Numerical Simulation of 3D Flow and Topography Change in Harbor Caused by Tsunami

Abstract

Topography change in a harbor caused by tsunami affects serious damage to the harbor functions. In this paper, a non-hydrostatic three-dimensional (3D) flow and topography change model was proposed in order to predict the topography change with high accuracy. In the proposed model, the 3D Reynolds-Averaged Navier-Stokes (RANS) equations on the Cartesian coordinate system was used for flow and the linear k-e turbulence model was adopted for the evaluation of the eddy viscosity coefficient. In the topography change model, bed-load and suspended-load transport were considered. Moreover, the Fractional Area/Volume Obstacle Representation (FAVOR) method, which has the ability to impose boundary conditions smoothly at complex boundaries, was introduced into the governing equations, and the fifth-order Weighted Essentially Non-Oscillatory (WENO) scheme was applied to discretize advection terms of the governing equations. In order to verify the validity of the proposed model, it was applied to a large-scale experiment with a scale model of harbor. Comparisons between the simulated results and experimental ones proved that the model was able to reproduce the topography change around the harbor with sufficient accuracy, especially the sediment deposition in the center of the harbor and the scouring near the breakwaters.