大型补给舰船液舱晃荡载荷计算方法

随着补给舰船的大型化,补给舰船中的液舱晃荡问题开始凸显。为给大型补给舰船的液舱结构设计提供方便、可靠的晃荡载荷输入,基于改进的VOF法,以Youngs法重构自由液面,结合部分单元参数概念,提出了一种精度更高且数值稳定的、处理非矩形复杂舱室边界晃荡载荷的计算方法。通过对不同装载情况的液舱晃荡进行数值分析,并与Hirt-Nichols算法以及实验结果进行对比,证明该方法可有效改进自由表面的模拟效果,提高舱室内部速度、加速度和压力的预报精度。网格敏感性分析证明该方法的数值稳定性较好,较粗的网格也能达到较高的精度。所建立的晃荡载荷计算方法可用于对补给舰船的液舱晃荡设计载荷进行快速、准确的预报。

Calculation Procedure of Sloshing Loads for Large-Scale Depot Ships

With the ever-expanding size of depot ships, the problem of liquid sloshing in cargo tanks becomes increasingly highlighted. In order to provide reliable reference data during the design process of tank structures for large-scale depot ships, a calculation procedure of sloshing loads with high precision and numerical stability is proposed in this paper. This procedure uses the improved VOF method, namely the Youngs method, to reconstruct the free surface and incorporates partial cell parameters to deal with com- plex non-rectangle liquid tank boundaries. Experiments with different filling ratio were conducted, and the resuhs obtained with this procedure and those with Hirt-Nichols method were compared. It has been found out that the method suggested here could improve the free surface simulation speed as well as the estimation accuracy of the internal velocity, acceleration and pressure. Also, a separate cell sensibility analysis successfully validates the method/s reliability with coarse grids, which suggests that it could be also applied to the quick estimation of design sloshing loads