Dear All
I have a very simple question about FAST-SC. I know maybe this is not the best place to ask the question about FAST-SC however I am in hurry to conduct the simulation and the question is very simple so maybe a lot of friends could answer it quickly.
The question is about the external force inputted from Simulink for FAST-SC. I am wondering if the external force inputted from Simulink is exerted both on the TMD mass and the nacelle or only exerted on TMD mass? I want to use the active controller to generated some force to control the vibration of the tower top. I think I can only input the control force through the external force channel in FAST-SC if the force will be exerted both on the nacelle and the TMD mass, right?
Best
XING WEI
Dear Xing.Wei,
I can’t comment on FAST-SC, but I know that the external force in the TMD submodule of ServoDyn within FAST v8 / OpenFAST applies equally and oppositely to the TMD and nacelle (for nacelle-based TMDs) and tower (for tower-based TMDs).
For questions directly about FAST-SC, I would suggest reaching out to Professor Matthew Lackner of the University of Massachusetts-Amherst.
Best regards,
Dear Jason
Could you please kindly guide me to where I can input the external force in FAST 8. I checked the ServoDyn.dat and ServoDyn_TMD.dat but I could not find where to input the external force. I hope to input it from Simulink.
Best
XING WEI
Dear Xing,
There is a MiscVar in the TMD submodule called F_ext that represents the external force. I believe this is a placeholder (currently F_ext is always set to zero) for calculating the external force through a subroutine or Simulink, although direct interfaces to define it have not been included in the dev or master branches of OpenFAST. It could be that Prof. Matthew Lackner or his students have further developed these interfaces and not yet shared them with the community. Again, I would reach out to Prof. Lackner. Or you could modify the source code yourself.
Best regards,