液舱内流体晃荡特性数值研究

本文利用VOF法对矩形液舱内液体晃荡进行数值计算。首先对舱内无任何隔板时液体晃荡作了模拟,并与相关文献中的实验结果进行了比较;然后在舱底中间设置一道不同形式的防晃隔板,对液体晃荡进行了计算。从结算结果看,本文提出的方法可以用于分析液舱内液体的运动和载荷,为设计合理的液舱结构形式提供理论依据。

A Numerical Study on Sloshing Phenomena in a Liquid Tank

A numerical simulation method is presented in the present paper to simulate the sloshing phenomenon in a liquid tank. The liquid motions are described with Navier Stokes equations rather than Laplace equation of the potential theory. The profile of liquid surface is reconstructed by a function of the volume of fluid in each computational step on the basis of the volume of fluid method (VOF). The governing equations are discretized by difference method with staggered girds as used in the MAC method, and are solved by super over relax (SOR) method. The present simulation method is applied to a partly filled rectangular water tank with or without a bottom baffle, to predict the sloshing phenomena caused by a prescribed pitch excitation. The numerical predictions for the case without a bottom baffle are compared with the experimental results published in . The comparison shows that the calculated time histories of the pressures at different positions on the tank wall are quite similar to the experimental measurements. The influence of the baffle, with either "|" or "T" shape installed at the bottom of the tank, on the liquid motions is also studied. The calculated pressures acting on the walls of three different tanks (without baffle, with "|" baffle, and with "T" baffle) excited by the same excitation are compared with each other. The corresponding stream trace images are also illustrated. It can be seen that the inside baffle greatly reduces the impulse pressures in comparison with the case of the tank without a baffle. The stream trace images show that under the prescribed pitch excitation, the top impact happens in the tank without a baffle, however does not appear in the tanks with a baffle. In reducing sloshing motions, the baffle with "T" shape is better than that of "|" shape. Conclusively, the present numerical method may help to predict the features of sloshing in liquid tanks and assist designing of container structure.