrodynamic effects use the</p><p>uncompressed volume and a nominal sea density value, which is taken to be the density value at</p><p>the sea density origin.</p><p>Compressibility of Buoys and Lines</p><p>All things are compressible to some extent. The effect is usually not significant, but in some cases it can have a</p><p>significant effect on the object's buoyancy. To allow these effects to be modelled, you can specify the compressibility</p><p>of a 3D Buoy, 6D Buoy or Line Type by giving the following data on the object's data form.</p><p>Bulk Modulus</p><p>The bulk modulus, B, specifies how the object's volume changes with pressure. If we denote by V the compressed</p><p>volume of the object then V is given by:</p><p>V = V0(1-P/B)</p><p>where V0 is the uncompressed volume at atmospheric pressure, and P is the pressure excess over atmospheric</p><p>pressure.</p><p>The bulk modulus has the same units as pressure F/L2 and the above formula can be thought of as saying that the</p><p>volume reduces linearly with pressure, and at a rate that would see the object shrink to zero volume if the pressure</p><p>ever reached B. For an incompressible object the bulk modulus is infinity, and this is the default value in OrcaFlex.</p><p>The above formula breaks down when P>B. In this case OrcaFlex uses a compressed volume V of zero. However, the</p><p>relationship between pressure and volume would become inaccurate well before the pressure exceeded the bulk</p><p>modulus. In practise B is normally very large, so the object normally only experiences pressures that are small</p><p>compared to B.</p><p>5.10.2 Current Theory</p><p>Extrapolation</p><p>In the presence of waves, the current must be extrapolated above the still water level; in OrcaFlex we adopt the</p><p>convention that the surface current applies to all levels above the still water level.</p><p>If a sloping seabed is specified, the boundary is inconsistent with a horizontal current. This effect is not usually</p><p>important and is uncorrected in OrcaFlex. The current at the greatest depth specified is applied to all greater depths.</p><p>Interpolated Method</p><p>Horizontal current is specified as a full 3D profile, variable in magnitude and direction with depth. The profile</p><p>should be specified from the still water surface to the seabed. Linear interpolation is used for intermediate depths. If</p><p>the specified profile does not cover the full depth then it is extrapolated (see Extrapolation above).</p><p>Theory, Environment Theory w</p><p>142</p><p>Power Law Method</p><p>Current direction is specified and does not vary with depth. Speed (S) varies with position (X,Y,Z) according to the</p><p>formula:</p><p>S = Sseabed + (Ssurface - Sseabed) x ((Z-Zseabed) / (Zsurface-Zseabed)) ^ (1/Exponent)</p><p>where</p><p>Ssurface and Sseabed are the current speeds at the surface and seabed,</p><p>Exponent is the power law exponent,</p><p>Zsurface is the water surface Z level,</p><p>Zseabed is the Z level of the seabed directly below (X,Y).</p><p>Note: If Z is below the seabed (e.g. has penetrated the seabed) then the current speed is set to Sseabed</p><p>and if Z is above the surface (e.g. in a wave crest) then current speed is set to Ssurface.</p><p>5.10.3 Seabed Theory</p><p>The seabed reaction force is the sum of a penetration resistance force in the seabed normal direction and a friction</p><p>force in the direction tangential to the seabed plane and towards the friction target position. If explicit integration is</p><p>used in the dynamic analysis then, in addition, seabed damping forces are applied in the normal and tangential</p><p>directions.</p><p>The penetration resistance force depends on the choice of seabed model used – for details see either Linear Seabed</p><p>Model Theory or Non-linear Soil Model Theory. For details of the friction force see Friction Theory.</p><p>Objects Affected</p><p>3D buoys and 6D buoys, lines and drag chains interact with the seabed. Other objects are not affected by it.</p><p>A line interacts when one of its nodes penetrates the seabed. The seabed reaction forces are calculated using the</p><p>penetration of the lower outer surface of the line (based on the line type contact diameter) and the seabed forces are</p><p>applied at that point. The seabed lateral friction force is calculated using the line type seabed friction coefficient.</p><p>A 3D buoy interacts when the buoy origin penetrates the seabed. The seabed reaction forces are calculated using the</p><p>penetration of the buoy origin, and are applied at the buoy origin. The seabed friction force is calculated using the</p><p>buoy seabed friction coefficient.</p><p>A 6D buoy interacts when any of its vertices penetrates the seabed. Each penetrating vertex experiences its own</p><p>seabed normal reaction and lateral friction force, based on the penetration of that vertex and displacement of that</p><p>vertex from its friction target position, and the forces are applied at that vertex. This gives a model where each</p><p>vertex behaves rather like a pad (such as the landing pad on a lunar module).</p><p>Drag chain interaction with the seabed is calculated differently – see drag chain seabed interaction.</p><p>Linear Seabed Model Theory</p><p>In the Linear seabed model the seabed behaves as a linear spring in the normal direction, with spring strength</p><p>equal to the Normal seabed stiffness specified in the seabed data.</p><p>Normal Seabed Stiffness Force</p><p>The normal stiffness reaction force has magnitude = KnAd and is applied in the outwards normal direction, where:</p><p>Kn = seabed normal stiffness</p><p>A = penetrator contact area</p><p>d = depth of penetration into the seabed.</p><p>For details on how the penetrator contact area is calculated see 3D Buoy Theory, 6D Buoy Theory and Line</p><p>Interaction with Seabed and Solids.</p><p>Normal Seabed Damping Force</p><p>If implicit integration is used in the dynamic analysis then no seabed damping forces are applied. If explicit</p><p>integration is used in the dynamic analysis then, seabed damping forces are applied in the normal and tangential</p><p>directions, as follows.</p><p>Content/html/Friction_Theory.htm</p><p>w Theory, Environment Theory</p><p>143</p><p>The normal seabed damping force is only applied when the penetrating object is travelling into the seabed, not when</p><p>it is coming out of the seabed. It is applied in the seabed outward normal direction and has magnitude Dn given by:</p><p>Dn = λ.2(MKnA)½Vn if Vn > 0</p><p>Dn = 0 if Vn ≤ 0</p><p>where</p><p>λ = seabed percent critical damping / 100</p><p>M = mass of the object (e.g. the mass of a node of a line)</p><p>Kn = seabed normal stiffness</p><p>A = penetrator contact area</p><p>Vn = component of velocity normal to the seabed, positive when travelling into the seabed and negative when</p><p>coming out.</p><p>The tangential seabed damping force, Dt, is applied in the direction opposing the tangential component of the</p><p>velocity of the penetrator. It is given by</p><p>Dt = -λ2(MKtA)½Vt</p><p>where</p><p>Kt = seabed shear stiffness</p><p>Vt = vector component of penetrator velocity tangential to the seabed.</p><p>For details on how the penetrator contact area is calculated see 3D Buoy Theory, 6D Buoy Theory and Line</p><p>Interaction with Seabed and Solids.</p><p>5.10.4 Seabed Non-Linear Soil Model Theory</p><p>The non-linear soil model has been developed in collaboration with Prof. Mark Randolph FRS (Centre for Offshore</p><p>Foundation Systems, University of Western Australia). It is a development from earlier models that proposed and</p><p>used a hyperbolic secant stiffness formulation, such as those proposed by Bridge et al and Aubeny et al.</p><p>For details of the data used by the non-linear soil model and its suitability for different seabed types see Non-linear</p><p>Soil Model.</p><p>Note: The non-linear soil model is currently experimental and we are working on comparing the model</p><p>against experimental results for pipe-seabed contact. Please contact Orcina if you have any</p><p>feedback and comments on the model or ideas for improvement.