Numerical Simulation of Tsunami Force Acting on Vertical Walls

Abstract

A tsunami can cause enormous loss of life and property in coastal communities. Therefore, when designing coastal infrastructures for protection against a tsunami, estimation of the tsunami force on a vertical wall is necessary. This work investigates the tsunami force on a vertical wall for different wave (tsunami) heights and cross-shore locations of vertical walls by using hydrodynamic numerical model simulations. The numerical model is based on the Reynolds-averaged Navier-Stokes equation, k-epsilon turbulent closure, and volume of fluid method to simulate the hydrodynamic forces induced by a tsunami. First, the numerical model was validated using physical modeling data from a large-scale laboratory experiment by comparing hydrodynamic parameters. Then, the numerical simulations were repeated for combinations of five wave heights and 28 cross-shore locations of vertical walls. For fixed cross shore locations, the tsunami force increased in proportion to the wave height. For constant wave heights, the tsunami force exponentially decreased as the distance of the vertical wall from the shore increased. Finally, a predictive formula of the tsunami force on a vertical wall was proposed in terms of wave heights and the cross-shore locations of vertical walls based on a regression analysis for the numerical simulation results.