无限水深下波浪与二维水面物体作用的简单格林函数方法

A BEM WITH SIMPLE GREEN’S FUNCTION FOR WAVE INTERACTION WITH A 2D BODY AT THE SURFACE OF INFINITE WATER

针对无限水深下波浪与二维水面物体相互作用问题,传统的波浪格林函数形式复杂、计算缓慢,为了提高计算效率和计算精度,将流域分为物体周围的内域及远离物体的外域,内域采用简单格林函数法,外域采用多极子展开方法,通过内外域边界匹配,耦合求解得到流域中任意一点的速度势,并可计算物体在波浪作用下的波浪激振力、附加质量、辐射阻尼及透射和反射系数。应用该方法计算了二维水面漂浮半圆和水面漂浮方箱的算例,数值计算结果表明,该方法可以方便、准确、快速地计算无限水深下波浪与任意漂浮物体的作用问题。

To understand the interaction of waves with a two-dimensional surface body in infinite water depth,the traditional wave Green’s function has complex form and slow calculation.In order to improve the calculation efficiency and accuracy,the watershed was divided into inner domain around the object and outer domain far away from the object.Simple Green’s function method was adopted in the inner domain,and multi-pole expansion method was adopted in the outer domain.The velocity potential of any point in the watershed can be obtained through coupling solution by matching inner and outer domain boundaries.The wave excitation force,additional mass,radiation damping and transmission and reflection coefficients of the object under wave action can also be calculated.The method was applied to calculate two-dimensional water surface floating semicircle and water surface floating square box,and the numerical results show that the method can conveniently,accurately and quickly calculate the interaction between waves and arbitrary floating objects in infinite water depth.