Creating u, v, and w files using TurbSim

Wind & Water Inflow Turbulence
1

Hello everyone.

I use TurbSim (can download from here https://github.com/OpenFAST/openfast/releases/tag/v4.1.2) to create wind condition files that I use when running simulations with the ModAmbient=3 setting in FAST.Farm.

I configured the inp file as follows to check the wind condition file data, and set it so that u, v, and w files would be output.

--------TurbSim v2.00.* Input File------------------------
for                    Certification - Test #1 (Kaimal Spectrum, formatted FF files).
---------Runtime Options-----------------------------------
False                  Echo        - Echo input data to <RootName>.ech (flag)
2318573                RandSeed1   - First random seed (-2147483648 to 2147483647)
RanLux                 RandSeed2   - Second random seed (-2147483648 to 2147483647) for intrinsic pRNG, or an alternative pRNG: "RanLux" or "RNSNLW"
False                  WrBHHTP     - Output hub-height turbulence parameters in binary form? (Generates RootName.bin)
False                  WrFHHTP     - Output hub-height turbulence parameters in formatted form? (Generates RootName.dat)
False                  WrADHH      - Output hub-height time-series data in AeroDyn form? (Generates RootName.hh)
True                   WrADFF      - Output full-field time-series data in TurbSim/AeroDyn form? (Generates RootName.bts)
False                  WrBLFF      - Output full-field time-series data in BLADED/AeroDyn form? (Generates RootName.wnd)
False                  WrADTWR     - Output tower time-series data? (Generates RootName.twr)
True                   WrFMTFF     - Output full-field time-series data in formatted (readable) form? (Generates RootName.u, RootName.v, RootName.w)
False                  WrACT       - Output coherent turbulence time steps in AeroDyn form? (Generates RootName.cts)
True                   Clockwise   - Clockwise rotation looking downwind? (used only for full-field binary files - not necessary for AeroDyn)
0                      ScaleIEC    - Scale IEC turbulence models to exact target standard deviation? [0=no additional scaling; 1=use hub scale uniformly; 2=use individual scales]

When I set WrFMTFF to True, I thought that u, v, and w files would be created, but in fact, three bin files were created, and their contents were garbled and could not be viewed.

image
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Is there a way to create u files, v files, and w files that allow us to check the contents instead of bin files?

2

Dear @Yuki.Ogura,

It looks like your TurbSim input file is not formatted properly. While it looks like you set WrFMTFF = TRUE on line 13, the last 5 lines in the RUNTIMES OPTIONS section are actually:

False WrADTWR - Output tower time-series data? (Generates RootName.twr)
True WrHAWCFF - Output full-field time-series data in HAWC form? (Generates RootName-u.bin, RootName-v.bin, RootName-w.bin, RootName.hawc)
False WrFMTFF - Output full-field time-series data in formatted (readable) form? (Generates RootName.u, RootName.v, RootName.w)
True WrACT - Output coherent turbulence time steps in AeroDyn form? (Generates RootName.cts)
0 ScaleIEC - Scale IEC turbulence models to exact target standard deviation? [0=no additional scaling; 1=use hub scale uniformly; 2=use individual scales]

So, you’ve actually set WrHAWCFF to TRUE instead of WrFMTFF. HAWC wind data files are binary formatted. If you want these in human readable format, you can set WrFMTFF to TRUE (on line 14).

That said, you can also read binary-formatted files (whether HAWC format or TurbSim format) into MATLAB or Python through scripts provided in the MATLAB or OpenFAST (Python) Toolboxes.

Best regards,

3

Dear @Jason.Jonkman ,[

Thank you for your reply.

I used inp file included in the OpenFAST-toolbox, but it seems I need to use the INP file available for download from this site ( 4.17.2. Appendix — OpenFAST v4.1.2 documentation ).

