非线性不规则波二阶分离模型

The second-order decomposition model of nonlinear irregular waves

基于二阶波势流理论,建立了一个非线性不规则波浪二阶分离模型.通过求解频域内一、二阶成分之间的传递函数,建立起二阶项求解关系式,将二阶项变换到与一阶项同一个傅里叶频域空间,采用Newton-Raphson迭代方法分别求解出目标波浪中一阶、二阶和频与二阶差频.利用所建立模型分别对规则波和二阶非线性不规则波进行了数值验证,并对波浪非线性的影响进行了分析,典型数值计算结果表明模型是有效的.

A new method to decompose the nonlinear irregular waves is proposed. The second-order P d otential flow theory is employed to construct the relation of the second-order items solution by eriving the transfer function between the first- and the second-order components. Target waves are decomposed into the first- and the second-order super-harmonic as well as the second-order sub- harmonic components by transferring them into an identical Fourier frequency-space and using a Newton-Raphson iteration method. In order to evaluate the present model, a variety of monochromatic waves and the second-order nonlinear irregular waves over a broad range of fre have been analyzed, and the effects on wave nonlinearity are analyzed. The experimental resu that the present method is reasonably effective for the wave decomposition. quencies Its show