A three-dimensional non-hydrostatic model for tsunami waves generated by submarine landslides

A three-dimensional (3D) non-hydrostatic model for simulating nonlinear and dispersive waves is extended to compute submarine-landslide-generated waves. The model uses a projection method to solve the 3D Navier-Stokes equations on a 3D grid system built from a two-dimensional (2D) horizontal mesh by adding several horizontal layers in the vertical direction. The free surface is efficiently captured by the so-called free surface equation. The bottom movement is incorporated in the model by specifying the kinematic boundary condition at the impermeable bottom. The extension does not alter the property of the discretized Poisson equation for non-hydrostatic pressure correction terms. Thus, it can be also solved efficiently by the preconditioned conjugate gradient method. A wide range of tests including 2D and 3D landslide waves are simulated. Comparisons between numerical results and experimental data and/or other model results are presented. It is found that a good agreement has been obtained for a range of landslide waves using a very small number of horizontal layers (e.g. three or five layers) and the proposed model can be considered as an attractive alternative to simulating submarine-landslide-generated waves