IEA-22-280-RWT-monopile simulation based openfast

Wind & Water Computer-Aided Engineering Software Tools
1

Dear NREL OpenFAST Team,

I am currently practicing OpenFAST simulations using the IEA-22-280-RWT model provided on your GitHub repository.
While verifying the steady-state results of the turbine under a wind speed of 5 m/s, I noticed that most of the output values (e.g., generator speed, torque, power, pitch angle) matched well with the values reported in the “IEA Wind 22-MW Reference Wind Turbine” documentation.

However, the Rotor Thrust value shows a significant deviation — approximately **50% ** higher than the reported result.

Is it possible that only the Rotor Thrust differs while other values match in such a scenario?
If so, could you please suggest which modules, input files, or settings I should inspect to resolve this discrepancy?

The current subdyn.dat and hydrodyn.dat files in the Monopile folder on the GitHub repository differ from the ones compatible with the latest OpenFAST version, so I updated both files to match the v4 input format before running the simulation. I would like to ask whether this modification could be the reason for the difference in Rotor Thrust.

I attached screenshot for reference:

  • The image shows the Rotor Thrust value obtained from my OpenFAST simulation using the provided GitHub input files without modifications.

image
image1627×875 179 KB

Thank you in advance for your support.

Best regards,
[simu jung]

2

Dear @SiMu.Jung,

I would not think changing the monopile properties in SubDyn or HydroDyn or switching versions of OpenFAST would impact the rotor thrust.

You mention that only the rotor thrust is off, while other outputs look correct. Are you comparing the correct rotor thrust output of OpenFAST? I see you using ElastoDyn output RotThrust, but this output not only includes the aerodynamic thrust, but also the weight and inertia of the rotor projected along the shaft (which is the reaction force that a strain gage would measure along the shaft). If you want to compare only the pure aerodynamic rotor thrust, I would use AeroDyn output RtAeroFxh instead.

Best regards,