</p><p>Full details of the non-linear soil model are given in Randolph and Quiggin (2009). The main aspects of the model</p><p>are:</p><p> It models the seabed normal resistance using four penetration modes, as shown in the diagram below.</p><p> In each penetration mode the seabed reaction force per unit length, P(z), is modelled using an analytic function</p><p>of the non-dimensionalised penetration z/D, where z = penetration and D = penetrator contact diameter. See</p><p>Penetration Resistance Formulae below.</p><p> In Not In Contact mode the resistance P(z) is zero. In the other 3 modes the formula for P(z) uses a term of</p><p>hyperbolic form, which provides a high stiffness response for small reversals of motion, but ensures that as the</p><p>penetration z increases or decreases from its value when this episode of penetration or uplift started, then the</p><p>resistance P(z) asymptotically approaches the soil ultimate penetration resistance (for penetration) or ultimate</p><p>suction resistance (for uplift) at that penetration depth.</p><p>These features are now described in more detail in the sections below.</p><p>http://www.cofs.uwa.edu.au/</p><p>http://www.cofs.uwa.edu.au/</p><p>Theory, Environment Theory w</p><p>144</p><p>Penetration Modes</p><p>Uplift</p><p>Initial</p><p>Penetration</p><p>Repenetration</p><p>Not in Contact</p><p>First</p><p>contact</p><p>only Start of</p><p>first uplift</p><p>only</p><p>Second or</p><p>subsequent</p><p>contact</p><p>Start</p><p>repenetrating</p><p>when still in</p><p>contact</p><p>Start of second</p><p>or subsequent</p><p>uplift</p><p>Break</p><p>contact</p><p>Figure: Soil Model Penetration Modes</p><p>The penetration mode of a given penetrator (e.g. a node on a line, a vertex of a 6D buoy or the origin of a 3D buoy) is</p><p>determined by its penetration, z, and in the dynamic analysis by whether the penetration has increased or</p><p>decreased since the previous time step. The details are as follows.</p><p> In the static analysis the Uplift and Repenetration modes are not used and the penetration mode is set to</p><p>Initial Penetration if the penetration is +ve or to Not In Contact otherwise. The effect of this is that the static</p><p>position found is based on the assumption that any static penetration occurred as a single progressive</p><p>penetration, and it does not allow for the effect any of uplift and repenetration that might have occurred during</p><p>first installation. OrcaFlex cannot allow for such effects since it only has limited information about how the line</p><p>was originally laid.</p><p> The dynamic simulation starts from the results of the static analysis, so the penetrator starts the simulation in</p><p>either Not In Contact mode or Initial Penetration mode. If it starts in Not In Contact mode then it changes to</p><p>Initial Penetration mode the first time the penetration becomes +ve.</p><p> Once initial penetration has occurred in the dynamic simulation, the penetrator then stays in Initial</p><p>Penetration mode until it starts to lift up, and it then changes to Uplift mode.</p><p> The penetrator then stays in Uplift mode until either the penetration falls to zero, in which case it breaks</p><p>contact and changes to Not In Contact mode, or else until the penetration starts to increase again, in which case</p><p>it changes to Repenetration mode. Similarly, Repenetration mode persists until the penetrator starts to lift up</p><p>again, when it changes to Uplift mode. So if the penetrator stays in contact with the seabed but oscillates up and</p><p>down then it switches back and forth between Uplift and Repenetration modes.</p><p> If the penetrator breaks contact and then later makes contact again then it enters Repenetration mode, not</p><p>Initial Penetration mode. This is because the model assumes that second and subsequent periods of contact</p><p>are making contact with the same area of seabed as was previously disturbed by the initial penetration.</p><p>Ultimate Resistance Limits</p><p>The resistance formulae are arranged so that as penetration z increases (for penetration) or decreases (for uplift)</p><p>then the resistance asymptotically approaches the ultimate penetration resistance Pu(z) (for penetration) or the</p><p>ultimate suction resistance Pu-suc(z) (for uplift). These ultimate penetration and suction asymptotic limits are given</p><p>by</p><p>w Theory, Environment Theory</p><p>145</p><p>Pu(z) = Nc(z/D)su(z)D</p><p>Pu-suc(z) = -fsucPu(z)</p><p>where</p><p> su(z) = undrained shear strength at penetration z. This is given by su(z) = su0 + ρz, where su0 is the undrained</p><p>shear strength at the mudline and ρ is the undrained shear strength gradient, both of which are specified in the</p><p>Seabed Soil Properties data.</p><p> D = penetrator contact diameter. For 3D Buoys and 6D Buoys the contact diameter is taken to be the square root</p><p>of the contact area (see 3D Buoy contact area and 6D Buoy Theory). For Lines the contact diameter is as</p><p>specified in the Line Type Contact Data.</p><p> Nc(z/D) = bearing factor. For z/D ≥ 0.1 this is modelled using the power law formula Nc(z/D) = a(z/D)b, where a</p><p>and b are the non-dimensional Penetration Resistance Parameters of the model, as specified in the Soil Model</p><p>Parameters. For z/D < 0.1 the formula Nc = Nc(0.1)(10z/D)½ is used instead, which gives a good approximation</p><p>to the theoretical bearing factor for shallow penetration.</p><p> fsuc = non-dimensional Suction Resistance Ratio parameter of the model, as specified in the Soil Model</p><p>Parameters.</p><p>Penetration Resistance Formulae</p><p>In</p><p>T, 2004. Steel Catenary Riser Touchdown Point Vertical Interaction Models. OTC</p><p>16628, 2004.</p><p>Carter D J T, 1982. Prediction of Wave height and Period for a Constant Wind Velocity Using the JONSWAP Results,</p><p>Ocean Engineering, 9, no. 1, 17-33.</p><p>Casarella M J and Parsons M, 1970. Cable Systems Under Hydrodynamic Loading. Marine Technology Society Journal</p><p>4, No. 4, 27-44.</p><p>Chapman D A, 1984. Towed Cable Behaviour During Ship Turning Manoeuvres. Ocean Engineering. 11, No. 4.</p><p>Chung J and Hulbert G M, 1993. A time integration algorithm for structural dynamics with improved numerical</p><p>dissipation: The generalized-α method. ASME Journal of Applied Mechanics. 60, 371-375.</p><p>CMPT, 1998. Floating structures: A guide for design and analysis. Edited by Barltrop N D P. Centre for Marine and</p><p>Petroleum Technology publication 101/98, Oilfield Publications Limited.</p><p>Coles S, 2001. An Introduction to Statistical Modelling of Extreme Values. Springer.</p><p>Cummins W E, 1962. The impulse response function and ship motions. Schiffstechnik, 9, 101-109.</p><p>mailto:orcina@orcina.com</p><p>http://www.orcina.com/</p><p>http://www.orcina.com/ContactOrcina</p><p>http://www.mms.gov/tarprojects/510.htm</p><p>w Introduction, References and Links</p><p>17</p><p>Dean R G, 1965. Stream function representation of non-linear ocean waves. J. Geophys. Res., 70, 4561-4572.</p><p>Dirlik T, 1985. Application of computers in Fatigue Analysis. PhD Thesis University of Warwick.</p><p>DNV-OS-F201, Dynamic Risers.</p><p>DNV-RP-C205, Environmental Conditions and Environmental Loads.</p><p>DNV-RP-H103, Modelling and Analysis of Marine Operations, April 2011.</p><p>ESDU 71016. Fluid forces, pressures and moments on rectangular blocks. ESDU 71016 ESDU International, London.</p><p>ESDU 80025. Mean forces, pressures and flow field velocities for circular cylindrical structures: Single cylinder with</p><p>two-dimensional flow. ESDU 80025 ESDU International, London.</p><p>Falco M, Fossati F and Resta F, 1999. On the vortex induced vibration of submarine cables: Design optimization of</p><p>wrapped cables for controlling vibrations. 3rd International Symposium on Cable Dynamics, Trondheim, Norway.</p><p>Faltinsen O M, 1990. Sea loads on ships and offshore structures. Cambridge University Press.</p><p>Fenton J D, 1979. A high-order cnoidal wave theory. J. Fluid Mech. 94, 129-161.</p><p>Fenton J D, 1985. A fifth-order Stokes theory for steady waves. J. Waterway, Port, Coastal & Ocean Eng. ASCE. 111,</p><p>216-234.