Guoming Ling, Junichi Matsumoto, Kazuo Kashiyama

This paper describes a 2D-3D hybrid model for tsunami simulations that uses an overlapping method based on an arbitrary grid. A 2D model is used to simulate wave propagation from the source area to the offshore area, and a 3D model is then used to simulate the free surface flow around structures in coastal areas. An overlapping method that satisfies the conservation and compatibility conditions is developed to couple the two models. The shallow water equations are applied for the 2D model, and the Navier-Stokes equations and continuity equations are applied for the flow field of the 3D model. The Allen-Cahn equation is applied for the interface-capturing method of the 3D model. The stabilized finite element method is applied for the spatial discretization and the Crank-Nicolson method is used for the temporal discretization of the governing equations. The model is verified and validated through several numerical analysis examples.