Dear all,
In order to obtain frequenty-dependent aerodynamic damping of floating wind turbine,I want to obtain the aerodynamic thrust(RtAeroFxh in outlist) through simulation satisfying the following relation:
OpenFAST only seems to define nacelle forces, not nacelle speed, so I decouped hydrodyn and moordyn by ExtPtfm module, given the forced motion.
Here is my ExtPtfm input file:
In order to get the ideal motion and ideal RtAeroFxh, my Elastodyn and Aerodyn have the following Settings:
The Nacelle motion met my expectations.
At non-rated wind speed, the trend of
RtAerofxh is ideal, but the peak value fluctuates slightly when the period is larger.
Here are the questions:
At the rated wind speed, the output RtAeroFxh has unexpected fluctuations, and the fluctuations become more significant as the period of forced oscillation increases:
There seems to be a frequency disturbance, and I want to know what exactly is causing the aerodynamic force to fluctuate? Why does it get more and more significant as the motion period become longer?
As a final supplement, the model I used is 5MW DeepCwind semi-submersible wind turbine.The controller I have used is
5MW-OC3Hywind.dll.
Please forgive me for saying so much and for making some mistakes in English grammar. If you can read it and give me some suggestions, I would be grateful!
Best regards,
He.Li