Dynamical Response Numerical Analysis Of The Offshore Wind Turbine Under Combined Action Of Wind And Wave

The dynamical response numerical analysis of the offshore wind turbine under combined aerodynamic loads and wave loads are always important hot topics and research subjects in the research field of offshore wind turbine technology. With wind turbine becoming larger and more flexible and the confluence of wind and waves, the performance and stability of the offshore wind turbine cause domestic and foreign researchers’ attention. In this study, The wave loads acting on the cylindrical support foundation were analyzed. The nonlinear elastic deformation of flexible components was described with a limited number of degrees of freedom based on the modeling method of computational dynamics of multi-body systems. the fluid-solid coupling analysis of system was realized based on the modern computational dynamics of offshore wind turbine system combining with aerodynamic load model, wave load model and efficient numerical method. The research contents and results have important significance in theory and practical application.The U.S. National Renewable Energy Laboratory 5MW horizontal axis wind turbine system was research object, the complex working conditions of offshore wind turbine were analyzed, offshore wind turbine system was divided into two subsystems:flexible body subsystem and rigid body subsystem, The system was divided into 48 of rigid body and 78 degrees of freedom. The wind turbine dynamic equations were obtained by the modeling method for hybrid multibody system based on the theory of computational dynamics of multibody system. Linear wave theory was employed to simulate irregular wave and to calculate the water particles’ velocities and accelerations at various depths. The calculation model of wave force acting on the support foundation of tower was established by using Morison wave force equations. The wave loads acting on the cylindrical support foundation were analyzed. Application blade element theory, blade was divided into multiple blade element, those blade are independent of each other, a three-dimensional model was reduced to a two-dimensional model, which can be used airfoil aerodynamic characteristics to calculate Blade aerodynamic forces. According to a study on wind velocity profile law determinate the relationship of wind speed to height, and the aerodynamic forces on the tower has been solved. The dynamical response of numerical analysis of the offshore wind turbine was realized under combined aerodynamic loads and wave loads.In this paper, the dynamic response of a 5-MW offshore wind turbine was analyzed. The simulation experiment shows that the aerodynamic loads and wave loads are significant for structural design and stability of offshore wind turbines. The work provides an effective analysis method for the vibration and fatigue analysis of offshore wind turbine.