A Study on Estimation Method of Sloshing Loads on Actual Ship Tanks

一艘船在海浪中以六个自由度随机运动。因此，船舶运动引起的船舱内流体的晃动行为应视为一种三维的、非线性的现象，从而成为理性分析中一个相当复杂的问题。这项工作的目的是建立一种合理的方法来估算实际船舶液舱的晃动载荷。研究结论如下：1.研究结果。提出了一种分析三维晃动问题的方法。在该方法中，引入了一种利用摄动展开简化边界元方法的算法，该算法考虑了船舶的所有六个自由度的运动。使用这种方法，可以分析在规则波或不规则波(即海浪)中前进的船舶液舱内的晃动现象。提出了一种计算具有绝对随机变量的非线性响应极大值的概率分布的方法。利用这种方法，可以对满载的棱柱形储罐壁面上产生的动水压力进行统计预测。作为文[1]和[2]计算的应用实例，给出了一艘巨型油轮棱柱体储罐的各种数值模拟结果。结果表明，综合运用上述计算方法，可以估算实际船舶液舱的晃动载荷。

A ship in sea waves behaves randomly in six degrees of freedom. Therefore, the sloshing behavior of fluids in ship tanks, which is excited by ship motions, should be treated as a three-dimensional and non-linear phenomenon, then it becomes a fairly complicated problem in the rational analysis. It is the purpose of this work to establish a rational method for estimation of the sloshing loads on actual ship tanks. The conclusions are as follows.1. A method is proposed for analysis of a three-dimentional sloshing problem. In this method, an algorithm of the boundary element method which is simplified by use of perturbation expansion is introduced, and all of the ship motions which have six degrees of freedom is considered. Using this method, it is possible to analyze a sloshing phenomenon in tanks on a ship which advances in regular waves or irregular waves(i.e. sea waves).2. A method is proposed for calculations of the probability distribution of the maxima of non-linear response with absolutes of random variables. Using this method, it is possible to make a statistical prediction of the hydrodynamic pressure induced on the walls of the full-filled prismatic tanks.3. The results of various numerical simulations for prismatic tanks on a gigantic oil tanker are illustrated as application examples of the calculations by 1. and 2.. As a result, it is recognized that we can estimate the sloshing loads on actual ship tanks by application of combined use of preceding calculation methods.