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OpenFAST / openfast

Main repository for the NREL-supported OpenFAST whole-turbine and FAST.Farm wind farm simulation codes.
http://openfast.readthedocs.io
Apache License 2.0
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Wind - wave misalignment #1964

Open sffgd opened 8 months ago

sffgd commented 8 months ago

hello， I want to simulate different wind and wave conditions, here's what I modeled： ①Change the direction of the wave,In the HydroDyn file I set DiffQTF=0,Further,set WaveDir=30°； ②Change the direction of the incoming wind,In the turbsim file I set HFlowAng=8°. I don't know if this setting is correct, I hope you can correct it！

Best regard！

jjonkman commented 8 months ago

Dear @sffgd,

I agree that setting WaveDir in HydroDyn will change the wave propagation direction. You shouldn't need to set DiffQTF to change the wave direction unless your QTF data is not defined for the wave direction of interest.

We generally recommend to change the TurbSim wind direction via InflowWind input PropagationDir rather than by using a nonzero HFlowAng in TurbSim.

Best regards,

sffgd commented 3 months ago

Dear @jjonkman, If I want to set yaw error angles in openfast, can I do that by setting inflowWind-PropagationDir?. The introduction to PropagationDir says the rotation angle is specified as a meterorological rotation angle about the Z-axis(rotation from alignment with positive X towards negative Y) and the figure shown below is correct? ![Uploading 7777.png…]()

jjonkman commented 3 months ago

Dear @sffgd,

I agree with your description of input PropagationDir within InflowWind, but your figure is not showing up (at least I can't see it).

Best regards,

sffgd commented 3 months ago

Dear @jjonkman, Thank you for your reply, there seems to be a problem with uploading pictures. Here is another way to indirectly change the wind direction to form yaw error. Is this correct? Can I keep the incident wind direction at 0°, set NacYaw=15° in ServoDyn and keep the cabin degree of freedom enabled (YawDOF=Ture), and set the neutral yaw position at 15° (YawNeut=15°)

Best regards,

sffgd commented 3 months ago

Dear @jjonkman, When the idle state of the 15MW wind turbine is shut down (idle state setting is complete), the wind speed is set to 45m/s and the turbulence intensity is 13.3%. When the wind direction is set to 15°, using the above two methods to simulate, I received the following error: FAST_Solution:FAST_AdvanceStates:SolveOption2c_Inp2AD_SrvD:InflowWind_CalcOutput:CalculateOutput:I fW_FlowField_GetVelAcc:Grid3DField_GetCell: GF wind array boundaries violated: Grid too small in Y direction. Y=-141.02; Y boundaries = [-141, 141]

OpenFAST encountered an error at simulation time 73.05 of 4600 seconds. Simulation error level: FATAL ERROR

You mentioned disabling edge degrees of freedom (EdgeDOF=False) or increasing blade edge damping (BldEdDmp(1)), then I set EdgeDOF=False and still got an error. But I do not know how to set up to increase blade edge damping, hope to get help. Thank you!

Best regards,

jjonkman commented 3 months ago

Dear @sffgd,

Here is another way to indirectly change the wind direction to form yaw error. Is this correct? Can I keep the incident wind direction at 0°, set NacYaw=15° in ServoDyn and keep the cabin degree of freedom enabled (YawDOF=Ture), and set the neutral yaw position at 15° (YawNeut=15°)

Yes, I agree.

If disabling the blade edgewise DOF does not eliminate the error, increasing blade edgewise damping wont either.

Are you receiving a warning about large blade deflection before receiving this error? Or is it just that your wind domain is too small considering the 15-deg yaw error you imposed such that a slight increase to the domain size will eliminate the error?

Best regards,

sffgd commented 3 months ago

Dear @jjonkman, First of all, I don't receiving a warning about large blade deflection before receiving this error(Full error message below). Secondly, The turbulent wind field was generated using the TurbSim with a grid size of 282 × 282 m and 961 grid points (31 × 31), while the diameter of IEA 15MW semi-submersible FOWT's wind wheel is 240m. Or maybe it's not because the wind field is too small？（I once again using the TurbSim with a grid size of 285 × 285 m and 961 grid points (31 × 31)，use this to check if there are still errors）

Best regards,

（OpenFAST-v3.5.1 Compile Info:

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

Running ElastoDyn. Running AeroDyn. Running InflowWind.

