In this paper, a numerical technique to treat thin plates in a tank for moving particle semi-implicit (MPS) method is proposed. The MPS method is a robust and reasonable solver to compute complicated free surface flows but it usually requires some thickness of solid wall boundaries. The proposed technique uses the effect of ghost particles and the normal vector on the solid body surface to represent the thin plate condition without high spatial resolution.
Ships and marine structures are usually equipped with tanks to storage liquid cargo or fuel. Some times, such liquid cargoes with free surface causes sloshing problem, which is harmful to the safety of the operation. In a partially filled tank, the fluid motion is free surface flow, which is a very complicated moving boundary problem. The pressure in the tank dynamically changes and interact with structure and ship motions. In some serious cases the impulsive fluid pressure acting on the tank's wall causes damages of the structure. Nowadays, there are many kinds of techniques to treat sloshing problems. The particle method is one of gridless methods, which can compute extremely large deformation of free surface. The most popular one is smoothed particle hydrodynamics (SPH) technique for incompressible flow (Monaghan, 1994). In the field of naval and marine engineering, some applications of SPH method (Fontaine et al., 2000, Landrini et al., 2002, Souto and Pavon, 2003) has been already carried out and some evolved SPH methods are developed recent years(Colagrossi et al, 2003 and Khayyer et al, 2008). On the other hand, moving particle semi-implicit (MPS) method (Koshizuka, 1996, 1998) is also a suitable method for computation of incompressible flows with complicated free surface. Sueyoshi and Naito(2003) showed some numerical applications to some marine engineering problems by using the MPS method. These particle methods have availability to compute complicated free surface problems.