What's new in this version

• What was new in previous versions
• What's new in OrcaWave

A more in depth discussion of the major new features introduced in 11.5 is available on our blog.

New in version 11.5e

Bug fix

• In version 11.5d only, it was not possible to assign variable data sources to variable data items in the GUI.

This bug is fixed in version 11.5e.

New in version 11.5d

Bug fixes

• Running models with line feeding would sometimes result in an access violation error when the range of the ramping zone was far from the zero of simulation time.
• Running a frequency domain simulation that contained an indirectly solved constraint with no out-frame connection resulted in an unexpected program error.
• Following a frequency domain simulation, the y-component of the line node acceleration was omitted from the list of available line result variables.
• Current vertical stretching was applied to the tabular current velocity field, but not the acceleration field. Current vertical stretching should be applied to both.
• The OrcaFlex spreadsheet did not handle additional data for turbine results which specify a clearance line name.
• Variation models or restart analyses loaded from text data files could sometimes load incorrectly for models containing lines that use the calculated from end positions option to determine their length and end orientations.
• In the frequency domain, the load associated with a change in the proportion wet of a surface piercing 3D buoy, due to wave elevation, was phased incorrectly.
• The disturbed sea surface elevation associated with sea state RAOs may have been calculated incorrectly when the global Z coordinate of mean water level was non-zero. This issue would have affected linear wave components when sea state RAOs were interpolated on position, direction and period. This bug may have affected surface piercing calculations performed as part of the simulation.
• OrcaWave results for sectional bodies in a non-inertial units system, for example US units, were imported incorrectly into OrcaFlex. Specifically, the vessel type datum buoyancy load was imported incorrectly.
• Requesting line solid contact force results would lead to an unexpected program error for protected line nodes whose contact diameters are greater than that of the corresponding stiffener line node.

These bugs are fixed in version 11.5d.

New in version 11.5c

Lines

• For lines which specify axial static-dynamic stiffness, the details page of the line properties report now includes a table reporting the axial stiffnesses used in statics and in dynamics.

Bug fixes

• Deleting a body from a multibody group in a variation model or restart analysis could have resulted in an unexpected program error.
• The edit data as text feature would fail to apply modifications to the model in some situations. This would happen for variation models or restart analyses with parent models in different folders from the child.
• When solving in the frequency domain, hydrodynamic effects below the seabed were not being suppressed for lines with a P-y model.
• The compound page of the line properties report was not being updated when the report relative to object was changed. Similarly, the line type properties report was not being updated when the contents density was changed.
• Prescribed motion vessels may have restarted from the wrong position when performing a mid-simulation restart analysis.
• Editing a current data set in the user interface may have triggered an access violation error after loading a variation model or restart analysis that had been saved in binary format.
• Mid-simulation restarts require a parent simulation file which includes time domain dynamic analysis. OrcaFlex was previously not enforcing this. So, if the parent simulation file was a static state simulation, then OrcaFlex would proceed with the restart, but the resulting analysis would have been invalid.
• The angular velocity and angular acceleration of a curvilinear constraint's out-frame would have been computed incorrectly when there were fewer than two free rotational degrees of freedom and the rotational motion of the out-frame (relative to the in-frame) was not confined to a straight line through the origin of the rotational coordinate space parameterised by $Rx$, $Ry$ and $Rz$. A necessary, but not sufficient, condition to trigger the bug was that there was more than one nonzero component of rotation.
• Calculating time domain panel pressure results may have triggered an invalid multidimensional array arguments error if the corresponding OrcaWave model included only one wave heading.
• Restart analyses restarting from a paused parent simulation may have failed to run if they contained either winches or prescribed motion vessels.
• Restart analyses with line feeding could occasionally report a spurious insufficient inactive line has been defined warning.
• External functions which extract seabed normal resistance results could fail with an access violation error.
• Importing full QTFs from OrcaWave could fail with an error message that the full QTFs contain an unexpected wave frequency.
• Earlier 11.5 versions could sometimes report stiffener lines should have an inner contact diameter that is greater than the outer contact diameter of the protected line warnings for stiffeners whose inner contact diameter was not greater than the protected line outer contact diameter.
• Line segments could be drawn with excess length in shaded graphics. This incorrect segment extension only appeared for line segments that were both drawing slug flow and drawing contact. Only drawing is affected by this issue.

These bugs are fixed in version 11.5c.

New in version 11.5b

Bug fix

• If OrcaFlex could not find a license at startup, it would report an access violation error instead of an informative error message.

This bug is fixed in version 11.5b.

