Dear Jason
Thank you for your prompt response. I am quite certain that I am currently using version 3.5.1 of FAST.farm. The wind turbines I am using are the OC4 semi-submersible platform turbines, and all parameters are kept at their default values. However, I am using the default IW.dat file from FAST.farmās TSinflow for the InflowFile, and for simplicity, I have set WindType to 1 and wind speed to 6 m/s.
Regarding the input files for FAST.farm, they are as follows:
--- SIMULATION CONTROL ---
False Echo - Echo input data to <RootName>.ech? (flag)
FATAL AbortLevel - Error level when simulation should abort (string) {"WARNING", "SEVERE", "FATAL"}
3000.0 TMax - Total run time (s) [>=0.0]
False UseSC - Use a super controller? (flag)
3 Mod_AmbWind - Ambient wind model (-) (switch) {1: high-fidelity precursor in VTK format, 2: one InflowWind module, 3: multiple instances of InflowWind module}
1 Mod_WaveField - Wave field handling (-) (switch) {1: use individual HydroDyn inputs without adjustment, 2: adjust wave phases based on turbine offsets from farm origin}
0 Mod_SharedMooring - Shared mooring system model (switch) {0: None, 3=MoorDyn}}
--- SUPER CONTROLLER --- [used only for UseSC=True]
"unused" SC_FileName - Name/location of the dynamic library {.dll [Windows] or .so [Linux]} containing the Super Controller algorithms (quoated string)
--- SHARED MOORING SYSTEM --- [used only for Mod_SharedMoor>0]
"" SharedMoorFile - Name of file containing shared mooring system input parameters (quoted string) [used only when Mod_SharedMooring > 0]
0.04 DT_Mooring - Time step for farm-level mooring coupling with each turbine (s) [used only when Mod_SharedMooring > 0]
--- AMBIENT WIND: PRECURSOR IN VTK FORMAT --- [used only for Mod_AmbWind=1]
3.0 DT_Low-VTK - Time step for low -resolution wind data input files; will be used as the global FAST.Farm time step (s) [>0.0]
0.1 DT_High-VTK - Time step for high-resolution wind data input files (s) [>0.0]
"unused" WindFilePath - Path name to VTK wind data files from precursor (string)
False ChkWndFiles - Check all the ambient wind files for data consistency? (flag)
--- AMBIENT WIND: INFLOWWIND MODULE --- [used only for Mod_AmbWind=2 or 3]
3.0 DT_Low - Time step for low -resolution wind data interpolation; will be used as the global FAST.Farm time step (s) [>0.0]
0.1 DT_High - Time step for high-resolution wind data interpolation (s) [>0.0]
300 NX_Low - Number of low -resolution spatial nodes in X direction for wind data interpolation (-) [>=2]
81 NY_Low - Number of low -resolution spatial nodes in Y direction for wind data interpolation (-) [>=2]
30 NZ_Low - Number of low -resolution spatial nodes in Z direction for wind data interpolation (-) [>=2]
-100 X0_Low - Origin of low -resolution spatial nodes in X direction for wind data interpolation (m)
-400.0 Y0_Low - Origin of low -resolution spatial nodes in Y direction for wind data interpolation (m)
5.0 Z0_Low - Origin of low -resolution spatial nodes in Z direction for wind data interpolation (m)
10.17 dX_Low - Spacing of low -resolution spatial nodes in X direction for wind data interpolation (m) [>0.0]
10.0 dY_Low - Spacing of low -resolution spatial nodes in Y direction for wind data interpolation (m) [>0.0]
10.0 dZ_Low - Spacing of low -resolution spatial nodes in Z direction for wind data interpolation (m) [>0.0]
32 NX_High - Number of high-resolution spatial nodes in X direction for wind data interpolation (-) [>=2]
16 NY_High - Number of high-resolution spatial nodes in Y direction for wind data interpolation (-) [>=2]
16 NZ_High - Number of high-resolution spatial nodes in Z direction for wind data interpolation (-) [>=2]
"turbines/IW.dat" InflowFile - Name of file containing InflowWind module input parameters (quoted string)
--- WIND TURBINES ---
2 NumTurbines - Number of wind turbines (-) [>=1] [last 6 columns below used only for Mod_AmbWind=2 or 3]
WT_X WT_Y WT_Z WT_FASTInFile X0_High Y0_High Z0_High dX_High dY_High dZ_High
(m) (m) (m) (string) (m) (m) (m) (m) (m) (m)
0.0 30.0 0.0 "turbines/5MW_OC4Semi_WSt_WavesWN1.fst" -69.49 -50.0 5.0 10.17 10.0 10.0
1008 0.0 0.0 "turbines/5MW_OC4Semi_WSt_WavesWN2.fst" 938.00 -80.0 5.0 10.17 10.0 10.0
After I modified the spacing of the two semi-submersible fans, the current example can be successfully calculated after 3000s, but the following error occurs
T2:FARM_UpdateStates:FWrap_Increment:FAST_Solution:CalcOutputs_And_SolveForInputs:SolveOption2:AD_CalcOutput:RotCalcOutput:BEMT_CalcOutput(node 5, blade
1):UA_CalcOutput:UA_BlendSteady:Temporarily turning off UA due to high angle of attack or low
relative velocity. This warning will not be repeated though the condition may persist.
The BEM solution is being turned off due to low TSR. (TSR = 1.9989). This warning will not be repeated.
FARM_CalcOutput:AWAE_CalcOutput:LowResGridCalcOutput:The center of wake plane #131 for turbine #2 has passed the upper-most X boundary of the low-resolution domain.ļ¼In fact several wake planes have experienced this problemļ¼
I would like to ask another question, which is related to calculating the wake of wind turbines. Typically, in high-fidelity simulations, there should be more high-resolution grid points downstream of the wind turbine compared to upstream. However, in the default cases provided by the official documentation, for the first wind turbine, the starting point of the high-resolution grid (in the x-direction) is -70m, the grid length is 5m, and the default number of grid points is 16. This means that the high-resolution grid spans from -70m to 10m. Since the wind turbine is located at 0m, does it mean that this high-resolution grid only captures the wake of the turbine from 0m to 10m downstream? Thi