【摘要】 本文提出用简单Green函数1/r求解无航速的三维物体在水面、水下或在无界域中作各向振荡时水动力系数的数值方法。对于无穷远处扩散条件转换成辐射面条件的问题作了专门的考虑,即用圆柱将物体包围在其内部,该圆柱将流场分成内、外两部分,外部域中速度势的特征函数展开式与内部域中用Green公式求得的解相匹配。 根据本计算方法编制的程序对一些典型情况作了试算,其中包括在水面振荡的半球、方盒和圆盘的水动力系数曲线;水面及水底对圆球水动力系数的影响等。为考核本方法,与其它计算方法得到的结果作了比较。对方盒的三维结果与切片法作了比较。更多还原

【Abstract】 Based on the simple form of Green’s function, namely 1/r, a numerical method for calculating hydrodynamic coefficients of a three-dimensional body with arbitrary shape at zero speed performing harmonic oscillations of amall amplitude in free surface or underwater conditions is presented. Special consideration has been given to the radiation boundary conditions on a cylinder surrounding the body. In the outer region of the cylinder the velocity potential is described by an expansion of eigenfu- nctions with unknown coefficients, which are determined by matching the potentials on the interface with the inner region where the fluid motion is represented in terms of Green’s theorem and the simple Green’s function.Applications of the developed computer program are illustrated with several simple bodies oscillating in calm water. The influences of free surface and bottom surface on hydrodynamic coefficients of a sphere are examined, and comparison between the results of the present method and strip theory for a rectangular box are made.更多还原