</p><p>Fenton J D, 1990. Non-linear wave theories. Chapter in "The Sea – Volume 9: Ocean Engineering Science", edited by</p><p>B. Le MeHaute and D. M. Hanes. Wiley: New York. 3-25.</p><p>Fenton J D, 1995. Personal communication – pre-print of chapter in forthcoming book on cnoidal wave theory.</p><p>Gregory R W and Paidoussis M P, 1996. Unstable oscillation of tubular cantilevers conveying fluid: Part 1:Theory.</p><p>Proc. R. Soc. 293 Series A, 512-527.</p><p>Hartnup G C, Airey R G and Fraser J M, 1987. Model Basin Testing of Flexible Marine Risers. OMAE Houston.</p><p>Hoerner S F 1965. Fluid Dynamic Drag, Published by the author at Hoerner Fluid Dynamics, NJ 08723, USA.</p><p>Huse E, 1993. Interaction in Deep-Sea Riser Arrays. OTC 7237, 1993.</p><p>Isherwood R M, 1987. A Revised Parameterisation of the JONSWAP Spectrum. Applied Ocean Research, 9, No. 1</p><p>(January), 47-50.</p><p>Iwan W D, 1981. The vortex-induced oscillation of non-uniform structural systems. Journal of Sound and Vibration,</p><p>79, 291-301.</p><p>Iwan W D and Blevins R D, 1974. A Model for Vortex Induced Oscillation of Structures. Journal of Applied Mechanics,</p><p>September 1974, 581-586.</p><p>Kotik J and Mangulis V, 1962. On the Kramers-Kronig relations for ship motions. Int. Shipbuilding Progress, 9, No. 97,</p><p>361-368.</p><p>Lamb H, 1932. Hydrodynamics. 6th Edition.Cambridge University Press.</p><p>Larsen C M, 1991. Flexible Riser Analysis – Comparison of Results from Computer Programs. Marine Structures,</p><p>Elsevier Applied Science.</p><p>Longuet-Higgins M S, 1983. On the joint distribution of wave periods and amplitudes in a random wave field.</p><p>Proceedings Royal Society London, Series A, Mathematical and Physical Sciences.389, 241-258.</p><p>Maddox S J, 1998. Fatigue strength of welded structures. Woodhead Publishing Ltd, ISBN 1 85573 013 8.</p><p>Malenica S et al, 1995. Wave and current forces on a vertical cylinder free to surge and sway. Applied Ocean</p><p>Research, 17, 79-90.</p><p>Molin B, 1994. Second-order hydrodynamics applied to moored structures. A state-of-the-art survey. Ship</p><p>Technology Research. 41, 59-84.</p><p>Morison J R, O'Brien M D, Johnson J W, and Schaaf S A, 1950. The force exerted by surface waves on piles. Petrol</p><p>Trans AIME. 189.</p><p>Mueller H F, 1968. Hydrodynamic forces and moments of streamlined bodies of revolution at large incidence.</p><p>Schiffstechnik. 15, 99-104.</p><p>Newman J N. 1974. Second-order, slowly-varying forces on vessels in irregular waves. Proc Int Symp Dynamics of</p><p>Marine Vehicles and Structures in Waves, Ed. Bishop RED and Price WG, Mech Eng Publications Ltd, London.</p><p>Introduction, References and Links w</p><p>18</p><p>Newman J N, 1977. Marine Hydrodynamics, MIT Press.</p><p>NDP, 1995. Regulations relating to loadbearing structures in the petroleum activities. Norwegian Petroleum</p><p>Directorate.</p><p>Ochi M K and Hubble E N, 1976. Six-parameter wave spectra, Proc 15th Coastal Engineering Conference, 301-328.</p><p>Ochi M K, 1973. On Prediction of Extreme Values, J. Ship Research, 17, No. 1, 29-37.</p><p>Ochi M K, 1998. Ocean Waves: The Stochastic Approach, Cambridge University Press.</p><p>Oil Companies International Marine Forum, 1994. Prediction of Wind and Current Loads on VLCCs, 2nd edition,</p><p>Witherby & Co., London.</p><p>Paidoussis M P, 1970. Dynamics of tubular cantilevers conveying fluid. J. Mechanical Engineering Science, 12, No 2,</p><p>85-103.</p><p>Paidoussis M P and Deksnis E B, 1970. Articulated models of cantilevers conveying fluid: The study of a paradox. J.</p><p>Mechanical Engineering Science, 12, No 4, 288-300.</p><p>Paidoussis M P and Lathier B E, 1976. Dynamics of Timoshenko beams conveying fluid. J. Mechanical Engineering</p><p>Science, 18, No 4, 210-220.</p><p>Palmer A C and Baldry J A S, 1974. Lateral buckling of axially constrained pipes. J. Petroleum Technology, Nov 1974,</p><p>1283-1284.</p><p>Pode L, 1951. Tables for Computing the Equilibrium Configuration of a Flexible Cable in a Uniform Stream . DTMB</p><p>Report. 687.</p><p>Principles of Naval Architecture. Revised edition, edited by J P Comstock, 1967. Society of Naval Architects and</p><p>Marine Engineers, New York.</p><p>Puech A, 1984. The Use of Anchors in Offshore Petroleum Operations. Editions Technique.</p><p>Randolph M and Quiggin P, 2009. Non-linear hysteretic seabed model for catenary pipeline contact. OMAE paper</p><p>79259, 2009 (www.orcina.com/Resources/Papers/OMAE2009-79259.pdf).</p><p>Rawson and Tupper, 1984. Basic Ship Theory 3rd ed, 2: Ship Dynamics and Design, 482. Longman Scientific &</p><p>Technical (Harlow).</p><p>Rienecker M M and Fenton J D, 1981. A Fourier approximation method for steady water waves. J. Fluid Mech. 104,</p><p>119-137.</p><p>Roark R J, 1965. Formulas for Stress and Strain. 4th edition McGraw-Hill.</p><p>Sarpkaya T, Shoaff R L, 1979. Inviscid Model of Two-Dimensional Vortex Shedding by a Circular Cylinder. Article No.</p><p>79-0281R, AIAA Journal,17, no. 11, 1193-1200.</p><p>Sarpkaya T, Shoaff R L, 1979. A discrete-vortex analysis of flow about stationary and transversely oscillating circular</p><p>cylinders. Report no. NPS-69SL79011, Naval Postgraduate School, Monterey, California.</p><p>Rychlik I, 1987. A new definition of the rainflow cycle counting method. Int. J. Fatigue 9, No 2, 119-121.</p><p>Skjelbreia L, Hendrickson J, 1961. Fifth order gravity wave theory. Proc. 7th Conf. Coastal Eng. 184-196.</p><p>Sobey R J, Goodwin P, Thieke R J and Westberg R J, 1987. Wave theories. J. Waterway, Port, Coastal & Ocean Eng.</p><p>ASCE 113, 565-587.</p><p>Sparks C P, 1980. Le comportement mecanique des risers influence des principaux parametres. Revue de l'Institut</p><p>Francais du Petrol, 35, no. 5, 811.</p><p>Sparks C P, 1984. The influence of tension, pressure and weight on pipe and riser deformations and stresses. J.</p><p>Energy Resources Technology,</p><p>Not In Contact mode the penetration resistance P(z) is zero.</p><p>In the other three modes the resistance P(z) is modelled using formulae that involve the following variables:</p><p> ζ = z / (D/Kmax). This is the penetration, but non-dimensionalised to be in units of D/Kmax, where Kmax is the</p><p>Normalised Maximum Stiffness parameter of the model, as specified in the Soil Model Parameters.</p><p> z0 = penetration z at which the latest episode of this contact mode started, i.e. the value at the time the latest</p><p>transition into this contact mode occurred.</p><p> ζ0 = z0 / (D/Kmax) = non-dimensionalised penetration at which the latest episode of this contact mode started.</p><p> P0 = resistance P(z) at which the latest episode of this contact mode started.</p><p>Initial Penetration Mode</p><p>For Initial Penetration mode the starting penetration and resistance values, z0 and P0, are both zero. The</p><p>penetration resistance is then given by</p><p>P(z) = HIP(ζ).Pu(z) (1)</p><p>where</p><p>HIP(ζ) = ζ / [1 + ζ]</p><p>The term HIP(ζ) is a hyperbolic factor that equals 0 when ζ = 0 when initial penetration starts, equals ½ when ζ = 1,</p><p>i.e. when z = D/Kmax, and asymptotically approaches 1 as penetration gets large compared to D/Kmax. The purpose of</p><p>this factor is to provide a high initial stiffness while ensuring that the penetration resistance P(z) rises smoothly</p><p>from zero when contact first starts (when ζ and z are both 0) and asymptotically approaches the ultimate</p><p>penetration resistance, Pu(z), if ζ gets large (i.e. if z gets large compared to D/Kmax). This is illustrated by the blue</p><p>curve in the model characteristics diagram below, which approaches the ultimate penetration resistance limit</p><p>(upper grey curve) as penetration gets large compared to D/Kmax.