有限深水中沉井的水动力计算

本文提出用特征函数展开和匹配方法计算圆筒形沉井在有限深水中的流体动力系数,其中包括垂荡、纵荡(横荡)、纵摇(横摇)及纵荡与纵摇(横荡与横摇)偶合的附加质量和阻尼系数。用文中推导的公式编制的计算程序,对已发表的有三维源汇分布法计算和实验结果的例子的计算表明本方法有效。本方法的优点是计算速度大大快于其它数值方法,而且计算结果准确。文中对一些形状的沉井进行了计算,得到了其水动力系数的若干变化规律。本文对海洋工程中沉井这一结构物在波浪中的运动估算和结构设计提供了有效手段。

Calculation of Hydrodynamic Coefficients of A Caisson in Finite-Depth Waters

In this paper, eigenfunction expansion and matching technique are used to calculate added mass and damping of a caisson in finite-depth waters for surge, heave and pitch motion, as well as the coupling coefficient between surge and pitch. The theoretical method is checked for a case that the results of 3-D source distribution calculation and model experiment are available.The major advantage of the present method is that it requires very short computer time and less storage, while the results are still accurate compared with other numerical methods. A set of theoretical hydrodynamic coefficients for the caisson are presented. For the estimate of motions in waves and structural design of the caisson in the field of ocean engineering, the present paper is of particular significance.