An experimental study on the aerodynamic-induced effects of a semi-submersible floating wind turbine

Compared with land-based wind turbines, investigating the aerodynamic-induced effects of floating wind turbines (FWTs) is more challenging due to the aero-hydro-elastic-moor-control coupled characteristics. This study aims to examine the aerodynamic-induced effects of a newly designed 5 MW semi-submersible floating wind turbine through wave basin model tests, including the aerodynamic damping effect, the gyroscopic moment effect, and the nacelle-wind misalignment effect. The results indicate that an increase in wind speed leads to a decrease in platform surge-induced aerodynamic damping, while it results in an increase in platform pitchinduced aerodynamic damping. The presence of wind damps the wave-frequency tower vibration response and alters the tower's natural frequency. The spinning rotor and platform pitch motion are identified as two crucial factors contributing to the gyroscopic moment. Under rated conditions, the influence of the gyroscopic moment on the platform yaw motion is more significant than that of wave actions. The nacelle-wind misalignment leads to larger mean surge and pitch motions, as well as larger tower-base bending moments due to the increased aerodynamic loads on the rotor. Furthermore, the misalignment effect also impacts the discrepancy in the fairlead tensions of the mooring lines arranged in the upwind direction.