A series of numerical simulations were performed to explore the influences of filling level, excitation frequency and amplitude on liquid sloshing by using the open source Computational Fluid Dynamics toolbox OpenFOAM (Open Field Operation and Manipulation), which was fully validated by the experimental data. The results show that the dynamic impact pressure is proportional to the external excitation amplitude only in non-resonance frequency ranges. Pressure-frequency response curves demonstrate a transition process from a 'soft-spring' response to a 'hard-spring' response following the changes of the filling level. Such a transition process is found to be dominated by the ratio of the filling level to tank length and the critical value can be obtained. It is also found that wave breaking influences the period of sloshing wave in tanks and ultimately alters the resonance frequency from the linear theory.

A series of numerical simulations were performed to investigate the influences of storage vessels shapes on sloshing dynamics under horizontal excitation by employing the open source code OpenFOAM, which has been extensively validated by experimental data for the sloshing flow problem. The results show that the membrane liquefied natural gas (LNG) tanks are subject to lower impact pressure than the cylindrical, rectangular and spherical tanks with the same volume of liquid and the overall tank dimensions, as the slope at the storage vessels bottom changes the flow direction of the liquid and therefore reduces the impact on the vertical wall. In the cylindrical and spherical tanks, higher impact pressure was found on the wall directly opposite to the excitation direction and the maximum impact point will shift away from the external excitation direction as the wave breaks up violently until a quasi-steady state of the sloshing wave rotating along the side wall is reached. The curved surface of the spherical tank could also help reduce the impact pressure when compared with the cylindrical tank.