</p><p>Uplift Mode</p><p>For Uplift mode the penetration resistance is given by</p><p>P(z) = P0 - HUL(ζ0 - ζ)(P0 - Pu-suc(z)) (2a)</p><p>but subject to a suction limit – see below. Here:</p><p> HUL(ζ0 - ζ) = ( ζ0 - ζ ) / [ AUL(z) + (ζ0 - ζ) ]</p><p> AUL(z) = [P0 - Pu-suc(z)] / Pu(z0)</p><p>The term HUL(ζ0 - ζ) is a hyperbolic factor that equals 0 when ζ = ζ0 at the start of this uplift, and asymptotically</p><p>approaches 1 if the non-dimensional uplift (ζ0 - ζ) gets large compared to AUL(z). So in uplift mode the resistance</p><p>given by equation (2a) drops from its value P0 when this uplift started, and asymptotically approaches the</p><p>Theory, Environment Theory w</p><p>146</p><p>(negative) ultimate suction resistance Pu-suc(z) if the non-dimensional uplift (ζ0 - ζ) gets large compared to AUL(z).</p><p>See the green curve in the model characteristics diagram below.</p><p>Suction Limit</p><p>Experiments (Bridge et al) have found that suction resistance can only be sustained for a limited displacement past</p><p>the point where the net resistance becomes negative, and suction then decays as uplift continues. To model this the</p><p>resistance given by equation (2a) is limited to be no less than (i.e. no more suction than) a negative lower bound</p><p>Pmin(z), given by:</p><p>Pmin(z) = EUL(z)Pu-suc(z) (2b)</p><p>where</p><p> EUL(z) = exp[Min{0, (z - zP=0) / (λsuc zmax)}]</p><p> zmax = largest ever penetration z for this penetrator</p><p> zP=0 = largest penetration z at which suction has started during any uplift</p><p> λsuc = non-dimensional Normalised Suction Decay Distance parameter of the model, as specified in the Soil</p><p>Model Parameters.</p><p>The exponent in the expression for EUL(z) is zero or negative, so EUL(z) ≤ 1.EUL(z) equals 1 when z ≥ zP=0, but decays</p><p>towards zero if the penetration z is less than the largest penetration, zP=0, at which suction has ever occurred during</p><p>uplift. The effect of this is that the term Pmin(z) limits suction to be no more than Pu-suc(z) when the first uplift starts,</p><p>but as the penetrator lifts up higher (relative to the maximum penetration at which suction has ever occurred</p><p>during uplift) then the suction is limited more. This models the suction decay effect that experimental evidence has</p><p>found.</p><p>Repenetration Mode</p><p>For Repenetration mode the penetration resistance is given by</p><p>P(z) = P0 + HRP(ζ - ζ0)(Pu(z) - P0) (3a)</p><p>but subject to a repenetration resistance upper bound – see below. Here</p><p> ζ0 and P0 = non-dimensional penetration and resistance at the start of this repenetration</p><p> HRP(ζ - ζ0) = (ζ - ζ0) / [ ARP(z) + (ζ - ζ0) ]</p><p> ARP(z) = ( Pu(z)-P0 ) / Pu*</p><p> Pu* = Pu(z) if P0 ≤ 0, i.e. if this repenetration started from a zero or negative resistance</p><p> Pu* = Pu(z*) if P0 > 0, where z* is the penetration when the preceding episode of uplift started</p><p>The term HRP(ζ - ζ0) in equation (3a) is a hyperbolic factor that equals 0 when ζ = ζ0 at the start of this repenetration,</p><p>and asymptotically approaches 1 if the non-dimensional repenetration (ζ - ζ0) gets large compared to ARP(z). So the</p><p>repenetration mode resistance given by equation (3a) rises from its value P0 when this repenetration starts, and</p><p>asymptotically approaches the ultimate penetration resistance Pu(z) if the non-dimensional repenetration (ζ - ζ0)</p><p>gets large compared to ARP(z). See the purple curve in the model characteristics diagram below.</p><p>Repenetration Resistance Reduction After Uplift</p><p>Experiments (Bridge et al) have found that when repenetration occurs following large uplift movement the</p><p>repenetration resistance is reduced until the previous maximum penetration is approached. To model this the</p><p>repenetration resistance given by equation (3a) is limited to be no more than an upper limit Pmax(z) given by:</p><p>Pmax(z) = ERP(z)PIP(z) (3b)</p><p>where</p><p> PIP(z) = penetration resistance that initial penetration mode would give at this penetration, as given by equation</p><p>(1)</p><p> ERP(z) = exp[min{0, - λrep + (z - zP=0) / (λsuc zmax)}]</p><p> zmax = largest ever penetration z for this penetrator</p><p> zP=0 = largest penetration z at which suction has started during any uplift</p><p>w Theory, Environment Theory</p><p>147</p><p> λsuc = non-dimensional Normalised Suction Decay Distance parameter of the model, as specified in the Soil</p><p>Model Parameters.</p><p> λrep = non-dimensional Repenetration Offset After Uplift parameter of the model, as specified in the Soil Model</p><p>Parameters.</p><p>The exponent in the expression for ERP(z) is zero or negative, so ERP(z) ≤ 1. The expression for ERP(z) gives a value <</p><p>1, and so limits the repenetration resistance to be less than the ultimate penetration resistance Pu(z), until the</p><p>penetration z exceeds zP=0 by a certain amount, quantified by λrep. This models the effect that repenetration</p><p>following large uplift movement shows reduced resistance until the previous maximum penetration is approached.</p><p>Model Characteristics</p><p>The following diagram illustrates the effect of the above equations as penetration changes, for a catenary line</p><p>moving up and down on the seabed.</p><p>(5) suction releases</p><p>if repenetrates ..</p><p>5</p><p>Ultimate penetration</p><p>resistance, Pu</p><p>Normal</p><p>seabed</p><p>reaction</p><p>force</p><p>(3) Further uplift is</p><p>resisted by suction</p><p>Non-dimensional</p><p>Penetration, ζ</p><p>(2) Uplift</p><p>(6) Further</p><p>repenetration</p><p>(1) Initial</p><p>penetration</p><p>(4) .. or if uplift</p><p>continues</p><p>O</p><p>-ve reaction</p><p>(ie suction)</p><p>Ultimate suction</p><p>resistance, Pu-suc</p><p>1 2 3 4 10 15 20 25</p><p>Figure: Soil Model Characteristics</p><p>The model starts in Initial Penetration mode and gives a resistance (blue curve, see note (1) in diagram) that</p><p>increases as the pipe sinks into the seabed, and asymptotically approaches the ultimate penetration resistance Pu</p><p>(upper dashed grey curve).</p><p>Then, when the pipe starts to lift up again the model enters Uplift mode and the resistance falls (green curve, see</p><p>note (2) in diagram) and asymptotically approaches the ultimate suction resistance Pu-suc (lower dashed grey curve).</p><p>In this case the uplift is enough that the resistance becomes negative – i.e. suction (note (3) in diagram).</p><p>If the uplift continues and the pipe lifts off the seabed then the model stays in Uplift mode and the model follows the</p><p>green curve further (note (4) in diagram). The suction reduces as the uplift continues, and drops to zero when the</p><p>penetration drops</p><p>106, Issue 1, 46-54.</p><p>Standing RG, Brendling WJ, Wilson D, 1987. Recent Developments in the Analysis of Wave Drift Forces, Low-</p><p>Frequency Damping and Response. OTC paper 5456, 1987.</p><p>Tan Z, Quiggin P, Sheldrake T, 2007. Time domain simulation of the 3D bending hysteresis behaviour of an</p><p>unbonded flexible riser. OMAE paper 29315, 2007 (www.orcina.com/Resources/Papers/OMAE2007-29315.pdf).</p><p>Taylor R and Valent P, 1984. Design Guide for Drag Embedment Anchors, Naval Civil Engineering Laboratory (USA),</p><p>TN No N-1688.</p><p>http://www.orcina.com/Resources/Papers/OMAE2009-79259.pdf</p><p>http://www.orcina.com/Resources/Papers/OMAE2007-29315.pdf</p><p>w Introduction, References and Links</p><p>19</p><p>Torsethaugen K and Haver S, 2004. Simplified double peak spectral model for ocean waves, Paper No. 2004-JSC-193,</p><p>ISOPE 2004 Touson, France.</p><p>Thwaites, 1960. Incompressible Aerodynamics, Oxford, 399-401.</p><p>Timoshenko S,1955. Vibration Problems in Engineering, van Nostrand.</p><p>Triantafyllou M S, Yue D K P and Tein D Y S, 1994. Damping of moored floating structures. OTC 7489, Houston, 215-</p><p>224.</p><p>Tucker et al, 1984. Applied Ocean Research, 6, No 2.</p><p>Tucker M J, 1991. Waves in Ocean Engineering. Ellis Horwood Ltd. (Chichester).</p><p>Wichers J E W, 1979. Slowly oscillating mooring forces in single point mooring systems. BOSS79 (Second</p><p>International Conference on Behaviour of Offshore Structures).</p><p>Wichers J E W, 1988. A Simulation Model for a Single Point Moored Tanker. Delft University Thesis.</p><p>Wu M, Saint-Marcoux J-F, Blevins R D, Quiggin P P, 2008. Paper No. ISOPE-2008-MWU10. ISOPE Conference 2008,</p><p>Vancouver, Canada. (www.orcina.com/Resources/Papers/ISOPE2008-MWU-10.pdf)</p><p>Young A D, 1989. Boundary Layers. BSP Professional Books, 87-91.