One more question. I created turbulent variable wind conditions for FAST.Farm using the OpenFAST-toolbox. When I checked the high-resolution wind condition file generated by TurbModel in TIMESR, it looked like the blue line in the figure. When comparing this wind profile (blue line) to one created with TurbModel set to IECKAI (black line), without changing conditions like wind speed or turbulence intensity, it appears to lack sufficient high-frequency oscillations. Can the validity of FAST.Farm simulation results be ensured using wind profiles created with the toolbox?

2
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4

Dear @Yuki.Ogura,

Can you clarify where you obtained the outdated TurbSim input file in the OpenFAST toolbox?

Can you share the TurbSim input and output files you are using for the low- and high-resolution domains?

Best regards,

5

Dear @Jason.Jonkman ,

I apologize for not providing sufficient information.

I obtained TurbSim input file from here. (GitHub - OpenFAST/openfast_toolbox: Miscellaneous Python tools for OpenFAST)

The files I used are saved in this path.

./openfast_toolbox/fastfarm/examples/SampleFiles

The TurbSim input file I used for low is

--------TurbSim v2.00.* Input File------------------------
for                    Certification - Test #1 (Kaimal Spectrum, formatted FF files).
---------Runtime Options-----------------------------------
False                  Echo        - Echo input data to <RootName>.ech (flag)
2318573                RandSeed1   - First random seed (-2147483648 to 2147483647)
RanLux                 RandSeed2   - Second random seed (-2147483648 to 2147483647) for intrinsic pRNG, or an alternative pRNG: "RanLux" or "RNSNLW"
False                  WrBHHTP     - Output hub-height turbulence parameters in binary form? (Generates RootName.bin)
False                  WrFHHTP     - Output hub-height turbulence parameters in formatted form? (Generates RootName.dat)
False                  WrADHH      - Output hub-height time-series data in AeroDyn form? (Generates RootName.hh)
True                   WrADFF      - Output full-field time-series data in TurbSim/AeroDyn form? (Generates RootName.bts)
False                  WrBLFF      - Output full-field time-series data in BLADED/AeroDyn form? (Generates RootName.wnd)
False                  WrADTWR     - Output tower time-series data? (Generates RootName.twr)
True                   WrFMTFF     - Output full-field time-series data in formatted (readable) form? (Generates RootName.u, RootName.v, RootName.w)
False                  WrACT       - Output coherent turbulence time steps in AeroDyn form? (Generates RootName.cts)
True                   Clockwise   - Clockwise rotation looking downwind? (used only for full-field binary files - not necessary for AeroDyn)
0                      ScaleIEC    - Scale IEC turbulence models to exact target standard deviation? [0=no additional scaling; 1=use hub scale uniformly; 2=use individual scales]

--------Turbine/Model Specifications-----------------------
27                     NumGrid_Z   - Vertical grid-point matrix dimension
61                     NumGrid_Y   - Horizontal grid-point matrix dimension
4.8                    TimeStep    - Time step [seconds]
4504.8                 AnalysisTime - Length of analysis time series [seconds] (program will add time if necessary: AnalysisTime = MAX(AnalysisTime, UsableTime+GridWidth/MeanHHWS) )
"ALL"                  UsableTime  - Usable length of output time series [seconds] (program will add GridWidth/MeanHHWS seconds unless UsableTime is "ALL")
313.0                  HubHt       - Hub height [m] (should be > 0.5*GridHeight)
624.0                  GridHeight  - Grid height [m]
1440.0                 GridWidth   - Grid width [m] (should be >= 2*(RotorRadius+ShaftLength))
0                      VFlowAng    - Vertical mean flow (uptilt) angle [degrees]
0                      HFlowAng    - Horizontal mean flow (skew) angle [degrees]

