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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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Error in Inflow wind file #622

Closed SudharsanKalidoss closed 3 years ago

SudharsanKalidoss commented 3 years ago

Hi everyone,

I'm running the NREL 5 MW wind turbine with tlp platform. When I tried running the case, I get an error message stating that the ref height is negative in inflow wind file. I tried running monopile case with same wind file and it worked. But it shows error for TLP case. I have attached the error.

Sudharsan Inflow_neg_ht

jjonkman commented 3 years ago

Dear @SudharsanKalidoss,

Did you change this r-test TLP case in some way?

The error is triggered because an aerodynamic analysis node on the tower has heaved downward a tiny amount (-1.08935E-04 m), and there is no wind data in the TurbSim file below the mean sea level (0.0 m). Due to its design, I would not expect the TLP to heave downward by much. So, the simple solution is likely to raise the lowest tower aerodynamics node in AeroDyn. Currently, the lowest node is at TwrElev = 0.0 m, so, any downward motion will trigger an error. Raising TwrElev from 0.0 to something a bit higher (say from 0.0 to 1.0 m) should solve the problem. Disabling tower aerodynamic loads in AeroDyn (TwrAero = False) should also solve the problem.

Best regards,

SudharsanKalidoss commented 3 years ago

Dear @jjonkman,

Thank you for your help. I moved the tower lowest node higher and it worked.