</p><p>Suppliers of frequency domain VIV software</p><p>SHEAR7</p><p>AMOG Consulting Inc.</p><p>770 South Post Oak Lane, Suite 505</p><p>Houston, TX 77056</p><p>USA</p><p>Attention: Dr. H. Marcollo</p><p>Tel: +1 713 255 0020</p><p>Email: shear7@amogconsulting.com</p><p>VIVA</p><p>JD Marine</p><p>11777 Katy Freeway, Suite 434 South</p><p>Houston, TX 77079</p><p>USA</p><p>Tel: +1 281 531 0888</p><p>Email: info@jdmarineus.com</p><p>http://www.orcina.com/Resources/Papers/ISOPE2008-MWU-10.pdf</p><p>mailto:shear7@amogconsulting.com</p><p>mailto:info@jdmarineus.com</p><p>w Tutorial, Getting Started</p><p>21</p><p>2 TUTORIAL</p><p>2.1 GETTING STARTED</p><p>This short tutorial gives you a very quick run through the model building and results presentation features of</p><p>OrcaFlex.</p><p>On completion of the tutorial we suggest that you also look through the pre-run examples – see Example Files.</p><p>On starting up OrcaFlex, you are presented with a 3D view showing just a blue line representing the sea surface and</p><p>a brown line representing the seabed. At the top of the screen are menus, a tool bar and a status bar arranged in the</p><p>manner common to most Windows software. As usual in Windows software, nearly all actions can be done in</p><p>several ways: here, to avoid confusion, we will usually only refer to one way of doing the action we want, generally</p><p>using the mouse.</p><p>Figure: The OrcaFlex main window</p><p>2.2 BUILDING A SIMPLE SYSTEM</p><p>To start with, we will build a simple system consisting of one line and one vessel only.</p><p>Using the mouse, click on the new vessel button on the toolbar. The cursor changes from the usual pointer to a</p><p>crosshair cursor to show that you have now selected a new object and OrcaFlex is waiting for you to decide where to</p><p>place it. Place the cursor anywhere on the screen and click the mouse button. A "ship" shape appears on screen,</p><p>positioned at the sea surface, and the cursor reverts to the pointer shape. To select the vessel, move the cursor close</p><p>to the vessel and click the mouse button – the message box (near the top of the 3D view) will confirm when the</p><p>vessel has been selected. Now press and hold down the mouse button and move the mouse around. The vessel</p><p>follows the mouse horizontally, but remains at the sea surface. (To alter vessel vertical position, or other details,</p><p>select the vessel with the mouse, then double click to open the Vessel data window.)</p><p>2.3 ADDING A LINE</p><p>Now add a line. Using the mouse, click on the new line button . The crosshair cursor reappears – move the</p><p>mouse to a point just to the right of the vessel and click. The line appears as a catenary loop at the mouse position.</p><p>Move the mouse to a point close to the left hand end of the line, press and hold down the mouse button and move</p><p>the mouse around. The end of the line moves around following the mouse, and the line is redrawn at each position.</p><p>Release the mouse button, move to the right hand end, click and drag. This time the right hand end of the line is</p><p>dragged around. In this way, you can put the ends of the lines roughly where you want them. (Final positioning to</p><p>exact locations has to be done by typing in the appropriate numbers – select the line with the mouse and double</p><p>click to bring up the line data form.)</p><p>Move the line ends until the left hand end of the line is close to the bow of the ship, the right hand end lies above the</p><p>water and the line hangs down into the water.</p><p>Tutorial, Adjusting the View w</p><p>22</p><p>At this point, the line has a default set of properties and both ends are at fixed positions relative to the Global origin.</p><p>For the moment we will leave the line properties (length, mass, etc.) at their default values, but we will connect the</p><p>left hand end to the ship. Do this as follows:</p><p>1. Click on the line near the left hand end, to select that end of the line; make sure you have selected the line, not</p><p>the vessel or the sea. The message box at the left hand end of the status bar tells you what is currently selected.</p><p>If you have selected the wrong thing, try again. (Note that you don't have to click at the end of the line in order</p><p>to select it – anywhere in the left hand half of the line will select the left hand end. As a rule, it is better to choose</p><p>a point well away from any other object when selecting something with the mouse.)</p><p>2. Release the mouse and move it to the vessel, hold down the CTRL key and click. The message box will confirm</p><p>the connection and, to indicate the connection, the triangle at the end of the line will now be the same colour as</p><p>the vessel.</p><p>Now select the vessel again and drag it around with the mouse. The left hand end of the line now moves with the</p><p>vessel. Leave the vessel positioned roughly as before with the line in a slack catenary.</p><p>2.4 ADJUSTING THE VIEW</p><p>The default view of the system is an elevation of the global X-Z plane – you are looking horizontally along the</p><p>positive Y axis. The view direction (the direction you are looking) is shown in the Window Title bar in</p><p>azimuth/elevation form (azimuth=270; elevation=0). You can move your view point up, down, right or left, and you</p><p>can zoom in or out, using the view control buttons near the top left corner of the window. Click on each</p><p>of the top 3 buttons in turn: then click again with the SHIFT key held down. The SHIFT key reverses the action of the</p><p>button. If you want to move the view centre without rotating, use the scroll bars at the bottom and right edges of the</p><p>window. By judicious use of the buttons and scroll bars you should be able to find any view you like.</p><p>Alternatively, you can alter the view with the mouse. Hold down the ALT key and left mouse button and drag. A</p><p>rectangle on screen shows the area which will be zoomed to fill the window when the mouse button is released.</p><p>SHIFT+ALT+left mouse button zooms out – the existing view shrinks to fit in the rectangle.</p><p>Warning: OrcaFlex will allow you to look up at the model from underneath, effectively from under the</p><p>seabed! Because the view is isometric and all lines are visible, it is not always apparent that this</p><p>has occurred. When this has happened, the elevation angle is shown as negative in the title bar.</p><p>There are three shortcut keys which are particularly useful for controlling the view. For example CTRL+P gives a plan</p><p>view from above; CTRL+E gives an elevation; CTRL+Q rotates the view through</p><p>90° about the vertical axis. (CTRL+P</p><p>and CTRL+E leave the view azimuth unchanged.)</p><p>Now click the button on the 3D View to bring up the Edit View Parameters form. This gives a more precise way</p><p>of controlling the view and is particularly useful if you want to arrange exactly the same view of 2 different models –</p><p>say 2 alternative configurations for a particular riser system. Edit the view parameters if you wish by positioning the</p><p>cursor in the appropriate box and editing as required.</p><p>If you should accidentally lose the model completely from view (perhaps by zooming in too close, or moving the</p><p>view centre too far) there are a number of ways of retrieving it:</p><p> Press CTRL+T or right click in the view window and select Reset to Default View.</p><p> Press the Reset button on the Edit View Parameters form. This also resets back to the default view.</p><p> Zoom out repeatedly until the model reappears.</p><p> Close the 3D View and add a new one (use the Window|Add 3D View menu item). The new window will have</p><p>the default view centre and view size.</p><p>2.5 STATIC ANALYSIS</p><p>Note: If you are running the demonstration version of OrcaFlex then this facility is not available.