Study on wake characteristics of fixed wind turbines and floating wind turbines arranged in tandem

Because of the growing demand for floating wind turbines with a limited number of floating prototypes, offshore wind farms require a hybrid arrangement of fixed and floating wind turbines. Studying the wake characteristics of bottom-fixed and floating wind turbines, as well as the layout optimization of hybrid wind farms, is important for utilizing more wind energy through hybrid wind farms. In this study, numerical simulations based on the fully coupled aero-hydro-servo-elastic method and the dynamic wake meandering model were performed to investigate wind turbines arranged in tandem. First, the wake and dynamic aerodynamic characteristics were used to verify the accuracy of FAST.Farm. Subsequently, numerical simulations were conducted on two tandem offshore NREL 5-MW wind turbines under different arrangements to study the differences in wake characteristics, dynamic behavior, and optimized layout between floating and bottom-fixed turbines. The results indicate that compared with bottom-fixed turbines, floating turbines exhibit faster wake recovery, resulting in less impact on downstream wind turbines. Although they possess lower individual power, they ensure higher power for the downstream turbines. In a hybrid arrangement, it is advisable to position the floating turbines upstream to optimize the overall power output.