A CFD simulation of 3D tsunami-like solitary wave propagation in a reef-lagoon-channel coastal system

Abstract

There has been significant interest in post-tsunami surveys regarding how effective fringing reefs are at protecting coastlines from inundation caused by tsunamis. Limited attention has been given to the wave transformation characteristics and wave run-up dynamics within a complex reef-lagoon-channel system compared to the extensively studied two-dimensional horizontal fringing reefs. In response to this research gap, a three-dimensional numerical wave tank has been created, incorporating the incompressible Reynolds-averaged Navier-Stokes equations accompanied with k-ω SST turbulence model. The volume of fluid (VOF) strategy is employed to track the free surface, accompanied by advanced grid cascading encryption technology. Laboratory measurements (Swigler, 2009; Briggs et al., 1995) of the waves are utilized for model validation. The influence of incident wave height, reef flat submergence, fore-reef slope, and channel width on wave propagation characteristics were examined. The results reveal that the relative run-up decreases with larger wave heights and decreases near channels as reef flat submergences rise. Initially, smaller channels reduce relative run-up, but it increases again with widening, shifting the maximum relative run-up location away from the channel, while fore-reef slope changes minimally affect run-up.