Three-dimensional numerical simulation of the hydrodynamics generated by a weak breaking tidal bore

A tidal bore is a positive surge propagating upstream as the tidal flow turns to rising in river mouths exhibiting a converging funnelled channel forms during low freshwater conditions. While some recent laboratory experiments brought new insights to the turbulent motion generated by tidal bores, a numerical model based upon the Navier-Stokes equations is proposed to investigate the complicated features of the flow. The goal of the present work is to simulate this three-dimensional unsteady twophase tidal bore motion. Therefore, we use a Synthetic Eddy Method to generate the turbulence and a Large Eddy Simulation method to gain a further understanding of the tidal bore processes. The numerical data are compared with some detailed laboratory data and the results are discussed. We aim at describing accurately the free-surface behaviour and the turbulent flow structure. This work is the first attempt to describe this complicated flow with three-dimensional numerical simulation.