Frequency-dependent aerodynamic damping and its effects on dynamic responses of floating offshore wind turbines

Abstract

This study investigates how the frequency-dependent characteristics of aerodynamic damping influence the dynamic responses of a floating offshore wind turbine (FOWT). To accomplish this, we established an aero-hydro-servo-structure coupled model for the OC4 DeepCWind wind turbine, and validated the aerodynamic and hydrodynamic models based on thrust force, mooring stiffness, hydrodynamic damping, and natural periods of platform motions. We identified and analyzed both the constant and frequency-dependent aerodynamic damping of the referenced wind turbine, and investigated their effects on platform motions, nacelle acceleration, and tower bending moment. Our findings highlight the close relationship between aerodynamic damping and the natural periods of platform motion in terms of suppression or amplification effects. We strongly recommend considering the contributions of frequency-dependent aerodynamic damping in a decoupled model.