OrcaFlex 9.0

The latest release of OrcaFlex 9.0 is OrcaFlex 9.0g. To upgrade to OrcaFlex 9.0g, download the following zip file:
  OrcaFlex-Patch-9.0a-or-9.0d-or-9.0e-or-9.0f-to-9.0g.zip (5.4 MB)
extract all the files it contains to a single folder and then run the extracted file called patch.exe.

This patch can only be applied if you are currently using an earlier release of version 9.0.

The new features introduced in OrcaFlex 9.0 are described below. For full details please download the following zip file: FlexHelp.zip (1.9 MB) and save the files it contains. You can then open the saved .hlp file and open the What's New topic in the Introduction chapter of the contents, and follow the links from there to other parts of the help file.

New in Version 9.0g

Bug fixes

Version 9.0f introduced a number of problems with the handling of windows in OrcaFlex. These problems would occur when switching between different applications (e.g. using the Windows taskbar, ALT+TAB etc.) Upon returning the focus to OrcaFlex problems such as windows losing the focus, or even becoming hidden behind other windows could occur.

We believe that version 9.0g resolves all these problems.

New in Version 9.0f

The VIV Toolbox is no longer a separately licensed module. It is now included with OrcaFlex as standard at no extra cost.

New in Version 9.0e

Bug fixes

• Clashing results were misreported in versions 9.0b, 9.0c and 9.0d. Clash Force, Clash Energy and Clash Impulse were all reported as zero. In addition the Line Clashing Report was not reporting any clash events. Please note that the bug only affected the reported results. The contact force was being applied correctly and reported tensions, positions etc. are all correct.
• Under rare circumstance, OrcaFlex was falsely reporting Euler Buckling infringements when using the implicit integrator. This bug affected all earlier 9.0 releases.

Both of these bugs have now been fixed in version 9.0e.

New in Version 9.0d

Bug fix

Multiple statics results for cases with seabed friction in statics were wrong in version 9.0a to 9.0c inclusive. This bug is fixed in version 9.0d.

New in Version 9.0c

In the data for the default vessel type, the hydrodynamic drag and wind drag yaw coefficients had the wrong signs. This has now been corrected.

New in Version 9.0b

• We have made a number of performance improvements for implicit integration. Please note that these do not affect all cases. Principally we have improved the performance for a number of cases which were not being handled well by version 9.0a.
• The reporting of simulation time remaining is now more stable when using implicit integration.
• A Pause Batch button has been added to the batch form.
• In version 9.0a simulations of models with a large number of elastic solids could be significantly slower than in earlier versions. This problem has been fixed and run times in 9.0b for such models are now as fast as in earlier versions.
• When you import added mass and damping data for a Vessel Type, the data are now automatically scaled from the units system in the input file to the units of the OrcaFlex model.

Bug fixes

The following bugs have been found in version 9.0a. They have all been fixed in version 9.0b.

• When using implicit integration and line-on-line clashing the Line Clash Impulse result and the Line Clashing Report were incorrect. Note that other results when using implicit integration and line-on-line clashing were unaffected.
• OrcaFlex spreadsheets can be added to the batch form and processed as part of the batch. In version 9.0a this feature was not working.
• Version 9.0a was not working properly on Windows 98 and ME. An "Access Violation" error message was being displayed when you loaded a simulation file or ran a simulation.

New in Version 9.0a (released September 2006)

Implicit integration

A new implicit time integration scheme has been added. The new integration scheme is an option - the existing explicit time integration scheme is still available.

Implicit integration can offer very significant performance benefits, especially for stiff systems (models with very high stiffness values, such as steel pipes) or for models with very fine segmentation.

The Implicit Integration page gives more detailed information and guidance for the using the implicit integrator.

Whole System statics

Whole System statics is a new alternative system statics method that complements the existing Separate Buoy and Line statics method. For systems with many Buoys or Vessels included in the static analysis, it can converge much better than the Separate Buoy and Line statics method.

