Coupled wind-wave time domain analysis of floating offshore wind turbine based on Computational Fluid Dynamics method

Abstract

As offshore wind farms are extending into the deep sea around the world, the coupled aerodynamic and hydrodynamic time domain analysis of floating offshore wind turbine is of both profound academic interests and important practical interests. In this work, one typical tension leg platform of 5 MW wind turbine system has been chosen to the objective. The aerodynamic loads of the NREL 5 MW offshore wind turbine have been simulated based on Navier-Stokes equations and renormalization group (RNG) k-ε turbulence mode, which is suitable for the analysis of rotational flow field near wind turbine blades. The hydrodynamic loads of the floating wind turbine platform have been simulated by viscous numerical flume based on volume-of-fluid method. The dynamic responses of the floating wind turbine system could be obtained by solving the dynamic equations of the floating system under typical coupled wind-wave sea cases, and the motion of the floating platform under different time steps would be simulated by advanced sliding mesh technique. As a result, the fluid-structure interactions between the floating wind turbine structure and the coupled wind-wave flow field have been successfully simulated. Furthermore, the availability of the coupled numerical method has been verified by comparing the numerical results with corresponding scale model test data.