Bug report

[Stephen-cby]

Bug description
Issue with visualization of IEA-15-240-RWT-UMaineSemi
To Reproduce
Steps to reproduce the behavior:

1. I am using OpenFAST v3.3.0 from https://github.com/OpenFAST/openfast/releases/download/v3.3.0/openfast_x64.exe
2. I am running IEA-15-240-RWT-UMaineSemi case from https://github.com/IEAWindTask37/IEA-15-240-RWT/archive/refs/tags/v1.1.3.zip
3. I want to get the visualization of this case and set WrVTK=2; VTK_type=1 in the input file.
4. However, the error occurs:

---

OpenFAST-Unversioned from 5f3fb6e
Compile Info:

• Compiler: Intel(R) Fortran Compiler 2021
• Architecture: 64 bit
• Precision: single
• OpenMP: No
• Date: Mar 08 2023
• Time: 16:38:05
  Execution Info:
• Date: 03/08/2023
• Time: 20:29:10+0800

OpenFAST input file heading:
IEA 15 MW offshore reference model on UMaine VolturnUS-S semi-submersible floating platform

Running ElastoDyn.
Running AeroDyn.
Warning: Turning off Unsteady Aerodynamics because UA parameters are not included in airfoil
(airfoil has likely has constant polars). (node 1, blade 1)
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. (node 2, blade 1)
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. (node 4, blade 1)
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. (node 5, blade 1)
Warning: Turning off Unsteady Aerodynamics because UA parameters are not included in airfoil
(airfoil has likely has constant polars). (node 1, blade 2)
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. (node 2, blade 2)
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. (node 4, blade 2)
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. (node 5, blade 2)
Warning: Turning off Unsteady Aerodynamics because UA parameters are not included in airfoil
(airfoil has likely has constant polars). (node 1, blade 3)
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. (node 2, blade 3)
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. (node 4, blade 3)
Warning: Turning off Unsteady Aerodynamics because C_nalpha is 0. (node 5, blade 3)
Running InflowWind.
Running HydroDyn.
WARNING: The requested output channel is invalid: WavesF1xi
WARNING: The requested output channel is invalid: WavesF1zi
WARNING: The requested output channel is invalid: WavesM1yi
WARNING: The requested output channel is invalid: WavesF2xi
WARNING: The requested output channel is invalid: WavesF2zi
WARNING: The requested output channel is invalid: WavesM2yi
WARNING: The requested output channel is invalid: WavesF2xi
WARNING: The requested output channel is invalid: WavesF2yi
WARNING: The requested output channel is invalid: WavesF2zi
WARNING: The requested output channel is invalid: WavesM2xi
WARNING: The requested output channel is invalid: WavesM2yi
WARNING: The requested output channel is invalid: WavesM2zi
Generating incident wave kinematics and current time history.
Calculating second order difference frequency wave kinematics.
Calculating second order sum frequency wave kinematics.

FAST_InitializeAll:FAST_Init:FAST_ReadPrimaryFile:1/VTK_fps is not an integer multiple of DT.
FAST will output VTK information at 13.333 fps, the closest rate possible.
FAST_InitializeAll:HydroDyn_Init:HydroDynInput_ProcessInitData: A requested output channel is
invalid
HydroDyn_Init: WaveElevSeries arrays for first and second order wave elevations are of different
sizes.

OpenFAST encountered an error during module initialization.
Simulation error level: FATAL ERROR

Aborting OpenFAST.

Expected behavior
I want to get some surface vtk file of this case.
VISUALIZATION code of input file
---------------------- VISUALIZATION ------------------------------------------
2 WrVTK - VTK visualization data output: (switch) {0=none; 1=initialization data only; 2=animation}
1 VTK_type - Type of VTK visualization data: (switch) {1=surfaces; 2=basic meshes (lines/points); 3=all meshes (debug)} [unused if WrVTK=0]
False VTK_fields - Write mesh fields to VTK data files? (flag) {true/false} [unused if WrVTK=0]
15.0 VTK_fps - Frame rate for VTK output (frames per second){will use closest integer multiple of DT} [used only if WrVTK=2]

OpenFAST Version
OpenFAST v3.3.0

[Stephen-cby]

