Control for scaled-down 5MW NREL

Dear Dr. Jason

Thank you very much for your time and quick reply.

I am using FAST V8. After learning the code, I plan to modify FAST_Prog.f90 of FAST V8 according to the Labview interface of FAST V7. In FAST_Prog.f90, I will replace FrcT0Trb and MomX0Trb by the measured tower-base loads and output the OtherState%AllOuts( PtfmTDxi、 PtfmTDyi、 PtfmTDzi、PtfmRDxi、 PtfmRDyi、 PtfmRDzi) as platform displacement into the Labview program. Do you think this modification is correct and feasible?

Best regards,
Gary.Wu

Dear Gary,

Just a few comments:

  • If you are going to upgrade a version newer than FAST v7 to reintroduce the Labview interface, I would start with OpenFAST (github.com/OpenFAST/openfast), where all active FAST development is taking place. If you are already familiar with FAST v8, then it should not be hard to upgrade to OpenFAST, which is based on, and contains improvements relative to, FAST v8.
  • FrcT0Trb and MomX0Trb are local variables within the ElastoDyn module, and so, are not available to the the FAST glue code, including FAST_Prog.f90. These variables also contain the entirety of applied and inertial forces of the rotor + drivetrain + nacelle + tower, which it doesn’t sound like what you want.
  • It sounds like what you want is to replace the aerodynamic applied loads computed by AeroDyn with those derived from the wind tunnel. If these loads will be expressed as a single lumped load (3 forces, 3 moments), you should set the input to the ElastoDyn module (HubPtLoad%Force, HubPtLoad%Moment on the HubPtLoad input mesh).
  • I’m not sure what you mean by “OtherState%AllOuts”; I don’t see that such a variable exists in the source code. What do you plan to physically model in the wind tunnel, e.g., is tower flexibility considered? If so, I would expect that you’d want to output the motions at the tower-top rather than the motions at the tower-base/platform anyway.

Best regards,

Dear Dr. Jason

I will also try to start with OpenFAST to develop the wind tunnel test method. Now I have understood the meaning of FrcT0Trb and MomX0Trb clearly based on your guidance. In the wind tunnel test, tower flexibility will not be considered. In this case, I think there exists a kind of fixed relationship between the motions at the tower-top and tower-base. I will ask you for help again when encountering new problems.

Thank you very much for the great guidance.

Best Regards
Gary.Wu