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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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The Average of the RotTorq at Rated Wind Speed #1979

Closed 126qoq closed 5 months ago

126qoq commented 5 months ago

Dear Dr. Jonkman,

I am now working om the Test 25 of the NREL 5 MW-OC4-DeepCwind SemiSubmersible wind turbine. While investigating the wind turbine wind rotor torque, I found that the average of the rotor torque does not reach the value given in the Definition of a 5-MW Reference Wind Turbine for Offshore System Development at 11.4 m/s steady state wind. Considering the aeroelastic response of the blades, I disabled the blade Flap and Edge degrees and recalculated the mean value of the rotor speed at different wind speeds to get the results as shown in Fig. 1, which are compared with those shown in the file but are still less than ideal. I'm wondering if the lower RotTorq at rated wind speed is normal or if there is something wrong with my codes.

Best regards, Yao Ge

001 Figure 1

jjonkman commented 5 months ago

Dear @126qoq,

The report you reference for the NREL 5-MW baseline wind turbine (NREL/TP-500-38060) documents the land-based wind turbine. I suspect the floater motions (especially platform pitch) of the NREL 5-MW baseline turbine atop the OC4-DeepCwind semisubmersible will change the steady-state value of rotor torque a bit from what is documented in NREL/TP-500-38060. I would guess your results would better match NREL/TP-500-38060 if you disabled the platform degrees of freedom in ElastoDyn.

Best regards,

126qoq commented 5 months ago

Dear Dr. Jonkman,

Thank you for your answer. I get the answer I want.

Best regards,