--------Meteorological Boundary Conditions-------------------
"IECKAI"               TurbModel   - Turbulence model ("IECKAI","IECVKM","GP_LLJ","NWTCUP","SMOOTH","WF_UPW","WF_07D","WF_14D","TIDAL","API","IECKAI","TIMESR", or "NONE")
"unused"               UserFile    - Name of the file that contains inputs for user-defined spectra or time series inputs (used only for "IECKAI" and "TIMESR" models)
1                      IECstandard - Number of IEC 61400-x standard (x=1,2, or 3 with optional 61400-1 edition number (i.e. "1-Ed2") )
"6.100 "               IECturbc    - IEC turbulence characteristic ("A", "B", "C" or the turbulence intensity in percent) ("KHTEST" option with NWTCUP model, not used for other models)
"NTM"                  IEC_WindType - IEC turbulence type ("NTM"=normal, "xETM"=extreme turbulence, "xEWM1"=extreme 1-year wind, "xEWM50"=extreme 50-year wind, where x=wind turbine class 1, 2, or 3)
"default"              ETMc        - IEC Extreme Turbulence Model "c" parameter [m/s]
"PL"                   WindProfileType - Velocity profile type ("LOG";"PL"=power law;"JET";"H2L"=Log law for TIDAL model;"API";"PL";"TS";"IEC"=PL on rotor disk, LOG elsewhere; or "default")
"unused"               ProfileFile - Name of the file that contains input profiles for WindProfileType="USR" and/or TurbModel="USRVKM" [-]
150.0                  RefHt       - Height of the reference velocity (URef) [m]
9.0                    URef        - Mean (total) velocity at the reference height [m/s] (or "default" for JET velocity profile) [must be 1-hr mean for API model; otherwise is the mean over AnalysisTime seconds]
350                    ZJetMax     - Jet height [m] (used only for JET velocity profile, valid 70-490 m)
0.08                   PLExp       - Power law exponent [-] (or "default")
"default"              Z0          - Surface roughness length [m] (or "default")

--------Non-IEC Meteorological Boundary Conditions------------
"default"              Latitude    - Site latitude [degrees] (or "default")
0.05                   RICH_NO     - Gradient Richardson number [-]
"default"              UStar       - Friction or shear velocity [m/s] (or "default")
"default"              ZI          - Mixing layer depth [m] (or "default")
"default"              PC_UW       - Hub mean u'w' Reynolds stress [m^2/s^2] (or "default" or "none")
"default"              PC_UV       - Hub mean u'v' Reynolds stress [m^2/s^2] (or "default" or "none")
"default"              PC_VW       - Hub mean v'w' Reynolds stress [m^2/s^2] (or "default" or "none")

--------Spatial Coherence Parameters----------------------------
"IEC"                  SCMod1      - u-component coherence model ("GENERAL","IEC","API","NONE", or "default")
"IEC"                  SCMod2      - v-component coherence model ("GENERAL","IEC","NONE", or "default")
"IEC"                  SCMod3      - w-component coherence model ("GENERAL","IEC","NONE", or "default")
"12 0.00035273"        InCDec1     - u-component coherence parameters for general or IEC models [-, m^-1] (e.g. "10.0 0.3e-3" in quotes) (or "default")
"12 0.00035273"        InCDec2     - v-component coherence parameters for general or IEC models [-, m^-1] (e.g. "10.0 0.3e-3" in quotes) (or "default")
"12 0.00035273"        InCDec3     - w-component coherence parameters for general or IEC models [-, m^-1] (e.g. "10.0 0.3e-3" in quotes) (or "default")
"0.0"                  CohExp      - Coherence exponent for general model [-] (or "default")

--------Coherent Turbulence Scaling Parameters-------------------
".\EventData"          CTEventPath - Name of the path where event data files are located
"random"               CTEventFile - Type of event files ("LES", "DNS", or "RANDOM")
True                   Randomize   - Randomize the disturbance scale and locations? (true/false)
1                      DistScl     - Disturbance scale [-] (ratio of event dataset height to rotor disk). (Ignored when Randomize = true.)
0.5                    CTLy        - Fractional location of tower centerline from right [-] (looking downwind) to left side of the dataset. (Ignored when Randomize = true.)
0.5                    CTLz        - Fractional location of hub height from the bottom of the dataset. [-] (Ignored when Randomize = true.)
30                     CTStartTime - Minimum start time for coherent structures in RootName.cts [seconds]