New in version 11.5a

Lines

• Buried lines can now be modelled using line covered sections. These can be used to model upheaval buckling and pipe ratcheting.
• To help support the modelling of synthetic ropes with rate-dependent stiffness, the line type axial stiffness can now accept an axial static-dynamic stiffness variable data source. This allows the axial stiffness to vary between the static and dynamic analyses, whilst ensuring the continuity of the system's equilibrium between statics and dynamics. The dynamic stiffness can be defined as a function of the static tension.
• To help with model building when pre-bend is in use, a new show pre-bend node positions button has been added to pre-bend data page. This presents a spreadsheet window showing the node positions and orientations based on the assumption that the line adopts its unstressed position as determined by the pre-bend data.
• It is now possible to use profiled line types when the length and end orientations are calculated from end positions. In this scenario the section length will be determined by the end positions rather than the profile length. If the calculated length and the profile length do not match, then the profile will be truncated.
• Line sections were previously limited to containing no more than 2,000 segments. This limit has been increased to 50,000.
• When using the spline starting shape for step 1 statics, the maximum number of spline control points has been increased to 1,000.
• Seabed resistance profiles can now have an unloading stiffness of N/A, which means that the resistance unloads elastically upon reversal of motion. It is now also possible to specify an unloading stiffness of zero.
• Seabed resistance profiles are now restarted in a different way when reloading state from a parent analysis. Previously, any change to the profile table or unloading stiffness would trigger a reset of the resistance profile's history in the restart analysis. This meant that any parent model state (the analogue of the target position for Coulomb friction) would have been discarded. The new policy is to retain this state whenever possible. The old behaviour can be recovered by explicitly marking the profile name as changed on the line data form. Manually marking the profile as changed, or using an entirely different profile, forces a complete reset of the history state before running the child analysis.
• The summary results report for lines now includes a page listing the instantaneous seabed spans. This is only included in the report if the line has some nodes on the seabed.

Turbines

• The turbine’s initial rotor angular velocity can now be specified. Applied in the static analysis, it permits the system to find a quasi-dynamic equilibrium, accounting for the steady-state loading associated with the turbine's rotation. This enables a smooth transition between statics and dynamics, and removes the need for a lengthy build-up period to simulate the rotor accelerating up to speed.
• The frame of reference that the blade degrees of freedom (DOFs) are solved in can now be nominated. Previously, the blade DOFs were always solved in the global inertial frame. Now, the blade DOFs can be solved in a non-inertial rotating frame, fixed to the turbine's hub. Although physically equivalent, the new rotating frame is a far more natural choice for a spinning rotor, allowing for simulations with improved stability and a larger time step.

Analysis

Rigid connections between objects can now be enforced indirectly, using Lagrange multiplier techiques instead of the coordinate mappings that are usually employed. Indirect rigid connections are applied using the same mathematical formulation as indirectly solved constraints. This can have performance benefits for certain models containing long chains of rigid connections.

Vessels

• Time domain panel pressure results are now available for vessels. This pressure is specific to the vessel motion seen in a time domain simulation, in contrast to the panel pressure available from diffraction software, e.g. OrcaWave, which is only relevant to the vessel motion given by displacement RAOs. The time domain pressure is obtained via the API (see the documentation for Python, Matlab, C++), which performs a post-processing calculation using (i) an OrcaFlex time domain simulation of the vessel, and (ii) an OrcaWave diffraction model of the corresponding vessel type. The pressure calculation is based on first-order wave theory and can include three distinct components (hydrostatic, diffraction, radiation), each of which correspond to a distinct vessel load (hydrostatic stiffness load, wave load, added mass and damping load, respectively).
• New results have been added for primary velocity and acceleration. These additional results are used in the post-processing calculation of time domain panel pressure.
• The standard import process for WAMIT .out files has been extended to handle results for full QTFs that are limited to a subset of periods and/or headings.
• A facility to view added mass and damping data has been added for vessel types and multibody groups. This presents the frequency dependent added mass and damping data in a single spreadsheet window which makes it possible to see the entire set of data, for all periods and frequencies, in one place.

Buoys

New wetted volume results have been added for 3D buoys and 6D buoys.

Supports

The support axes for each support in the model can now be drawn. Some support results refer to these directions. These axes are shown or hidden using the local axes preference.

Previously the support axes were not drawn, but supports could draw their cylinder axes. Drawing of support cylinder axes is now controlled by the support cylinder axes preference.

Winches

Intermediate winch connection point drawing for shaded graphics can now be disabled.

Shapes

A new type of shape, wire frame, has been added. A wire frame shape has no physical effect on the model, and is used solely for drawing purposes. The drawing is based on wire frame data, in the same manner as other objects, e.g. vessels and 6D buoys.

Environment

It is now possible to directly specify the scale for each wind velocity component when using the Mann full field wind file format.

Results

Overall load results have been removed for 6D and 3D buoys. These results were somewhat arbitrarily defined and of dubious benefit.

