Abstract In this paper, a modified MPS (Moving Particle Semi-Implicit) method is applied into 3D liquid sloshing to show its capability in modeling 3D sloshing flows. Violent sloshing flow in 3D rectangular is investigated. Furthermore, impact pressure value obtained by 2D and 3D simulation is compared, which indicates that 3D MPS simulation is able to produce smoother pressure field and thus makes better agreement with experiment than 2D MPS simulation. In addition, the snapshots of free surface deformation and velocity field are compared between experiment, 2D and 3D MPS simulation. Results show that the details of free surface deformation, such as the breaking region of the wave and the splash of liquid fluid can be capsized by 3D MPS method effectively.

ABSTRACT: The particle method is more feasible and effective than methods based on grid connection problems involving the violent free surface motions. This study modified MPS method to predict the impact pressure acting on the wall of partially filled with water rectangular tank. The numerical results compared with the experimental result by Kishev et al.(2006) for sloshing problems. And the time history of the pressure acting on the wall obtained the numerical simulation are shown to be in good agreement with experiment. INTRODUCTION The accurate prediction of highly nonlinear free-surface flows and the corresponding impact loads by fluid is very important in various oceanengineering applications including high waves, liquid sloshing, bow/deck slamming, or green waters. The numerical treatment of this kind of highly nonlinear free-surface behavior is usually very difficult and challenging due to the complexity of fully-nonlinear free-surface and body boundary conditions. In particular, how to trace free-surface particles in case of very violent motions, such as overturning, plunging, and splashing, is the most challenging task. There are several CFD techniques to handle such problems, i.e. SOLA-VOF (Hirt and Nichols, 1981), Level-Set (Sussman et al., 1994), Marker-Density function (MDF) (Miyata and Park, 1995) etc. However, there is a different approach without grid system, so-called particle method by use of kernel function and Lagrangian treatment of particles. For example, Koshizuka et al. (1998), Sueyoshi and Naito (2003) developed MPS (Moving Particle Semi-implicit) method, while Monaghan (1988) and Dalrymple and Rogers (2006) used SPH (Smoothed Particle Hydrodynamics). In MPS method, kernel-function-based difference algorithms are used for differentiation but kernel functions are directly differentiated in SPH method. Also for the pressure calculation the Poisson equation is used and solved iteratively at each time step in MPS method, while the state equation is used in SPH method.

ABSTRACT: The particle method (Moving Particle Semi-implicit method) is applied to violent free surface problems on marine engineering. The sloshing on very shallow depth condition and the very large motion of floating body with water invasion in waves are simulated successfully with it. These results show realistic behavior. INTRODUCTION After recent tragic losses of ships, many researchers have studied about the ship's damage stability and deck wetness. In these studies, they have always pointed out that behavior of water on the deck is very important. However violent free surface flow and dynamic effect of flow have hardly been considered. Almost studies of damage stability are stand on the quasi-static assumption about the behavior of water motion on the inner deck of ships. The deck wetness and the green water load acting on the structure have been treated with model experiments. In spite of an increase of computational resources in recent years, there has hardly been direct numerical simulation of these phenomena with CFD(Computational Fluid Dynamics) techniques. The reason of this exists as a difficulty in handling the violent free surface flow like fragmentation of fluid. Then VOF(Volume of Fluid Method) and its refined methods which use space fixed grid system has been used in several past studies. These methods are effective in handling violent free surface flow, but they include some of problems like numerical diffusion of free surface, stair effect, robustness of calculation and so on. Another difficulties of numerical simulation about problems exist in handling very large motion of boundary like the capsized hull. BEM(Boundary Element Method) with ALE(Arbitrary Lagrangian and Eulerian) grid has been used in researches of the numerical wave tank to simulate motion of floating body. However it is difficult to handle breaking waves, damaged hull's opening, etc. even if using ALE grid.