基于流函数理论的近海风机非线性波浪荷载计算

Calculation of the Nonlinear Wave Force of Offshore Wind Turbine Based on the Stream Function Wave Theory

近海风机多建于近海浅水区,波浪荷载非线性特性较为明显.基于流函数理论研究了高阶非线性波浪速度场和加速度场的特性.基于Morison方程和流函数理论计算了近海风机非线性波浪荷载,并研究了波浪自由面对近海风机非线性波浪荷载的影响,同时探讨了不同桩径时浅水区非线性波浪荷载的特性.为了验证计算结果的正确性和对比波浪的非线性特性,本文与线性波理论计算结果进行了对比,计算结果表明非线性荷载波浪峰值比线性波浪荷载峰值约大26.6%,波面变化影响将导致非线性波浪荷载计算结果产生14.7%的相对误差.在近海风机设计过程中,采用非线性波浪理论将得到更为准确的波浪荷载.

Offshore wind turbines are mainly built in shallow water,so the nonlinear characteristics of the wave forces are significant.The high order nonlinear wave velocity fields and acceleration fields were studied on the basis of the stream function wave theory.The nonlinear wave forces of offshore wind turbines were calculated with the Morison equation and the Stream Function Wave Theory.The free surface influences on the nonlinear wave forces of offshore wind turbines were studied.The characteristics of the nonlinear wave forces of piles of different diameters in shallow water were also investigated.To verify the correctness of the calculation results and compare the characteristics of the nonlinear wave force,the calculation results were compared with the linear wave calculation results.The results show that the maximum nonlinear wave force is 26.6% larger than the maximum linear wave force,and the free surface influences generate 14.7% relative errors.In offshore wind turbine design,the application of the nonlinear wave theory will lead to more accurate wave forces on offshore wind turbines.