Hello!
I have a question regarding the loads at the top of the wind tower. I tried the search function of the forum, but I came to different answers in different time frames for different versions of openFAST so I was hoping to clarify this vital point.
I’m modelling the OC4 reference jacket paired with a 5MW NREL wind turbine. I had to simplify my model but the wind loads I extract directly from openFAST and apply at the top of the tower (I use a lumped mass approximation to the Rotor-Nacelle-Assembly with weight and Inertias). My question is, what would be the most correct output channel for loads and moments to be applied at the very top of the tower in x, y and z that would not be affected by some Inertia openFAST may consider?
Dear @Filipe.Rocha,
A similar question was recently asked and answered in the OpenFAST GitHub repository: Calculation of wind turbine aerodynamic forces · Issue #2809 · OpenFAST/openfast · GitHub. Does this discussion answer your question?
Best regards,
Dear Jason, hi! Sorry for my delayed reply but I think I understood which loads I should use. Interestingly there’s a spike in the force value in the direction the wind is dominant (in my case, x direction) at the beginning of the simulation. Do you have some recommendation as to discard these initial values because of some mechanics the rotor may have? I’m using the values of RtAeroFxi.
Dear @Filipe.Rocha,
Perhaps you want to clarify your simulation set up and the type of spike you are seeing. Regardless, we generally recommend ignoring the output of the simulation until the simulation start-up transient has passed before post-processing for response and load metrics.
Best regards,