Abstract
The increasing demand to harness offshore wind resources has pushed offshore wind turbines into deeper waters, making floating platforms more economically feasible than bottom-fixed ones. When the incident wind and wave forces act on the floating wind turbine, the floating platform will experience oscillations around its equilibrium position in six degrees of freedom (DOFs). Significant floater motions can affect the aerodynamic power output, increase the failure risk, and even shorten the operational lifetime, especially under a harsh offshore environment. To improve the dynamic behavior of the floating platform, this research designed a heave plate for an OC4-Deepcwind wind turbine. The dynamic performance of the wind turbine was specifically investigated based on a series of wave-basin model tests, including free decay tests, regular wave tests, and irregular wave with steady wind tests. The results show that the heave plate increases damping in heave and pitch motions. The weakening effect on the heave and pitch motion is obvious in the wave period of 15–20 s and 20–27 s, respectively. However, the arrangement of the heave plate may exacerbate the fluctuation of the force and moment at the bottom of the tower.