WAVES code of HydroDyn file
---------------------- WAVES ---------------------------------------------------
2 WaveMod - Incident wave kinematics model {0: none=still water, 1: regular (periodic), 1P#: regular with user-specified phase, 2: JONSWAP/Pierson-Moskowitz spectrum (irregular), 3: White noise spectrum (irregular), 4: user-defined spectrum from routine UserWaveSpctrm (irregular), 5: Externally generated wave-elevation time series, 6: Externally generated full wave-kinematics time series [option 6 is invalid for PotMod/=0]} (switch)
0 WaveStMod - Model for stretching incident wave kinematics to instantaneous free surface {0: none=no stretching, 1: vertical stretching, 2: extrapolation stretching, 3: Wheeler stretching} (switch) [unused when WaveMod=0 or when PotMod/=0]
850.00 WaveTMax - Analysis time for incident wave calculations (sec) [unused when WaveMod=0; determines WaveDOmega=2Pi/WaveTMax in the IFFT]
0.25 WaveDT - Time step for incident wave calculations (sec) [unused when WaveMod=0; 0.1<=WaveDT<=1.0 recommended; determines WaveOmegaMax=Pi/WaveDT in the IFFT]
1.10 WaveHs - Significant wave height of incident waves (meters) [used only when WaveMod=1 or 2]
8.52 WaveTp - Peak spectral period of incident waves (sec) [used only when WaveMod=1 or 2]
DEFAULT WavePkShp - Peak-shape parameter of incident wave spectrum (-) or DEFAULT (string) [used only when WaveMod=2; use 1.0 for Pierson-Moskowitz]
0.111527 WvLowCOff - Low cut-off frequency or lower frequency limit of the wave spectrum beyond which the wave spectrum is zeroed (rad/s) [unused when WaveMod=0, 1, or 6]
3.2 WvHiCOff - High cut-off frequency or upper frequency limit of the wave spectrum beyond which the wave spectrum is zeroed (rad/s) [unused when WaveMod=0, 1, or 6]
0.00 WaveDir - Incident wave propagation heading direction (degrees) [unused when WaveMod=0 or 6]
0 WaveDirMod - Directional spreading function {0: none, 1: COS2S} (-) [only used when WaveMod=2,3, or 4]
1 WaveDirSpread - Wave direction spreading coefficient ( > 0 ) (-) [only used when WaveMod=2,3, or 4 and WaveDirMod=1]
1 WaveNDir - Number of wave directions (-) [only used when WaveMod=2,3, or 4 and WaveDirMod=1; odd number only]
90 WaveDirRange - Range of wave directions (full range: WaveDir +/- 1/2*WaveDirRange) (degrees) [only used when WaveMod=2,3,or 4 and WaveDirMod=1]
-561580799 WaveSeed(1) - First random seed of incident waves [-2147483648 to 2147483647] (-) [unused when WaveMod=0, 5, or 6]
RANLUX WaveSeed(2) - Second random seed of incident waves [-2147483648 to 2147483647] (-) [unused when WaveMod=0, 5, or 6]
TRUE WaveNDAmp - Flag for normally distributed amplitudes (flag) [only used when WaveMod=2, 3, or 4]
"none" WvKinFile - Root name of externally generated wave data file(s) (quoted string) [used only when WaveMod=5 or 6]
1 NWaveElev - Number of points where the incident wave elevations can be computed (-) [maximum of 9 output locations]
0 WaveElevxi - List of xi-coordinates for points where the incident wave elevations can be output (meters) [NWaveElev points, separated by commas or white space; usused if NWaveElev = 0]
0 WaveElevyi - List of yi-coordinates for points where the incident wave elevations can be output (meters) [NWaveElev points, separated by commas or white space; usused if NWaveElev = 0]

[andrew-platt]

I can confirm this issue exists with this model and OpenFAST 3.5.0.

This issue can also be replicated using OpenFAST 3.5.0 and the 5MW_OC4Semi_WSt_WavesNW model by setting WvDiffQTF or WvSumQTF to true in the 2nd-order waves section of the HydroDyn input file and also setting the VTK outputs as above.

Short term workaround
One workaround for the moment is to turn off WvDiffQTF and WvSumQTF while running the visualization. This will affect the results a small amount, but will not likely lead to sufficient differences in motion to be noticeable in the visualization.

Long term solution
I am working on an update that will be included in release 3.5.1

[andrew-platt]

@Stephen-cby, if you need this fix in version 3.3.0, you can apply the fix from commit 736cd50d8 to your code and build from source. Otherwise, this fix will be included in v3.5.1 later this month.

[Stephen-cby]

@andrew-platt Thanks for your help. I appreciate it.