====================================================
! NOTE: Do not add or remove any lines in this file!
====================================================

for high-resolution input file is

--------TurbSim v2.00.* Input File------------------------
for                    Certification - Test #1 (Kaimal Spectrum, formatted FF files).
---------Runtime Options-----------------------------------
False                  Echo        - Echo input data to <RootName>.ech (flag)
2318573                RandSeed1   - First random seed (-2147483648 to 2147483647)
RanLux                 RandSeed2   - Second random seed (-2147483648 to 2147483647) for intrinsic pRNG, or an alternative pRNG: "RanLux" or "RNSNLW"
False                  WrBHHTP     - Output hub-height turbulence parameters in binary form? (Generates RootName.bin)
False                  WrFHHTP     - Output hub-height turbulence parameters in formatted form? (Generates RootName.dat)
False                  WrADHH      - Output hub-height time-series data in AeroDyn form? (Generates RootName.hh)
True                   WrADFF      - Output full-field time-series data in TurbSim/AeroDyn form? (Generates RootName.bts)
False                  WrBLFF      - Output full-field time-series data in BLADED/AeroDyn form? (Generates RootName.wnd)
False                  WrADTWR     - Output tower time-series data? (Generates RootName.twr)
True                   WrFMTFF     - Output full-field time-series data in formatted (readable) form? (Generates RootName.u, RootName.v, RootName.w)
False                  WrACT       - Output coherent turbulence time steps in AeroDyn form? (Generates RootName.cts)
True                   Clockwise   - Clockwise rotation looking downwind? (used only for full-field binary files - not necessary for AeroDyn)
0                      ScaleIEC    - Scale IEC turbulence models to exact target standard deviation? [0=no additional scaling; 1=use hub scale uniformly; 2=use individual scales]

--------Turbine/Model Specifications-----------------------
51                     NumGrid_Z   - Vertical grid-point matrix dimension
49                     NumGrid_Y   - Horizontal grid-point matrix dimension
0.3                    TimeStep    - Time step [seconds]
4555.5                 AnalysisTime - Length of analysis time series [seconds] (program will add time if necessary: AnalysisTime = MAX(AnalysisTime, UsableTime+GridWidth/MeanHHWS) )
"ALL"                  UsableTime  - Usable length of output time series [seconds] (program will add GridWidth/MeanHHWS seconds unless UsableTime is "ALL")
157.0                  HubHt       - Hub height [m] (should be > 0.5*GridHeight)
300.0                  GridHeight  - Grid height [m]
288.0                  GridWidth   - Grid width [m] (should be >= 2*(RotorRadius+ShaftLength))
0                      VFlowAng    - Vertical mean flow (uptilt) angle [degrees]
0                      HFlowAng    - Horizontal mean flow (skew) angle [degrees]

