Preliminary stability design method and hybrid experimental validation of a floating platform for 10 MW wind turbine

Platform motions induced by wind and waves import strong nonlinear coupling effects in the aerodynamic characteristics of floating offshore wind turbines (FOWTs), which exacerbate the power instability of the wind turbine and should be considered during the preliminary platform design stage. For this reason, a platform motion-based method was proposed to estimate the power stability and successfully applied to the preliminary platform stability design in this paper. Firstly, a high-fidelity computational fluid dynamics (CFD) model of a 10 MW wind turbine was established using the oversetting grid and superposition motion technology. Then the influence laws of platform surge and pitch motions on the power characteristics of the wind turbine were summarized. Subsequently, a semi-submersible floating platform structure for supporting the 10 MW wind turbine was designed preliminarily. The power stability of the wind turbine and tilting stability of the platform were analyzed based on the hydrodynamic analysis results. Finally, a hybrid scaled model of the 10 MW FOWT was built, incorporating a six-degrees of freedom load actuation system based on multi-fans. The scaled model test was carried out in a wave basin, demonstrating that both the power stability and the tilting stability of the platform meet the proposed stability requirements.