Line interaction with the seabed or elastic solids

Contact between lines and the seabed or elastic solids now allows for the line's diameter. A contact diameter data item has been added, so the contact diameter can be independent of the outer diameter.

A new data item, Height above seabed, has been added. This is only available for Anchored connections and is used to help ensure that end nodes can be positioned to sit on top of the seabed. See the Line Data: Connections topic for full details.

These changes may require you to update data files prepared with older versions of OrcaFlex. In particular you should be aware of the following issues:

• Anchored connections were commonly set up with z=0 in previous versions of OrcaFlex which placed the centreline at the seabed. In this version of OrcaFlex this can result in the end node becoming 'buried' in the seabed which can lead to spurious curvature, bend moment etc. results. The solution is to set Height above seabed to 0. This results in the z coordinate being raised one radius above the seabed - see Height above seabed for more details.
• In old data files some elastic solid sizes or positions might have been specified to be slightly different from their real values, to compensate for previous versions of OrcaFlex not allowing for line contact diameter. Since the contact diameter is now handled by OrcaFlex the solid sizes and positions should be set to their real values.

Lines

• A Lift Coefficient can now be specified for Line Types and is intended for use for seabed stability analysis. The lift force that results is normal to the line and normal to the relative flow direction. The lift coefficient can be constant, vary with Reynolds number, vary with height above seabed or vary with both Reynolds number and height above seabed. The lift coefficient is also available as a results variable.
• The Line Type normal Drag Coefficients can now be specified to vary with height above seabed or vary with both Reynolds number and height above seabed. The previous options of being constant or varying with Reynolds number are still available.
• New Drag / Lift diameters have been added for Line Types and are used when calculating drag area and lift area. Previously the buoyancy diameter was used for this purpose. These new data items allow greater modelling flexibility and are particularly useful when the line geometry is not cylindrical.
• The friction bias power data item has been removed. This was necessary in order implement the new implicit integration scheme. The Seabed Friction topic gives full details of the seabed friction model used by OrcaFlex.
• Line Curvature component, Bend Moment component, Shear Force component, ZZ strain and Bend Radius results variables have been added.
• Line results logging can optionally be disabled on a Line by Line basis. This can be useful if you need to reduce the size of simulation files. Of course, if you choose to disable results logging a Line then OrcaFlex will not be able to provide simulation results for that Line.
• Time history graphs for the touchdown point of a Line now behave differently if there is no touchdown node. In previous versions in this circumstance the graph would report a value of 0. In version 9.0 and later the program reports N/A (meaning 'not available') and the graph shows no value.
• The hysteretic bend stiffness profile graph (available from the variable data form) now shows the hysteresis loop.
• The Full Statics convergence parameters have been simplified and more thoroughly documented.

Environment

• The Torsethaugen double peaked wave spectrum has been added.
• There is now an option for OrcaFlex to choose random wave seeds automatically.
• A Shear Seabed Stiffness data item has been added. This value was used by older versions of the program but was not available for editing by the user and was taken to be the Normal Seabed Stiffness.

General Data

• New force units tonnes-force (tef) and kilograms-force (kgf) have been added.
• User specified units now allow the gravitational constant g to be specified.
• New data items have been added which allow user control of the recommended outer time step for explicit integration.