--------Meteorological Boundary Conditions-------------------
"TIMESR"               TurbModel   - Turbulence model ("IECKAI","IECVKM","GP_LLJ","NWTCUP","SMOOTH","WF_UPW","WF_07D","WF_14D","TIDAL","API","USRINP","TIMESR", or "NONE")
"USRTimeSeries_T1.txt" UserFile    - Name of the file that contains inputs for user-defined spectra or time series inputs (used only for "IECKAI" and "TIMESR" models)
1                      IECstandard - Number of IEC 61400-x standard (x=1,2, or 3 with optional 61400-1 edition number (i.e. "1-Ed2") )
"6.100 "               IECturbc    - IEC turbulence characteristic ("A", "B", "C" or the turbulence intensity in percent) ("KHTEST" option with NWTCUP model, not used for other models)
"NTM"                  IEC_WindType - IEC turbulence type ("NTM"=normal, "xETM"=extreme turbulence, "xEWM1"=extreme 1-year wind, "xEWM50"=extreme 50-year wind, where x=wind turbine class 1, 2, or 3)
"default"              ETMc        - IEC Extreme Turbulence Model "c" parameter [m/s]
"PL"                   WindProfileType - Velocity profile type ("LOG";"PL"=power law;"JET";"H2L"=Log law for TIDAL model;"API";"PL";"TS";"IEC"=PL on rotor disk, LOG elsewhere; or "default")
"unused"               ProfileFile - Name of the file that contains input profiles for WindProfileType="USR" and/or TurbModel="USRVKM" [-]
150                    RefHt       - Height of the reference velocity (URef) [m]
9.0                    URef        - Mean (total) velocity at the reference height [m/s] (or "default" for JET velocity profile) [must be 1-hr mean for API model; otherwise is the mean over AnalysisTime seconds]
350                    ZJetMax     - Jet height [m] (used only for JET velocity profile, valid 70-490 m)
0.08                   PLExp       - Power law exponent [-] (or "default")
"default"              Z0          - Surface roughness length [m] (or "default")

--------Non-IEC Meteorological Boundary Conditions------------
"default"              Latitude    - Site latitude [degrees] (or "default")
0.05                   RICH_NO     - Gradient Richardson number [-]
"default"              UStar       - Friction or shear velocity [m/s] (or "default")
"default"              ZI          - Mixing layer depth [m] (or "default")
"default"              PC_UW       - Hub mean u'w' Reynolds stress [m^2/s^2] (or "default" or "none")
"default"              PC_UV       - Hub mean u'v' Reynolds stress [m^2/s^2] (or "default" or "none")
"default"              PC_VW       - Hub mean v'w' Reynolds stress [m^2/s^2] (or "default" or "none")

--------Spatial Coherence Parameters----------------------------
"IEC"                  SCMod1      - u-component coherence model ("GENERAL","IEC","API","NONE", or "default")
"IEC"                  SCMod2      - v-component coherence model ("GENERAL","IEC","NONE", or "default")
"IEC"                  SCMod3      - w-component coherence model ("GENERAL","IEC","NONE", or "default")
"12 0.00035273"        InCDec1     - u-component coherence parameters for general or IEC models [-, m^-1] (e.g. "10.0 0.3e-3" in quotes) (or "default")
"12 0.00035273"        InCDec2     - v-component coherence parameters for general or IEC models [-, m^-1] (e.g. "10.0 0.3e-3" in quotes) (or "default")
"12 0.00035273"        InCDec3     - w-component coherence parameters for general or IEC models [-, m^-1] (e.g. "10.0 0.3e-3" in quotes) (or "default")
"0.0"                  CohExp      - Coherence exponent for general model [-] (or "default")

--------Coherent Turbulence Scaling Parameters-------------------
".\EventData"          CTEventPath - Name of the path where event data files are located
"random"               CTEventFile - Type of event files ("LES", "DNS", or "RANDOM")
True                   Randomize   - Randomize the disturbance scale and locations? (true/false)
1                      DistScl     - Disturbance scale [-] (ratio of event dataset height to rotor disk). (Ignored when Randomize = true.)
0.5                    CTLy        - Fractional location of tower centerline from right [-] (looking downwind) to left side of the dataset. (Ignored when Randomize = true.)
0.5                    CTLz        - Fractional location of hub height from the bottom of the dataset. [-] (Ignored when Randomize = true.)
30                     CTStartTime - Minimum start time for coherent structures in RootName.cts [seconds]

====================================================
! NOTE: Do not add or remove any lines in this file!
====================================================

This verification was conducted under wind conditions where u, v, and w files could not be generated, so no u, v, or w files exist. However, I have saved the wind condition files and results I created using the OpenFAST-toolbox at the following URL.

Thank you for your kind consideration.

