An Experimental Study on Effects of Aerodynamic Damping of a 5MW Semi-Submersible Floating Vertical Axis Wind Turbine

Floating vertical-axis wind turbines (FVAWTs) offer certain advantages over floating horizontal-axis wind turbines (HAWTs), particularly in terms of the potential to lower the cost of energy. In this study, a 5MW FVAWT concept with three straight blades and a semi-submersible hull deployed in a water depth of 42 m was presented. In addition, the experimental setup is introduced, and calibration tests are also performed to validate the physical model system. The aerodynamic damping in surge and pitch motions was measured by comparing the decay experimental results with and without wind loads. Following this, wind/wave basin model tests with a scale ratio of 1/50 were conducted to explore the effect of aerodynamic damping on the motion characteristics of this turbine concept. Results indicate that aerodynamic damping can suppress the fluctuations of the platform’s surge and pitch motion at their respective resonance frequencies and tends to increase with wind speed at below-rated wind speed. Additionally, surge-induced and pitch-induced aerodynamic damping hardly affect the wave frequency response. Meanwhile, the surge natural frequency is substantially altered due to the wind loads. This study contributes to providing valuable insights into the aerodynamic damping of floating VAWTs.