Numerical Investigation Of Tank Sloshing Based On OpenFOAM

Liquid sloshing is a free surface fluctuation phenomena in partial filled liquid tank.This kind of free surface flow phenomena are very common,such as the liquid fuels in spacecraft,road transport vehicle,VLCC,LNG,LPG or huge tank under seismic wave.The liquid in the tank will behave complex sloshing phenomenon with the movement of the whole structure,forming phenomenon such as standing wave,hydraulic jump,splash and so on.The sloshing impact load has great effect on the tank structure and the overall motion of the structure.The problem of sloshing has become one of the important safety assessment index of ship.Based on the comprehensive summary of the research and development of liquid sloshing.This study is focused on following aspects:In chapter Ⅱ,the two-phase flow model based on VOF method is first discussed,the control equation,finite volume discretization and the uncoupling of pressure and velocity are presented,and then the applicability of OpenFOAM dynamic mesh on the tank sloshing is investigated.The approximate super-resonance analytical solution of nonlinear rolling motion is derived for the study of characteristic of sloshing under nonlinear rolling motion.Based on the discussion all above,the method of numerical simulation of sloshing in OpenFOAM is presented.In chapter Ⅲ,Firstly,the comparisons of the numerical results with analytical solution and experimental results are performed,the effectiveness of OpenFOAM simulation method in calculation of wave elevation,free surface capturing,the calculation of pressure distribution and the time history of pressure on the tank wall is verified.Moreover,simulations of sloshing characteristics under the coupling excitations of swaying and surging are presented,results show that under coupling excitations of swaying and surging,the wave elevation of free surface is higher than the sum of ones under swaying and surging alone,it is concluded that sloshing will perform new characteristics under coupling excitations.Furthermore,based on the approximate super-resonance analytical solution of nonlinear rolling motion,simulations of sloshing characteristics under the super-resonance rolling motion is performed,results show that under super-harmonic rolling,the characteristics of the free surface are characterized by strong nonlinear phenomena,such as turning up and breaking.In addition,the dynamic pressure on the tank wall shows the characteristics of multiple peaks and its peak value is much larger than one for harmonic excitation.In particular,the resonance phenomenon happens when the natural frequency of the partial filled tank is equal to difference frequency of two harmonic waves in super-harmonic rolling motion.In chapter IV,the work of this paper is summarized and the fut ure of the study of sloshing phenomena are prospected.