Best,

6

Dear @Yuki.Ogura,

Thanks for clarifying the origin of the old TurbSim files. @Regis.Thedin manages this repository and is out of the office for a bit, but I’ll have him update this upon his return.

Looking briefly at your files, the big issue I see is that TimeStep for the low-resolution domain is much larger than that for the high-resolution domain. And since the TIMESR option for the high-resolution domain uses wind time series derived from the low-resolution output, it does not have sufficient high-frequency data to construct the high-resolution output around. Reducing TimeStep of the low-resolution domain to match that of the high-resolution domain should solve this issue. I’ll talk to @Regis.Thedin about this as well.

Best regards,

7

Dear @Jason.Jonkman and @Regis.Thedin

Thank you for your reply.

Once again, I have two questions.

First question: When creating wind condition files using openfast-toolbox, the program automatically uses the DT_Low value for time steps in the inp file for the low-resolution. You mentioned changing this to use the DT_High value instead. Does this require rewriting the following section within the FASTFarmCaseCreation.py module located in the folder below?

.\openfast_toolbox\openfast_toolbox\fastfarm\FASTFarmCaseCreation.py

    def TS_low_setup(self, writeFiles=True, runOnce=False):
        # Loops on all conditions/seeds creating Low-res TurbSim box  (following openfast_toolbox/openfast_toolbox/fastfarm/examples/Ex1_TurbSimInputSetup.py)

        boxType='lowres'
        for cond in range(self.nConditions):
            for seed in range(self.nSeeds):
                seedPath = os.path.join(self.path, self.condDirList[cond], f'Seed_{seed}')
                
                # ---------------- TurbSim Low boxes setup ------------------ #
                # Set file to be created
                currentTSLowFile = os.path.join(seedPath, 'Low_stillToBeModified.inp')
                
                # Get properties needed for the creation of the low-res turbsim inp file
                D_       = self.allCases['D'   ].max().values
                HubHt_   = self.allCases['zhub'].max().values
                xlocs_   = self.allCases['Tx'  ].values.flatten() # All turbines are needed for proper
                ylocs_   = self.allCases['Ty'  ].values.flatten() # and consistent extent calculation
                Vhub_    = self.allCond.sel(cond=cond)['vhub'   ].values
                shear_   = self.allCond.sel(cond=cond)['shear'  ].values
                tivalue_ = self.allCond.sel(cond=cond)['TIvalue'].values
                # Coherence parameters
                a = 12;  b=0.12                            # IEC 61400-3 ed4, app C, eq C.16
                Lambda1 = 0.7*HubHt_ if HubHt_<60 else 42  # IEC 61400-3 ed4, sec 6.3.1, eq 5 
        
                # Create and write new Low.inp files creating the proper box with proper resolution
                # By passing low_ext, manual mode for the domain size is activated, and by passing ds_low,
                # manual mode for discretization (and further domain size) is also activated
                self.TSlowbox = TSCaseCreation(D_, HubHt_, Vhub_, tivalue_, shear_, x=xlocs_, y=ylocs_, zbot=self.zbot,
                                               cmax=self.cmax, fmax=self.fmax, Cmeander=self.Cmeander, boxType='lowres', extent=self.extent_low,
                                               ds_low=self.ds_low, dt_low=self.dt_low, ds_high=self.ds_high, dt_high=self.dt_high, mod_wake=self.mod_wake)

                if runOnce: return

                # Write the actual TurbSim input file. Here we set the total simulation time to one time-step
                # longer than the requested value. When executing the high-res boxes, sometimes the resulting
                # flowfield is shorter than the requested total simulation time. So if we ask for the low-res
                # with the exact length we want, the high-res boxes might be shorter than tmax. Note that the 
                # total FAST.Farm simulation time remains unmodified from what the user requested.
                self.TSlowbox.writeTSFile(self.turbsimLowfilepath, currentTSLowFile, tmax=self.tmax+self.dt_low, verbose=self.verbose)

