Toward Identifying Aeroelastic Mechanisms in Near-Wake Instabilities of Floating Offshore Wind Turbines

Abstract

A free-vortex-wake aeroelastic framework evaluates the impact of blade elasticity on the near-wake formation and its linear stability for onshore and offshore configurations of the National Renewable Energy Laboratory (NREL) 5 MW reference wind turbine. Numerical results show that motion of the flexible rotor further destabilizes its tip-vortices through earlier onset of mutual inductance relative to the rigid rotor results for onshore and offshore turbines. The near-wake growth rate is demonstrated to depend on the azimuthal position of the rotor for all cases considered, which appears to not have been reported previously for wake stability analyses in the rotorcraft literature.