Dynamic Responses and Wake Characteristics of a Floating Offshore Wind Turbine in Yawed Conditions

Abstract

A coupled large eddy simulation and aero-hydro-moor-servo dynamics code is used to perform numerical simulations of a floating offshore wind turbine (FOWT) under yawed conditions. The atmospheric boundary layer wind field is simulated by large eddy simulation (LES) with sufficient simulation duration as the inflow wind condition. Two cases with 15° and 30° yaw angles of wind turbine are performed, and the results of aerodynamics, hydrodynamics and wake characteristics are compared and analyzed with that of non-yaw scenario. It is concluded that the rotor power of FOWT decreases with increase of yaw angle, whereas the rotor thrust of 15° yaw angle is slightly larger than that of non-yaw situation. There is no distinct difference of platform surge motion and pitch motion between the 15° yaw angle and non-yaw scenario, whereas the two motions of 30° yaw angle are significantly less than that of non-yaw scenario. The platform sway motion increases with the increase of yaw angle due to the crosswise component of rotor thrust of wind turbine. What’s more, faster wake recovery and more significant wake deflection with increase of yaw angle is observed, which is beneficial for the inflow wind condition and power generation of downstream wind turbine.