有限水深二维绕射问题的二阶速度势和水动力

SECOND ORDER POTENTIALS AND FORCES FOR TWO DIMENSION DIFFRACTION PROBLEM OF FINITE WATER DEPTH

本文给出有限水深二维物体二阶绕射势在外域中的解析表达式，从而准确满足二阶绕射势的辐射条件。二阶绕射势在内域自由表面上的边界条件则由一阶势的数值微分求得。然后对内域用简单Ｇｒｅｅｎ函数法求得二阶绕射势。本文对二维浮体和潜体在不同水深和潜深情况下的绕射问题进行了计算，求得了二阶绕射势和二阶定常及倍频波浪力。

In this paper, an analytical solution in the outer region of finite water depth is derived for the second order diffraction potential of two dinercion substarces,which gives a clear physical meaning of the wave transmission and reflection characteristic in the far field.A numerical method simple Greens function technique for calculating the second order potential in the inner region is also described. Numerical results are provided for the second order wave forces on a semi submerged and a full swbmerged cylinder. It is found that the contribution of second order diffraction potential to second order wave forces is important, The effect of water depth and submerged depth on the wave force is also discussed.