Dear Jason,
I want to generate inflow for OpenFAST using OpenFOAM, but there are several aspects I don’t fully understand. First, how can I cut a section in OpenFOAM to extract the external inflow for OpenFAST? Second, after successfully extracting the external inflow, if I set CompInflow=2 in OpenFAST, do I need to replace the inflow file in the *.fst input file section?
Best regards,
Dereje
Dear @Dereje.Haile,
Can you clarify your use case? Do you want to run OpenFAST as a preprocessing step to generate inflow (e.g., to characterize inflow for a given atmospheric stability or flow over terrain) for OpenFAST? Or do you want to run OpenFAST coupled to OpenFOAM through an actuator-line method, e.g., using SOWFA?
The CompInflow = 2 option of OpenFAST is for the latter, but for the former, CompInflow = 1 should be used and you should format your OpenFOAM output in a form InflowWind can understand, e.g., TurbSim format.
Best regards,
Dear Jason,
Thank you for your prompt reply.
Yes, I want to run OpenFOAM as a preprocessing step to generate inflow for a given atmospheric stability for OpenFAST. However, I didn’t understand well the way to extract that from desired section of OpenFOAM.
Best regards,
Dereje
Dear @Dereje.Haile,
You’ll want to export time series of wind velocities at points across a vertical (Y,Z) sampling plan from OpenFOAM. You should then write this data to a format InflowWind can read, such as the TurbSim binary (.bts) format or HAWC format.
I’ve not used these myself, but I believe there are python scripts available in the WindTools repository that already support this: windtools/windtools/inflow at main · NREL/windtools · GitHub.
Best regards,
Thank you very much.
There are three Python codes included: general, OpenFAST, and synthetic. However, I am not sure which of them can generate the .bts format. If anyone knows, please help.
Best regards
Dereje
Dear @Dereje.Haile,
Looking briefly through these scripts, I see routine write_binary_from_netcdf() in openfast.py that will write a HAWC-formatted binary file based on netcdf output from OpenFOAM, but I don’t see an equivalent writer for TurbSim’s bts format. I do, however, see a reader for TurbSim bts format via routine _readBTS() in synthetic.py. So, with a bit of recoding, I’m sure a bts writer could also be coded. That said, this may not be necessary because InflowWind can read HAWC-formatted binary inflow files.
Best regards,