Vessels and Buoys

• Vessel damping is now calculated from vessel velocity relative to global axes. Previously, vessel velocity relative to current was used, but this can give artificially high damping loads on vessels moored in current. Note that this change will affect results in some models.
• Vessel added mass and damping can now be frequency dependent.
• Damping load results are now available for vessels.
• Vessel prescribed motion was previously restricted so that the velocity was forced to be in the same direction as the vessel heading. This restriction has now been lifted.
• The default vessel type data (set up when you create a new vessel type) has been improved.
• Vessel and 6D Buoy data forms now show a preview of the wire frame drawing data.
• 6D Buoy and Vessel position results can now report position at specified point on the object.
• Velocity and Acceleration results for 6D Buoys and Vessels have been added. These are also reported at a specified point on the object.
• Spar Buoys and Towed Fish can now be made hollow by specifying an ID. Inertial effects (mass, fluid inertia loads etc.) for the fluid contained in the hollow part are included. These inertial effects are only included in directions normal to the buoy.
• Velocity and Acceleration results variables have been added for 3D Buoys.
• Lumped Buoys can now have full 6x6 added mass and fluid inertia matrices. In previous versions you could only specify the diagonal entries of these matrices.
• The Centre of Mass for a 6D Buoy can now be specified to be different from the buoy origin.
• The RAOs and matrices option for 6D Buoys now allows specification of the origin at which RAO, added mass and damping effects are added. In addition this RAOs and matrices option is no longer available for Towed Fish because the symmetry assumptions are not valid for Towed Fish.
• Lumped Buoys with no vertices no longer contact with shapes or the seabed. In previous versions such buoy's were treated as having a single contact vertex at the buoy origin.

User Interface

• The All Lines Data Form has been superseded by the All Objects Data Form which incorporates all the functionality of the previous All Lines Data Form. The form allows simultaneous viewing or editing of properties of multiple objects. Previously this was restricted to Lines, but in addition the form now supports Vessels, 6D Buoys, 3D Buoys, Links, Winches and Shapes. Finally, the form now allows simultaneous editing of section data for all Lines in the model.
• Custom replays can now control the graphics mode and set it to be either Wire frame or Shaded.
• OrcaFlex generates various warning messages when performing calculations. In previous versions of the program these were only displayed if you were in interactive mode, i.e. not using batch mode or Distributed OrcaFlex. These warnings can now be viewed after a simulation has been run from the Calculation | View Warnings menu item.
• The Use Calculated Positions feature can now use the positions from the active replay time.
• Drag rotation in the Shaded drawing view mode now allows rotation about the viewer position. This is achieved using CTRL+ALT+drag.

Results

• Spectral density results are calculated with a modified algorithm designed to reduce the 'noise' or 'leakage' present in the graphs.
• The built-in spreadsheet has been changed to use a different piece of 3rd party software. This brings the following benefits: mouse wheel scroll is now supported; copy to clipboard now includes full floating point precision together with formatting information (borders, colours, bold etc.); saving to .xls files use the latest Excel file format.

Wave Scatter Conversion and Fatigue Analysis

• The Wave Scatter Conversion tool can now create a script table spreadsheet which can be pasted into an OrcaFlex Excel spreadsheet. This is an alternative to the existing Export Batch Script option.
• The default Number of Thetas (station count) for the Fatigue Analysis module has been increased from 8 to 16 (this corresponds to 22.5° intervals).

Line Setup Wizard

• The Line Setup Wizard adjusts line configuration to achieve specified target tensions or declinations. Previously it did this by adjusting either the length of the first section of the line or by adjusting the anchor position. The Wizard has been enhanced to allow variation of length for a user specified section of the line.
• The Line Setup Wizard now allows you to specify target tensions and declinations at both ends of the line.

Automation

New Range Graph Min, Range Graph Max and Rainflow Half Cycle Count instructions have been added to the OrcaFlex spreadsheet.

OrcaFlex Programming Interface

• Three new functions have been added to the OrcaFlex Programming Interface. These are C_GetNumOfWarnings, C_GetWarningText and OrcinaNullReal.
• New fields have been added to the TObjectExtra2, TViewParameters, TExternalFunctionInfo and TBuoyInstantaneousCalculationData structures.

For full details please refer to the OrcFxAPI help file.

Bug fixes

• In version 8.7 the mouse drag rotation (CTRL+drag) feature could change the connections of selected objects as well as rotating the view.
• Wave drift load was not being ramped correctly in previous versions. In practical terms this doesn't really matter because results from the ramped build-up stage should never be used.

These problems have all been fixed.