Dynamic response analysis of a floating dual-rotor wind turbine based on model testing in wave basin

Motivated by growing demand for innovative design of wind turbines, this study presents the scaled model design and wave basin testing of a novel 5 MW-5 MW floating dual-rotor wind turbine (FDRWT). The FDRWT involves two aerodynamic thrust sources and direction-dependent rotor gyroscopic effects, making rotor configuration an important factor in its coupled dynamic response. A 1:60-scale model was developed based on aerodynamic thrust similarity, structural stiffness similarity, and Froude scaling. Model blades were optimized using a gradient-descent method, while the tower, platform, and mooring system were designed to preserve the structural and hydrodynamic characteristics. Model tests were conducted under wind and wave conditions. Co-rotating (CO) and counter-rotating (CR) configurations were further examined to assess the influence of rotor configuration on platform motion and mooring response. Results show that rotor rotational configuration has a pronounced influence on the coupled response of the FDRWT. At a below-rated wind speed, the pitch under the CR configuration is significantly reduced compared with the CO configuration. The CR configuration also suppresses the 3P-dominated response, although enhanced 1P excitation and increased mooring-load fluctuations are observed under operating conditions. These findings highlight the trade-offs associated with rotational configuration and provide guidance for integrated design of FDRWTs.