</p><p>To run a static analysis of the system, click on the calculate statics button . The message box reports which line is</p><p>being analysed and how many iterations have occurred. When the analysis is finished (almost instantly for this</p><p>simple system) the Program State message in the centre of the Status Bar changes to read "Statics Complete", and</p><p>the Static Analysis button changes to light grey to indicate that this command is no longer available. The appearance</p><p>of the line will have changed a little. When editing the model, OrcaFlex uses a quick approximation to a catenary</p><p>w Tutorial, Dynamic Analysis</p><p>23</p><p>shape for general guidance only, and this shape is replaced with the true catenary shape when static analysis has</p><p>been carried out. (See Static Analysis for more details).</p><p>We can now examine the results of the static analysis by clicking on the Results button . This opens a Results</p><p>Selection window.</p><p>You are offered the following choices:</p><p> Results in numerical and graphical form, with various further choices which determine what the table or graph</p><p>will contain.</p><p> Results for all objects or one selected object.</p><p>Ignore the graph options for the moment, select Summary Results and All Objects, then click Table. A summary of</p><p>the static analysis results is then displayed in spreadsheet form. Results for different objects are presented in</p><p>different sheets. To view more static analysis results repeat this process: click on the Results button and select as</p><p>before.</p><p>2.6 DYNAMIC ANALYSIS</p><p>We are now ready to run the simulation. If you are running the demonstration version of OrcaFlex then you cannot</p><p>do this, but instead you can load up the results of a pre-run simulation – see Examples.</p><p>Click the Run Dynamic Simulation button . As the simulation progresses, the status bar reports current</p><p>simulation time and expected (real) time to finish the analysis, and the 3D view shows the motions of the system as</p><p>the wave passes through.</p><p>Click the Start Replay button . An animated replay of the simulation is shown in the 3D view window. Use the</p><p>view control keys and mouse as before to change the view. The default Replay Period is Whole Simulation. This</p><p>means that you see the simulation start from still water, the wave building and with it the motions of the system.</p><p>Simulation time is shown in the Status bar, top left. Negative time means the wave is still building up from still water</p><p>to full amplitude. At the end of the simulation the replay begins again.</p><p>The replay consists of a series of "frames" at equal intervals of time. Just as you can "zoom" in and out in space for a</p><p>closer view, so OrcaFlex lets you "zoom" in and out in time. Click on the Replay Parameters button , edit Interval</p><p>to 0.5s and click OK. The animated replay is now much jerkier than before because fewer frames are being shown.</p><p>Now click again on Replay Parameters, set Replay Period to Latest Wave and click on the Continuous box to deselect.</p><p>The replay period shown is at the end of the simulation and has duration of a single wave period. At the end of the</p><p>wave period the replay pauses, then begins again.</p><p>Now click on the Replay Step button to pause the replay. Clicking repeatedly on this button steps through the</p><p>replay one frame at a time – a very useful facility for examining a particular part of the motion in detail. Click with</p><p>the SHIFT key held down to step backwards.</p><p>You can then restart the animation by clicking on 'Start Replay' as before. To slow down or speed up the replay, click</p><p>on Replay Parameters and adjust the speed. Alternatively use the shortcuts CTRL+F and SHIFT+CTRL+F to make the</p><p>replay faster or slower respectively.</p><p>To exit from replay mode click on the Stop Replay button .</p><p>2.7 MULTIPLE VIEWS</p><p>You can add another view of the system if you wish by clicking on the View button . Click again to add a third</p><p>view, etc. Each view can be manipulated independently to give, say, simultaneous plan and elevation views. To make</p><p>all views replay together, click on Replay Control and check the All Views box. To remove an unwanted view simply</p><p>close its view window. To rearrange the screen and make best use of the space, click Window and choose Tile</p><p>Vertical (F4) or Tile Horizontal (SHIFT+F4). Alternatively, you can minimise windows so that they appear as small</p><p>icons on the background, or you can re-size them or move them around manually with the mouse. These are</p><p>standard Windows operations which may be useful if you want to tidy up the screen without having to close a</p><p>window down completely.</p><p>Tutorial, Looking at Results w</p><p>24</p><p>2.8 LOOKING AT RESULTS</p><p>Now click on the Results button . This opens a Results Selection window.</p><p>You are offered the following choices:</p><p> Results as Tables or Graphs, with various further choices which determine what the table or graph will contain.</p><p> Results for all objects or one selected object.</p><p>Select Time History for any line, then select Effective Tension at End A and click the Graph button. The graph</p><p>appears in a new window. You can call up time histories of a wide range of parameters for most objects. For lines,</p><p>you can also call up Range Graphs of effective tension, curvature, bend moment and many other variables. These</p><p>show maximum, mean and minimum values of the variable plotted against position along the line. Detailed</p><p>numerical results are available by selecting Summary Results, Full Results, Statistics and Linked Statistics.</p><p>Time history and range graph results are also available in numerical form – select the variable you want and press</p><p>the Values button. The results can be exported as Excel compatible spreadsheets for further processing as required.</p><p>Further numerical results are available in tabular form by selecting Summary Results, Full Results, Statistics and</p><p>Linked Statistics.</p><p>Results Post-Processing</p><p>Extra post-processing facilities are available through Excel spreadsheets.</p><p>2.9 GETTING OUTPUT</p><p>You can get printed copies of data, results tables, system views and results graphs by means of the File | Print</p><p>menu, or by clicking Print on the pop-up menu. Output can also be transferred into a word processor or other</p><p>application, either using copy and paste via the clipboard or else export/import via a file.</p><p>Note: Printing and export facilities are not available in the demonstration version of OrcaFlex.</p><p>2.10 INPUT DATA</p><p>Take a look through the input data forms. Start by resetting the program: click on the Reset button . This returns</p><p>OrcaFlex to the reset state, in which you can edit the data freely. (While a simulation is active you can only edit</p><p>certain non-critical items, such as the colours used for drawing.)</p><p>Now click on the Model Browser button . This displays the data structure in tree form in the Model Browser.</p><p>Select an item and</p><p>double click with the mouse to bring up the data form. Many of the data items are self</p><p>explanatory. For details of a data item, select the item with the mouse and press the F1 key. Alternatively use the</p><p>question mark Help icon in the top right corner of the form. Have a look around all the object data forms available to</p><p>get an idea of the capabilities of OrcaFlex.</p><p>End of Tutorial</p><p>We hope you have found this tutorial useful. To familiarise yourself with OrcaFlex, try building and running models</p><p>of a number of different systems. The manual also includes a range of examples which expand on particular points of</p><p>interest or difficulty.</p><p>Finally, please remember that we at Orcina are on call to handle your questions if you are stuck.</p><p>Content/html/Menus__File_Menu.htm</p><p>w User Interface, Introduction</p><p>25</p><p>3 USER INTERFACE</p><p>3.1 INTRODUCTION</p><p>3.1.1 Program Windows</p><p>OrcaFlex is based upon a main window that contains the Menus, a Tool Bar, a Status Bar and usually at least one 3D</p><p>view. The window caption shows the program version and the file name for the current model.