Study Of Dynamic Performance Of An Articulated Offshore Wind Turbine By CFD Method

A numerical water tank(JI-NWT-FOAM)based on the overset grid is developed by computational fluid dynamics(CFD)method.A wind-wave-current coupled dynamic response simulation software(JI-WWC-FOAM)is also developed by combining the JI-NWT-FOAM with the actuator line model(ALM).Dynamic performance of an 70 m articulated offshore wind turbine under different environmental loads is studied.This work has theoretical and engineering importance for simulation and forecast of dynamic response of articulated wind turbine.The JI-NWT-FOAM is written based on the Over Inter Dy FOAM solver of OpenFOAM.It uses the numerical wave-maker and sponge layer to make and mitigate wave respectively.Moreover,the 6Do F module is combined with the software to simulate dynamic response under the wave load.Wave making and mitigating function of JI-NWT-FOAM is validated by monitoring wave height in different locations.Furthermore,dynamic response of the articulated offshore wind turbine under wave load or wave-current load is simulated and analyzed.The aerodynamic module uses the ALM method and is coupled with the 6Do F module,so that the JI-WWC-FOAM software is written.Thrust and torque of NERL-5MW wind turbine under different wind speed is calculated by the aerodynamic module and compared with the FAST results for validation.Dynamic response of the articulated offshore wind turbine under different sea conditions is simulated.Without considering the two-phase effect,vortex induced motion(VIM)of the articulated offshore wind turbine is simulated based on the JI-NWT-FOAM.The k-?SST DDES turbulence model is used and different current speeds are studied.Results show that the JI-WWC-FOAM software and JI-NWT-FOAM are both validated and useful,while the flow field can be visualized in detail.Moreover,the70 m articulated offshore wind turbine has good dynamic performance,no matter under the wave load,current load,wave-current load or wind-wave-current load.Its dynamic response meets its design requirement.