Question about RootMzb1 Simulation Result

[sstonee2024]

Hi,

I noticed that the simulation result "RootMzb1" (blade 1 pitching moment at the blade root for 5MW wind turbine) shows a sinusoidal trend even though I set the wind speed to a steady 12 m/s. I am wondering why this happens. Is it due to the aerodynamic loading? What is the root cause of this type of curve?

Thank you very much for your help.

[jjonkman]

Dear @sstonee2024,

You haven't clarified other simulation settings, but I assume the rotor is operating, the NREL 5-MW turbine geometry is unchanged, and all structural degrees of freedom are enabled. In that case, I would assume this oscillation comes from periodicity in the system coming from gravity, shaft tilt, turbine deflection, etc.

Best regards,

[sstonee2024]

Thank you very much for your reply, Mr. Jonkman. Have a great weekend.