Power performance of a model floating wind turbine subjected to cyclic pitch motion: A wind tunnel study

Offshore floating wind turbines (OFWTs) are becoming increasingly popular due to their ability to exploit deep-sea wind resources. However, since wind turbines are installed on floaters instead of solid foundations, the dynamic response of an OFWT due to the wind-wave-structure coupled effects can bring structure safety concerns and affect the power performance. The dynamic response of an OFWT can be described by motions in six different degrees of freedom (DOFs) or directions, which are surge, sway, heave, roll, pitch and yaw. Among the six DOFs, the two most pronounced motions are surge motion and pitch motion, which are the fore-and-aft translation and rotation, respectively. During the pitch motion, as the pitch angle changes, the motion-induced out-of-plane rotor velocity varies continuously, and so does the inflow condition because the closer to the surface, the lower the streamwise inflow velocity and the higher the turbulence intensity. In the current study, we perform wind tunnel experiments with a miniature wind turbine model to investigate the effects of sinusoidal pitch motion on power performance.