TwrBsMyt & RotThrust

Wind & Water Structural Analysis
2

Dear Lingling Yin,

I have no experience with this particular FAST model, but I’ll try to answer your questions.

  1. I think the answer to this question is sufficiently discussed in my August 18, 2009 post in the forum topic found here: RotThrust, LSSTipMya, TwrBsMyt.
  2. Unless you pitched the blades to create zero rotor torque, the wind loads on the rotor will generator a torque that will lead to a tower-base moment about the xt axis.
  3. I’m not sure I understand your question. Regardless, FAST output TwrBsMyt (and other tower loads output from FAST) are useful for analyzing the bending stress level in tower design.
  4. This is a difficult question to answer in general, but the case you describe sounds severe enough to warrant the enabling of structural DOFs.

Best regards,