Simulation of Nearshore Tsunami Breaking by Smoothed Particle Hydrodynamics Method

Abstract

This study applies the numerical model GPUSPH, an implementation of the weakly compressible smoothed particle hydrodynamics (SPH) method on graphics processing units, to simulate nearshore tsunami processes. Two sets of laboratory experiments that involve violent wave breaking are simulated by the three-dimensional numerical model. The first set of experiments addresses tsunamilike solitary wave breaking on and overtopping an impermeable seawall. Comparison with free-surface profiles and laboratory images shows that GPUSPH satisfactorily reproduces the complicated wave processes involving wave plunging, collapsing, splash-up, and overtopping. The other set of experiments investigates tsunamilike solitary wave breaking and inundation over shallow water reefs. The performance of GPUSPH is evaluated by comparing its results with (1) experimental data including free-surface measurements and cross-shore velocity profiles, and (2) published numerical results obtained in two mesh-based wave models: the nonhydrostatic wave model CCHE2D and the Boussinesq-type wave model FUNWAVE. The capability of GPUSPH to simulate nonlinear wave phenomena, such as wave shoaling, reflection, and refraction, is confirmed by comparing the wave field predicted by CCHE2D. Although all three models correctly simulate the solitary wave propagation offshore and the bore due to the broken wave run-up nearshore, GPUSPH outperforms CCHE2D and FUNWAVE in terms of resolving wave plunging and collapsing. The conducted two case studies show that the meshless SPH method is reliable for predicting tsunami breaking in the nearshore zone.