Research on the dynamical responses of H-type floating VAWT considering the rigid-flexible coupling effect

Abstract Offshore floating wind turbines are classified into floating horizontal axis wind turbines (HAWTs) and floating vertical axis wind turbines (VAWTs) according to the orientation of rotating shaft. Compared with the traditional floating HAWTs, main advantages of floating VAWTs are the independence of wind direction and the lower position of power generating system, which reduce the installation and maintenance costs. Dynamical characteristics of floating VAWTs were widely studied in the preceding researches by tackling the wind turbine as a rigid body. However, the increasing size of wind turbine is beneficial to achieve higher cost performance. The elastic deformations of slender structures including blades and tower should be considered when the dynamical characteristics of the floating wind turbine are studied. In this paper, rigid-flexible coupling equations were established to investigate the dynamic behavior of H-type floating VAWT based on multi-body kinematics and dynamics. Natural motion performances of the wind turbine structures were presented and the phenomenon of “dynamic stiffening” was analyzed. Motions of the floater and vibrations of the tower and blades were computed under complex environmental loads. Time domain and frequency domain simulations were carried out to study the dynamic response of floater, tower and blades, respectively. Besides, the effect of aerodynamic loads and wave loads on the floating VAWT was researched. Load transfer performance through rigid and flexible structures was investigated.