Fully coupled dynamic analysis of novel floating dual-rotor wind turbines

This paper employs a fully coupled aero-hydro-servo-elastic approach to develop numerical models for the 10 MW floating single-rotor wind turbine (SRWT) and the 5 MW-5 MW floating dual-rotor wind turbine (DRWT). A series of numerical simulations was conducted to investigate the aerodynamic characteristics, wake characteristics, dynamic response, and tower base force characteristics of two types of wind turbines. The results under three conditions—wind only, wave only, and combined wind and wave were analyzed and compared. The results indicate that the rated wind speeds of the floating SRWT and DRWT are 11.4 and 14 m/s, respectively. Under wind-only conditions, the aerodynamic force of DRWT is greater than that of SRWT when the wind speed reaches the rated speed of DRWT. However, when the wind speed is below the rated speed of DRWT, the results are the opposite. Regarding aerodynamic wake recovery, the DRWT demonstrates greater advantages due to the mutual interaction and mixing of the wakes. In terms of platform motion and tower base forces, the DRWT not only exhibits greater stability in sway, heave, roll, and yaw degrees of freedom but also shows lower average values for both the force and bending moment at the tower base. Under combined wind and wave conditions, the DRWT exhibits more complex high-frequency response characteristics compared to the SRWT. This paper offers a comprehensive analysis of the floating DRWT in comparison with the floating SRWT and provides insight for future design optimizations of DRWTs.