</p><p>Figure: The OrcaFlex main window</p><p>Within this main window, any number of child windows can be placed which may be:</p><p>3D View Windows showing 3D pictorial views of the model</p><p>Graph Windows showing results in graphical form</p><p>Spreadsheet Windows showing results in numerical form</p><p>Text Windows reporting status</p><p>Additional temporary windows are popped up, such as Data Forms for each object in the model (allowing data to be</p><p>viewed and modified) and dialogue windows (used to specify details for program actions such as loading and saving</p><p>files). While one of these temporary windows is present you can only work inside that window – you must dismiss</p><p>the temporary window before you can use other windows, the menus or toolbar.</p><p>The actions that you can perform at any time depend on the current Model State.</p><p>Arranging Windows</p><p>3D View, Graph, Spreadsheet and Text Windows may be tiled so that they sit side-by-side, but they must remain</p><p>within the bounds of the main window. The program rearranges the windows every time a new window is created.</p><p>3.1.2 The Model</p><p>OrcaFlex works by building a mathematical computer model of your system. This model consists of a number of</p><p>objects that represent the parts of the system – e.g. vessels, buoys, lines etc.</p><p>Each object has a name, which can be any length. Object names are not case-sensitive, so Riser, riser and RISER</p><p>would all refer to the same object. This behaviour is the same as for Windows file names.</p><p>The model always has two standard objects:</p><p> General contains general data, such as title, units etc.</p><p> Environment represents the sea, seabed, waves, current etc.</p><p>You can then use the Model Browser or the toolbar to add other objects to represent the parts of your system. There</p><p>is no limit, other than the capacity of your computer, to the number of objects you can add to the model. At any time,</p><p>you can save your model to a data file.</p><p>User Interface, Introduction w</p><p>26</p><p>3.1.3 Model States</p><p>OrcaFlex builds and analyses a mathematical model of the system being analysed, the model being built up from a</p><p>series of interconnected objects, such as Lines, Vessels and Buoys. For more details see Modelling and Analysis.</p><p>OrcaFlex works on the model by moving through a sequence of states, the current state being shown on the status</p><p>bar. The following diagram shows the sequence of states used and the actions, results etc. available in each state.</p><p>RESET</p><p>Calculating</p><p>Statics</p><p>Simulating</p><p>STATICS COMPLETE</p><p>SIMULATION</p><p>COMPLETE</p><p>Calculate</p><p>Static</p><p>Position</p><p>Reset</p><p>Reset</p><p>Edit or</p><p>Reset</p><p>Run</p><p>Pause</p><p>Run</p><p>SIMULATION</p><p>PAUSED</p><p>Reset</p><p>Extend</p><p>Simulation</p><p>SIMULATION</p><p>UNSTABLE</p><p>Reset</p><p>Figure: Model States</p><p>The states used are as follows:</p><p>Reset</p><p>The state in which OrcaFlex starts. In Reset state you can freely change the model and edit the data. No results are</p><p>available.</p><p>Calculating Statics</p><p>OrcaFlex is calculating the statics position of the model. You can abort the calculation by CLICKING the Reset button.</p><p>Statics Complete</p><p>The statics calculation is complete and the static position results are available. You are allowed to make changes to</p><p>the model when in this state but if you make any changes (except for very minor changes like colours used) then the</p><p>model will be automatically reset and the statics results will be lost.</p><p>Simulating</p><p>The dynamic simulation is running. The results of the simulation so far are available and you can examine the model</p><p>data, but only make minor changes (e.g. colours used). You cannot store the simulation to a file while simulating –</p><p>you must pause the simulation first.</p><p>w User Interface, Introduction</p><p>27</p><p>Simulation Paused</p><p>There is a simulation active, but it is paused. The results so far are available and you can examine the model data.</p><p>You can also store the part-run simulation to a file.</p><p>Simulation Complete</p><p>The simulation is complete. The simulation results are available and you can store the results to a simulation file for</p><p>later examination. You must reset the model, by CLICKING on the Reset button, before significant changes to the</p><p>model can be made.</p><p>You can use the Extend Dynamic Simulation facility if you wish to simulate for a further period of time.</p><p>Simulation Unstable</p><p>The simulation has become unstable. The simulation results are available and you can store the results to a</p><p>simulation file for later examination. This allows you to try and understand why the simulation has become</p><p>unstable. You may also want to examine the results up until the point at which the simulation became unstable.</p><p>However, please treat these results with caution – because the simulation eventually went unstable this indicates</p><p>that the dynamic simulation may not have converged at earlier simulation times.</p><p>You must reset the model, by CLICKING on the Reset button, before significant changes to the model can be made.</p><p>Typical model state flow</p><p>To illustrate how model states work, here is an example of a typical working pattern:</p><p>1. In Reset state, open a new model from a data file or use the current model as the starting point for a new model.</p><p>2. In Reset state, add or remove objects and edit the model data as required for the new model. It is generally best</p><p>to use a very simple model in the early stages of design and only add more features when the simple model is</p><p>satisfactory.</p><p>3. Run a static analysis (to get to Statics Complete state) and examine the static position results. Make any</p><p>corrections to the model that are needed – this will automatically reset the model. Steps (2) and (3) are</p><p>repeated as required.</p><p>4. Run a simulation and monitor the results during the simulation (in Simulating state).</p><p>5. If further changes to the model are needed then Reset the model and edit the model accordingly. Steps (2) to</p><p>(5) are repeated as required.</p><p>6. Finalise the model, perhaps improving the discretisation (for example by reducing the time step sizes or</p><p>increasing the number of segments used for Lines). Run a final complete simulation (to reach</p><p>Simulation Complete state) and generate reports using the results.</p><p>3.1.4 Toolbar</p><p>The toolbar holds a variety of buttons that provide quick access to the most frequently used menu items. The</p><p>selection of buttons available varies with the current Program State.</p><p>Button Action Equivalent Menu Item</p><p>Open File | Open</p><p>Save File | Save</p><p>Model Browser Model | Model Browser</p><p>New Vessel Model | New Vessel</p><p>New Line Model | New Line</p><p>New 6D Buoy Model | New 6D Buoy</p><p>New 3D Buoy Model | New 3D Buoy</p><p>New Winch Model | New Winch</p><p>New Link Model | New Link</p><p>User Interface, Introduction w</p><p>28</p><p>Button Action Equivalent Menu Item</p><p>New Shape Model | New Shape</p><p>Calculate Statics Calculation | Single Statics</p><p>Run Simulation Calculation | Run Dynamic Simulation</p><p>Pause Simulation Calculation | Pause Dynamic Simulation</p><p>Reset Calculation</p><p>| Reset</p><p>Start Replay Replay | Start Replay</p><p>Stop Replay Replay | Stop Replay</p><p>Step Replay Forwards Replay | Step Replay Forwards</p><p>Edit Replay Parameters Replay | Edit Replay Parameters</p><p>Add New 3D View Window | Add 3D View</p><p>Examine Results Results | Select Results</p><p>Help Contents and Index Help | OrcaFlex Help</p><p>3.1.5 Status Bar</p><p>The Status Bar is divided into three fields:</p><p>The Message Box</p><p>This is at the left hand end. It shows information about the progress of the current action, such as the name of the</p><p>currently selected object, or the current iteration number or simulation time. Error messages are also shown here.</p><p>When a statics calculation is done messages showing the progress of the calculation are shown in the message box.