Reading a 31x31 grid (282 m wide, 9 m to 291 m above ground) with a characteristic wind speed of 45.88 m/s. This full-field file was generated by TurbSim (v2.00.07a-bjj, 14-Jun-2016) on 24-Apr-2024 at 22:22:36.

Processed 368000 time steps of 80-Hz grid-field data (period of 4600 seconds). 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. Reading in WAMIT output with root name ".\HydroData/IEA-15-240-RWT-UMaineSemi". Computing radiation impulse response functions and wave diffraction forces. Running MoorDyn (v2.0.0, 2023-09-18). This is MoorDyn v2, with significant input file changes from v1. Copyright: (C) 2023 National Renewable Energy Laboratory, (C) 2019 Matt Hall Parsing MoorDyn input file: .\IEA-15-240-RWT-UMaineSemi_MoorDyn.dat Warning: invalid output specifier CON1FX. Must start with L, C, R, or B Warning: invalid output specifier CON3FX. Must start with L, C, R, or B Warning: invalid output specifier CON5FX. Must start with L, C, R, or B Warning: invalid output specifier CON1FY. Must start with L, C, R, or B Warning: invalid output specifier CON3FY. Must start with L, C, R, or B Warning: invalid output specifier CON5FY. Must start with L, C, R, or B Warning: invalid output specifier CON1FZ. Must start with L, C, R, or B Warning: invalid output specifier CON3FZ. Must start with L, C, R, or B Warning: invalid output specifier CON5FZ. Must start with L, C, R, or B Warning: invalid output specifier CON2FX. Must start with L, C, R, or B Warning: invalid output specifier CON4FX. Must start with L, C, R, or B Warning: invalid output specifier CON6FX. Must start with L, C, R, or B Warning: invalid output specifier CON2FY. Must start with L, C, R, or B Warning: invalid output specifier CON4FY. Must start with L, C, R, or B Warning: invalid output specifier CON6FY. Must start with L, C, R, or B Warning: invalid output specifier CON2FZ. Must start with L, C, R, or B Warning: invalid output specifier CON4FZ. Must start with L, C, R, or B Warning: invalid output specifier CON6FZ. Must start with L, C, R, or B Warning: invalid output specifier FX. Object ID missing. Warning: invalid output specifier FY. Object ID missing. Warning: invalid output specifier FZ. Object ID missing. Created mooring system: 3 lines, 6 points, 0 rods, 0 bodies. Finalizing initial conditions using dynamic relaxation. t=36.1 FairTen 1: 2.43899E+06, 2.43984E+06, 2.44053E+06

Fairlead tensions converged to 0.1% after 36.1 seconds. Fairlead tension: 2.43899E+06 Fairlead forces: -1.35268E+06, 0, -2.02951E+06 Fairlead tension: 2.43902E+06 Fairlead forces: 6.76355E+05, 1.17148E+06, -2.02953E+06 Fairlead tension: 2.43902E+06 Fairlead forces: 6.76355E+05, -1.17148E+06, -2.02953E+06 MoorDyn initialization completed. Running ServoDyn.

FAST_InitializeAll:HydroDyn_Init:HydroDynInput_ProcessInitData: A requested output channel is invalid

Time: 70 of 4600 seconds. Estimated final completion at 10:17:07.

FAST_Solution:FAST_AdvanceStates:SolveOption2c_Inp2AD_SrvD:InflowWind_CalcOutput:CalculateOutput:I fW_FlowField_GetVelAcc:Grid3DField_GetCell: GF wind array boundaries violated: Grid too small in Y direction. Y=-141.02; Y boundaries = [-141, 141]

OpenFAST encountered an error at simulation time 73.05 of 4600 seconds. Simulation error level: FATAL ERROR

Aborting OpenFAST. ）

jjonkman commented 3 months ago

Dear @sffgd,

Given the combination of yaw error, blade deflection, and floater motion, I would guess that an aerodynamic analysis node is leaving the TurbSim wind domain such that increasing the width of the domain will solve the issue.

Best regards,