Frequency domain

• The frequency domain solver now supports multibody groups.
• Vessel wind load and current load results are now available.
• Data that only affects the synthesised realisation of time histories can now be changed after the frequency domain dynamic analysis has completed. Examples of such realisation data include wave and wind random seeds, wave origin, and wave and wind time origins.

External functions

Errors raised by external functions during dynamic simulations would previously lead to the simulation being reset. This could make it hard to diagnose why the errors occurred. Such scenarios now lead to the simulation being aborted rather than reset so that results prior to the error occurring can be inspected.

User interface

• Data forms can now be modal or modeless, as determined by a preference. In previous versions data forms were always modal. If data forms are modal then, while a data form is showing, you cannot interact with other parts of the user interface, e.g. view windows, model browser, etc. If data forms are modeless then you can interact with other parts of the user interface while a data form is showing. When data forms are modeless you can view multiple data forms simultaneously.
• Simple formulae can be entered into data fields using an "=" prefix. These are evaluated using the same expression evaluator available to text data files. Formulae are evaluated and then the calculated value is entered into the data field.

OrcFxAPI (OrcaFlex programming interface)

• New functions have been added to find the local extrema of a time series. These functions are: C_CreateLocalExtrema, C_DestroyLocalExtrema, C_LocalExtremaAddSamples and C_LocalExtremaGet. The new functionality is also available in the Python and MATLAB interfaces through a new function named FindLocalExtrema.
• A new function, C_GetNodeSeabedFrictionTargetPositions, has been added to retrieve the seabed friction target positions for the nodes of a line object. The new functionality is also available in the Python and MATLAB interfaces through a new property named NodeSeabedFrictionTargetPositions.
• New functions have been added to save model views in the enhanced metafile format. These functions are: C_SaveModel3DViewMetafile and C_SaveModel3DViewMetafileMem. The new functionality is also available in the Python and MATLAB interfaces through new functions named SaveModelViewMetafile and SaveModelViewMetafileMem.
• A new method named SetLayAzimuthFromEndPositions has been added to both the Python and MATLAB interfaces. This sets the line lay azimuth data to be the direction from the bottom end towards the top end, based on their current positions, replicating the identical functionality available from the GUI.

New in version 11.4e

Shear7

Support has been added for SHEAR7 version 4.12b, specifically by capturing the new curvature time history files which SHEAR7 can now export.

Python

Python external functions, post calculation actions and user defined results now support the latest version of Python, version 3.13.

Frequency domain

The frequency domain solver now supports lines using a constant expansion factor.

Bug fixes

• When loading fatigue analysis data, saved in YAML text data format, the value specified in the file for number of thetas was being ignored.
• An access violation error may have arisen when performing a restart analysis with multibody groups. This would occur if the multibody group vessel objects did not use frequency dependent added mass and damping in the parent simulation, but then frequency dependent added mass and damping was used in the restart.
• OrcaFlex's change tracking mechanism would sometimes fail to export the names of current data sets to a variation file, but only when the child model used multiple current sets and the parent model did not.
• For lines that use the analytic catenary representation, the reported vertical and effective tension results could sometimes be reported erroneously as zero, when below the minimum horizontal tension of the solution grid. This happened when the use of finite precision machine arithmetic in the extrapolation scheme resulted in very small, negative horizontal tension values. In such cases, the solution was being deemed invalid and the whole tension vector was reported with zero magnitude. In this scenario, a warning would have been displayed when the line moved out of the solution grid, and only the reported tension results would have been affected. To resolve this, only the horizontal component of tension is set to zero, and the extrapolated vertical component is retained.
• The frequency domain solver did not account for line expansion factors specified via a line type expansion table.
• Line expansion factor results could have been reported incorrectly for lines using pressure dependent expansion tables, if the pressure of the line's contents depended on its vertical position. The same was also true for lines using temperature dependent expansion tables, if the temperature of the line's contents depended on its vertical position.
• Building a model containing a combination of 6D buoy wings, time history wind and disabled statics would have a precipitated an immediate access violation error.