</p><p>To see all the messages from the statics calculation CLICK on the message box – the Statics Progress Window will</p><p>then be opened.</p><p>The Program State Indicator</p><p>In the centre and shows which state the program is in (see Model States).</p><p>The Information Box</p><p>This is on the right. It shows additional information, including:</p><p> The global coordinates of the position of the cursor, in the current view plane.</p><p> Distances when using the measuring tape tool.</p><p>3.1.6 Mouse and Keyboard Actions</p><p>As well as the standard Windows mouse operations such as selection and dragging OrcaFlex uses some specialised</p><p>actions. Clicking the right mouse button over a 3D View, Graph or Text Window displays a pop-up menu of</p><p>frequently used actions, such as Copy, Paste, Export etc. For wire frame 3D Views and Graph Windows the mouse</p><p>can be used for zooming. Simply hold the ALT key down and using the left mouse button, drag a box over the region</p><p>you want to view.</p><p>All of the menu items can be selected from the keyboard by pressing ALT followed by the underlined letters.</p><p>Example: To exit from the program (menu: File | Exit) press ALT+F then X, or ALT then F then X</p><p>A number of frequently used menu items may also be accessed by shortcut keys, such as CTRL+R to start a replay.</p><p>See the tables below. The shortcut keys are also displayed on the OrcaFlex menus. We suggest that as you become</p><p>more familiar with the operation of OrcaFlex that you memorise some of the shortcut keys for actions that you use</p><p>frequently.</p><p>w User Interface, Introduction</p><p>29</p><p>Keys on Main Window</p><p>New model CTRL+N</p><p>Open file CTRL+O</p><p>Save file CTRL+S</p><p>Open data SHIFT+CTRL+O</p><p>Save data SHIFT+CTRL+S</p><p>Help F1</p><p>Print F7</p><p>Show / hide Model Browser F6</p><p>Switch to Model Browser SHIFT+F6</p><p>Calculate static position F9</p><p>Run dynamic simulation F10</p><p>Pause dynamic simulation F11</p><p>Reset F12</p><p>Open results selection form F5</p><p>Go to next window CTRL+F6</p><p>Go to previous window SHIFT+CTRL+F6</p><p>Tile windows vertically F4</p><p>Tile windows horizontally SHIFT+F4</p><p>Close selected window CTRL+F4</p><p>Close program ALT+F4</p><p>Keys on Model Browser</p><p>View by Groups CTRL+ALT+G</p><p>Edit data ENTER</p><p>Move selected objects CTRL+M</p><p>Rename object F2</p><p>Locate F3</p><p>Compare F8</p><p>Lock / Unlock objects CTRL+L</p><p>Hide/Show CTRL+H</p><p>Properties ALT+ENTER</p><p>Cut CTRL+X</p><p>Copy CTRL+C</p><p>Paste CTRL+V</p><p>Delete DELETE</p><p>Switch to Main Window SHIFT+F6</p><p>Close browser F6</p><p>Keys on Data Forms</p><p>Help F1</p><p>Go to next data form F6</p><p>Go to previous data form SHIFT+F6</p><p>Display batch script names for currently selected</p><p>data item or table.</p><p>F7</p><p>User Interface, Introduction w</p><p>30</p><p>Display Properties Report ALT+ENTER</p><p>Show connections report F8</p><p>Copy form F9</p><p>Export form F10</p><p>Print form CTRL+P</p><p>Open calculator F12</p><p>Data Selection Keys</p><p>Go to next data item or table TAB</p><p>Go to previous data item or table SHIFT+TAB</p><p>Go to data item or table labelled with underlined letter ALT+LETTER</p><p>Move around within a table ← → ↑ ↓</p><p>Select multiple cells in table SHIFT + ← → ↑ ↓</p><p>SHIFT+HOME</p><p>SHIFT+END</p><p>Go to first or last column in table HOME END</p><p>Go up or down table several rows at a time PGUP PGDN</p><p>Data Editing Keys</p><p>Enter new value for selected cell Type new value</p><p>Edit current value of selected cell F2</p><p>Open drop-down list ALT + ↑ ↓</p><p>Move around within new data value being entered ← → HOME END</p><p>Accept edit ENTER</p><p>Accept edit and go to adjacent cell in table ↑ ↓</p><p>Cancel edit ESC</p><p>Copy selected cell(s) to clipboard CTRL+C</p><p>Paste from clipboard CTRL+V</p><p>Fill selection from top (copy top cell down) CTRL+D</p><p>Fill selection from left (copy leftmost cell to right) CTRL+R</p><p>Fill selection from bottom (copy bottom cell up) CTRL+U</p><p>SHIFT+CTRL+D</p><p>Fill selection from right (copy rightmost cell to left) CTRL+L</p><p>SHIFT+CTRL+R</p><p>Insert new rows in table INSERT</p><p>Delete selected rows from table DELETE</p><p>Graph Control Keys</p><p>Use default ranges CTRL+T</p><p>Zoom ALT+drag, CTRL+wheel</p><p>Pan SHIFT+drag</p><p>3D View Control Keys</p><p>Elevation view CTRL+E</p><p>Plan view CTRL+P</p><p>Rotate viewpoint up (increment view elevation angle) CTRL+ALT+↑</p><p>Rotate viewpoint down (decrement view elevation angle) CTRL+ALT+↓</p><p>Rotate viewpoint right (increment view azimuth angle) CTRL+ALT+→</p><p>w User Interface, OrcaFlex Model Files</p><p>31</p><p>Rotate viewpoint left (decrement view azimuth angle) CTRL+ALT+←</p><p>Rotate viewpoint +90° CTRL+Q</p><p>Rotate viewpoint -90° SHIFT+CTRL+Q</p><p>Zoom In CTRL+I, CTRL+wheel, ALT+drag</p><p>Zoom Out SHIFT+CTRL+I, CTRL+wheel, SHIFT+ALT+drag</p><p>Move view centre – mouse panning SHIFT+drag</p><p>Move view centre – fine adjustment ← → ↑ ↓</p><p>Move view centre – coarse adjustment CTRL + ← → ↑ ↓</p><p>Edit view parameters for current 3D view CTRL+W</p><p>Reset to default view CTRL+T</p><p>Set as default view SHIFT+CTRL+T</p><p>Show entire model CTRL+ALT+T</p><p>3D View Control Keys (for wire frame graphics only)</p><p>Show / Hide local axes CTRL+Y</p><p>Show / Hide node axes CTRL+ALT+Y</p><p>Undo most recent drag CTRL+Z</p><p>Lock/Unlock selected object CTRL+L</p><p>Place new object SPACE or ENTER</p><p>Edit selected object CTRL+F2</p><p>Cut selected object to clipboard CTRL+X</p><p>Copy selected object, or view if none selected,</p><p>to clipboard</p><p>CTRL+C</p><p>Paste object from clipboard (followed by mouse click</p><p>or ENTER to position the new object)</p><p>CTRL+V</p><p>Delete selected object DELETE</p><p>Measuring tape tool SHIFT+CTRL+drag</p><p>Replay Control Keys</p><p>Start / Stop replay CTRL+R</p><p>Replay faster CTRL+F</p><p>Replay slower SHIFT+CTRL+F</p><p>Step forwards one frame in the replay and pause CTRL+A</p><p>Step backwards one frame in the replay and pause CTRL+B</p><p>Edit replay parameters CTRL+D</p><p>3.2 ORCAFLEX MODEL FILES</p><p>3.2.1 Data Files</p><p>OrcaFlex models are saved to either binary data files (.dat) or text data files (.yml).</p><p>All versions of OrcaFlex can read binary data files. Text data files were only introduced in version 9.3a and so cannot</p><p>be read by older versions of the program.</p><p>Binary data files have strong version compatibility features. For example, when OrcaFlex attempts to open a binary</p><p>data file written by a later version of the program it is able to report informative compatibility warnings. The</p><p>program is not able to be as helpful and informative when working with text data files across program versions.</p><p>Whilst we strive to achieve as much compatibility as possible for text data files across program versions, we cannot</p><p>achieve the same level of compatibility as that for binary data files.</p><p>User Interface, OrcaFlex Model Files w</p><p>32</p><p>Text data files, as written by OrcaFlex, contain only data that is active in the model. For example, if implicit time</p><p>integration is selected in the model then all data relating to explicit time integration is excluded from the text data</p><p>file. On the other hand, binary data files contain all data whether or not it is active. The fact that the binary data file</p><p>contains inactive data can be very useful and so, in general, we would recommend that model building and</p><p>development is performed using the binary data file.</p><p>Text data files can be created without the use of OrcaFlex simply by entering text into a text editor. In general we</p><p>would not advocate this approach to model building. For very simple systems it may be a practical approach but</p><p>more complex models are usually</p>
- Avaliação de Pré-Cálculo
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- INTERPRETAÇÃO E PRODUÇÃO DE TEXTOS
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