                # Modify some values and save file (some have already been set in the call above)
                Lowinp = FASTInputFile(currentTSLowFile)
                Lowinp['RandSeed1'] = self.seedValues[seed]
                Lowinp['PLExp']     = shear_
                #Lowinp['latitude']  = latitude  # Not used when IECKAI model is selected.
                Lowinp['InCDec1']   = Lowinp['InCDec2'] = Lowinp['InCDec3'] = f'"{a} {b/(8.1*Lambda1):.8f}"'
                if writeFiles:
                    lowFileName = os.path.join(seedPath, 'Low.inp') 
                    Lowinp.write(lowFileName)

                # Let's remove the original file
                os.remove(os.path.join(seedPath, 'Low_stillToBeModified.inp'))

        self.TSlowBoxFilesCreatedBool = True

Second question: Regarding the parameter fmax specified within the executable file Ex2a_FASTFarm_TurbSim_driven.py, the description states it is the Maximum excitation frequency (Hz). Please advise what value should be used when creating wind conditions for an IEA-15-240-RWT wind turbine. If documentation exists, please provide that as well.

openfast_toolbox/openfast_toolbox/fastfarm/examples
/Ex2a_FASTFarm_TurbSim_driven.py

I apologize for bothering you during your busy schedule, but I would be grateful if you could share your opinions.

Best regards,

8

Dear @Yuki.Ogura,

I wouldn’t say that the routine needs to be rewritten, but like you said, you should change the script slightly to swap DT_Low with DT_High when setting the TimeStep in TurbSim for the low-resolution domain.

Regarding fmax for the IEA 15-MW RWT, typically we set fmax equal to either 9-12P or just above the second tower-bending mode, which for the IEA 15-MW RWT are:
9P: 1.1325 Hz (based on 7.55 rpm rated speed)
12P: 1.51 Hz
2nd tower: 1.61 Hz

So, fmax need not be larger than 2 Hz, and even that my be high.

Best regards,

9

The issue you pointed out has been fixed on commits from May (FF: changes in turbsim-based boxes generation. See extended message · OpenFAST/openfast_toolbox@54fbd3a · GitHub and FF: clean-up and small fixes · OpenFAST/openfast_toolbox@67e88b2 · GitHub). Can you make sure you have the latest version of the toolbox and give it another go?

The time-step should have been written correctly, as it is coming from the variable dt here, which gets set here for the low-res, and here for the high-res.

10

Dear, @Regis.Thedin

Thank you for making the program modifications.

Verification revealed that DT_Low, not DT_High, was used in the low-resolution domain of the inp file. This resulted in the generation of a .bts file for the high-resolution region, similar to this one ( Creating u, v, and w files using TurbSim - #3 by Yuki.Ogura ), where high-frequency vibrations were lost.

To resolve this issue, rewrite the following section within the FASTFarmCaseCreation.py module:

                self.TSlowbox = TSCaseCreation(D_, HubHt_, Vhub_, tivalue_, shear_, x=xlocs_, y=ylocs_, zbot=self.zbot,
                                               cmax=self.cmax, fmax=self.fmax, Cmeander=self.Cmeander, boxType='lowres', extent=self.extent_low,
                                               ds_low=self.ds_low, dt_low=self.dt_high, ds_high=self.ds_high, dt_high=self.dt_high, mod_wake=self.mod_wake)

this approach resolved the issue of high-frequency components being lost in the .bts files for the high-resolution domain.

Also, since the inp files for this page (https://github.com/OpenFAST/openfast_toolbox/blob/main/openfast_toolbox/fastfarm/examples/SampleFiles/template_HighT1_InflowXX_SeedY.inp) and that page (openfast_toolbox/openfast_toolbox/fastfarm/examples/SampleFiles/template_Low_InflowXX_SeedY.inp at main · OpenFAST/openfast_toolbox · GitHub) are still outdated, I would appreciate it if you could update them to the latest versions.

Best regards,