Abstract:  In recent years，the structural design of liquid cargo ships has been focused on the liquid sloshing in
tanks，which involves the high non-linearity problem related to the large amplitude motion of free liquid surface and therefore causes some difficulties in Euler numerical simulation depending upon spatial topological meshes． In this paper，the liquid sloshing of a tank at different filling ratios is numerically simulated by means of the Lagrangian view-based finite point method (FPM)，and the numerical results are compared with the experimental ones． The results show that when the excitation frequency is consistent with the natural frequency of the tank，the fluid sloshing is severer; and that，at different filling ratios，the fluid in the tank with a high filling ratio will flow with moderate deformations due to the inhibition of bulkheads． Moreover，the FPM can effectively and accurately simulate the violent changes of the liquid sloshing of the tank at different filling ratios under the multi-frequency excitation，and the simulation results accord well with the experimental phenomena． Meanwhile，an impact pressure on the bulkheads is observed and the calculated values obtained through the FPM are consistent with the measured pressure
curves． It is，therefore，found that the FPM performs accurate simulations on the two-dimensional liquid sloshing in the tank under different conditions，which effectively verifies the reliability of the FPM．

Key words:  liquid sloshing in tanks, Lagrangian view, finite point method, moving least square, Poisson equation