Study on aerodynamic and coupled motion response characteristics of floating vertical axis wind turbine

To improve the efficiency of a floating VAWT (FVAWT), the aerodynamic and coupled motion response characteristics of 5MW Phi-type FVAWT are studied in fully coupled system. Based on the computational fluid dynamics (CFD) method, the dynamic fluid body interaction (DFBI), overlapping grid and dynamic mesh technique are adopted for numerical simulations. Under wind-wave coupling conditions, the power coefficient (Cp) and motion response of FVAWTs with different tip speed ratios (TSR) and height-todiameter ratios (eta) are analysed. The mechanism of platform heave motion on torque Q generation of VAWT is explored. The results show that the FVAWT with height-to-diameter ratio of 1.2 and tip speed ratio of 5 has optimal aerodynamic and motion performance. Under the optimal tip speed ratio, the Cp of the offshore FVAWT is 5.21% higher than that of the land VAWT. As the floating platform rises, the torque of wind turbine decreased correspondingly, and vice versa.