Flexcom 2025.1.3 |
 
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Flexcom 2025.1.3 |
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The following faults are present in Flexcom 2025.1.3. More detailed information on each fault is provided in the following sections.
No |
Issue |
Severity |
1 |
Hydrodynamic Data Importer fails to read OrcaWave file |
Minor |
2 |
Model view doesn't work in Flexcom Demo version |
Minor |
3 |
Flexcom may crash when run from the command line on machines with large number of logical processors |
Minor |
4 |
Hydrodynamic Data Importer incorrectly applying scale factor to OrcaWave radiation damping terms |
Minor |
5 |
Floating body viscous drag loads, computed with absolute velocity, are not rotated to global axis system |
Minor |
6 |
Initial blade pitch angle coming from ServoDyn is incorrect |
Minor |
7 |
Floating body added mass always applied at centre of gravity |
Major |
8 |
Aerodynamic forces on wind turbine blade applied at structural centre rather than aerodynamic centre |
Major |
•Related Topics: Hydrodynamic Data Importer
•Description: The format of the Hydrostatics tab of the Excel file has been updated in recent versions of OrcaWave, making it incompatible with the data reading routines of the Hydrodynamic Data Importer.
•Workaround: Use an older version of OrcaWave (e.g. 11.2). Alternatively, contact us for assistance, we can supply you with a new edition of the HDI tool.
•Related Topics: Model View
•Description: Flexcom's model view appears blank in the demo version of the software. The issue was caused by an incorrect DLL being loaded into the installer pack by the automated scripts on our builds server machine. Usage of the demo version is limited so this is unlikely to inconvenience many Flexcom users.
•Workaround: Copy the file called MCSDYNDISP.DLL from a full installation of Flexcom 2025.1.3, and paste it into the installation folder of the Demo version.
•Related Topics: Network Licensing Client
•Description: The Network License Client includes code to enumerate the CPU on the local machine hosting Flexcom. One section of code requires a large array, which is dimensioned on the heap rather than the stack. Where a large number of CPUs are present, the code fails to allocate sufficient memory, and the program crashes.
•Workaround: Contact us for assistance if you encounter this issue, we can supply you with a new edition of the license DLL.
•Related Topics: Hydrodynamic Data Importer
•Description: Flexcom incorrectly applies a radian-to-degree scaling factor on the radiation damping terms which include a rotational dependency (i.e. the matrix entries in Radiation Damping Coefficients which contain an "ω" symbol).
•Workaround: Manually remove the scale factor from the radiation damping coefficient file generated by the HDI tool (i.e. the file entitled "Radiation_Damping.incx"). Alternatively, contact us for assistance, we can supply you with a new edition of the HDI tool.
•Related Topics: Viscous Damping Loads
•Description: Viscous drag loads are computed in the local body axis system (surge, sway etc.) before being transferred into the global axis system prior to solution. The absolute (floating body velocity only) and the relative options (relative velocity between floating body and external fluid) are implemented in separate routines, and the former procedure unintentionally omits the local to global transformation. This can lead to incorrect application of drag forces, particularly if the local surge axis deviates significantly from the global Y axis.
•Workaround: Use the relative velocity option instead (*VISCOUS DRAG -> OPTION=RELATIVE).
•Related Topics: ServoDyn
•Description: This bug relates to the source code for OpenFAST rather then Flexcom. In the initialisation routines, the blade pitch returned from the controller is converted from degrees to radians in ServoDyn, even though it is already in radians when provided by the controller. The issue only affects initial blade pitch, and all other values during the simulation are correct.
•Workaround: None, but the incorrect value is momentary, so it does not have any significant impact on the overall results.
•Related Topics: Floating Body
•Description: All previous versions of Flexcom have placed the floating body added mass at the body centre of mass. This approach is incorrect, as the added mass relates to fluid mass rather than structural mass. In all versions post-Flexcom 2025.1.3, the added mass is applied at the reference point by default. It is also possible to select a different location, such as the centre of buoyancy if you wish.
•Workaround: None. There is no workaround, so you are advised to upgrade to Flexcom 2026.1.1 or later.
•Related Topics: Wind Turbine Modelling
•Description: The application of aerodynamic forces and moments in the flexible blade model are not taking into account the spatial offset between the structural centre and the aerodynamic centre on the blade cross section. A similar limitation applies to the application of mass terms at the centre of gravity, although this is likely to be less significant. So, although the blade structural properties are correctly represented by the relevant stiffness terms, the twisting moment induced by the spatial offset is neglected. This could lead to some inaccuracy in deformational blade twist induced by the wind loads, particularly near rated wind speed where the forces are largest. Notwithstanding this limitation, the structural twist due the physical shape of the blade, and the rigid body twist imparted by the control system, are both correct. As these terms account for the majority of the overall twist angle, the local angle of attack and the corresponding aerodynamic forces should be quite close to their theoretical values.
•Workaround: There is no workaround, so you are advised to upgrade to Flexcom 2026.1.1 or later.