Aerodynamic damping of the nacelle, tower and the blades

Dear @Jason.Jonkman,

I have known recently that aerodynamic damping due to wind is beneficial to damp the oscillations of the tower top in fore aft direction. However, i didn’t find any equivalent damping ratio to the aerodynamic damping in Aerodyn blade. Am i wrong ?
How did you take into account this in OpenFast ? And do you know what is the equivalent damping ratio (numerical values) ?

Thank you a lot,



Dear @Riad.Elhamoud,

Aerodynamic damping is calculated by OpenFAST as a result of the coupling between the structural module (ElastoDyn or BeamDyn) and the aerodynamic module (AeroDyn). That is, the aerodynamic loads calculated by AeroDyn and sent to structural module depend on the structural motions (position/orientation and velocity of the various analysis nodes) sent from the structural module to AeroDyn.

The linearization functionality of OpenFAST can be used to quantify the damping of various full-system modes of the wind turbine during operation, including the effects of aerodynamic damping.

Best regards,

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