Research on hydrodynamics of foundation structure of offshore wind turbine under typhoon-wave-current coupling

Abstract

Offshore wind turbine is facing with extremely complicated climatic environment. The accurate prediction of wave movement caused by strong typhoons and its action on foundation of wind turbine are crucial. To disclose hydrodynamic characteristics of foundation structure of wind turbine under typhoon-wave-current coupling effect on the sea, a 10 MW super-large offshore wind turbine in Wailuo Wind Farm, Guangdong was chosen as a research object and a real-time meso-scale WRF-SWAN-FVCOM (W-S-F) coupling simulation platform was constructed by using Model Coupling Toolkit The spatial-temporal evolution of typhoon-wave-current in the offshore wind farm was simulated when a super typhoon “Rammasun” passed through. Next, the hydrodynamic load distribution characteristics of single pile foundation of wind turbine were analyzed by combining the meso-micro scale nested method. Extreme load model of foundation piles under different wave phases was proposed. Results demonstrated that the constructed W-S-F platform increased the simulation precision of typhoon path by 42.51% than single WRF model. The horizontal wave force of the foundation pile reached the negative and positive peaks at phases T0 and T4 under typhoon-wave-current coupling, and it presented symmetric distribution circumferentially around the 180° angle of wave attack. The phase T4 was the most adverse phase for the strength design of single pile foundation of offshore wind turbine. At the bottom of foundation, the maximum shear reached the 7.68 × 106 magnitude and the maximum bending moment reached the 5.2 × 108 magnitude.