New in version 11.4d

Bug fixes

• Spurious tracked changes would have appeared in the depth column of the profiled seabed data table when opening a text variation or restart file.
• An access violation error may have arisen when opening a data form after loading a variation model or restart analysis from a binary data or simulation file created by version 11.1.
• End B of a prescribed statics line could never begin a dynamics only restart analysis from its calculated position at the end of the parent analysis. Normally, this state would be inherited if the end B position data were unchanged between the parent and child analyses, but this was impossible to arrange for this particular case.
• Setting integer data items using variables in a text data file would sometimes fail, with an unexpected program error.
• Exported spreadsheet files with .xlsx format could sometimes contain sheet names that were not valid Excel sheet names. These files could not be opened by Excel. Excel sheet names must be no more than 31 characters long, must not start or finish with ', and must not contain any of the following characters: / \ ? * : [ ]. Any such sheet names are now normalised before being exported, with invalid characters being replaced by the _ character.
• Dynamics only restart analyses would not run for models with winches whose statics control mode had been changed relative to the parent analysis.
• Running a line feeding model with an open range graph could sometimes result in an access violation error.
• Line feeding restarts would sometimes have failed to converge when a node was fed out in the first time step of the restart analysis.
• The default value of the vessel characteristic force (the value used when the characteristic force has been set to ~) was being calculated from the vessel type properties without correctly accounting for Froude scaling. This would only have affected vessels whose length was not ~.
• A small correction has been made to the stiffness Jacobian associated with vessel wind loading. This only affects frequency domain analysis and its influence on results is expected to be very small.
• Line solid contact force results were reported incorrectly for protected line nodes whose contact diameters are greater than that of the corresponding stiffener line node. In this scenario the solid contact force was always reported as zero, even if it was non-zero. The bug only affected the reporting of results. The solid contact forces used by the analysis were correct, even though they were reported incorrectly.
• Line seabed normal resistance and seabed normal resistance/D results did not account for the bespoke seabed contact properties of seabed sections. The bug only affected the reporting of results. The seabed contact forces used by the analysis were correct, even though they were reported incorrectly.
• In a restart analysis, connecting an existing object to a newly-added (i.e. added as part of the restart) constraint may not have worked as expected, and the existing object may have ended up in the wrong position.
• Models using expansion tables would sometimes raise an access violation error. This would happen if any line using an expansion table also used one of the following features: externally calculated applied loads, externally calculated stiffness data, stiffness external results or hysteretic bend stiffness.
• Results for restart chains, when using mid-simulation restarts, could sometimes erroneously include results for additional sample times. These additional results samples would be from the parent simulation, for times after the restart from time, and would overlap with times from the restart.

New in version 11.4c

Bug fixes

• Restarts replays with start and finish times outside the range covered by the specified simulations resulted in an access violation error.
• 6D buoy static state total load results (reported with respect to global axes) could not be obtained upon completion of a frequency domain analysis.
• OrcaFlex became progressively more unresponsive as the number of bodies in a multibody group increased.
• Spurious tracked changes could appear if new winch connections were added via a text variation file.
• Since version 11.4a, the dimensions of the model browser were not being stored and restored when OrcaFlex was closed and re-opened.
• An object's orientation may have been incorrect in a restart analysis if the parent analysis was itself a restart analysis and the object's connection parent had been changed somewhere in the chain of restarts.
• Access violation errors may have arisen when modifying variation models or restart analyses loaded from binary data or simulation files. This bug would only have affected models containing lines or winches.
• At replay times within the simulation, OrcaFlex would show N/A when presenting instantaneous value tables for user defined results, irrespective of the values returned by the user defined result code.
• Connecting a newly created object, added in a restart analysis, to a line node that had been fed out in the course of the parent analysis (but which was inactive in the restart model's reset state) would have resulted in the object being connected to the wrong node during the analysis.

New in version 11.4b

OrcFxAPI (OrcaFlex programming interface)

The API has been extended to allow cloning of multiple objects with the addition of the C_CreateClone3 function. This functionality is available for Python and MATLAB through the new model function CreateClones. The new functionality provides support for cloning multiple objects in a single operation, whilst respecting any connections within the collection of objects being cloned. Additionally, the new functionality can clone groups.

Bug fixes

• The variable list on the results form was being truncated on its right hand side, so hiding the list's vertical scroll bar.
• Pasting or duplicating (e.g. copy down with CTRL+D) in the line user specified starting shape table was resulting in an assertion failure error.
• Printing internal spreadsheet windows failed with an access violation error.
• It was not possible to reload simulation files containing a combination of Rayleigh damped lines and constraints solved with the indirect solution method.
• Change tracking for winch connections might not have worked correctly if rows were inserted into or deleted from the winch connections table and some of the connection parent objects were changed.
• Viewing position data for label shapes in the connections view of the all objects data form would have led to an unexpected program error.
• The example code for restart state recording test failed with an error stating that Period.PeriodNum of pnInstantaneousValue is not allowed. In previous versions of OrcaFlex this period could only be used in code from an external function. This restriction has now been lifted so that the example code can be used. This restriction was not present in our in-house builds to facilitate certain testing scenarios, which is why we did not discover the issue during development.
• The OrcaFlex spreadsheet could not find local files when working in a folder that is synchronised to a personal OneDrive account. Business OneDrive folders were not affected by this issue. Both types of OneDrive account now work correctly.

These bugs are fixed in version 11.4b.