Tsunami overflow is complicated phenomena to include various kinds of debris. In experiments, it spends for long time and is not economical. Therefore, a high-precision numerical simulation is required to understand interaction between fluids and solids. MPS (Moving Particle Semi-implicit) method is one of Lagrangian method. It is possible to simulate an incompressible fluid with complicated free water surface and to analyze multi-physics. However, because both fluids and solids are considered particles, an enormous amount of particle is necessary in the case of a large-scale simulation. Especially, because there is need for using many particles on wall boundary, both time and labor are required. In this study, we propose wall boundary model of polygon type and reduce the time cost. Further, we try to simulate complicated phenomena using the polygon boundary and prove appropriate results.
