Solitary Wave Breaking on Irregular 3D Bathymetry Using a Coupled Potential + Viscous Flow Model

Abstract

A three-dimensional (3D) coupled potential + viscous flow model based on a domain decomposition method is developed and applied to study shoaling and breaking of a solitary wave on a nonuniform bathymetry. The flow domain is decomposed into two subdomains separated by an interface: a wave generation and propagation subdomain modeled by a potential-flow (PF) solver and a shoaling and surf zone subdomain modeled by a Navier-Stokes equation (NSE) solver. The PF solver, based on a boundary-element method, is capable of modeling the motion of a piston wavemaker and the propagation of the resulting wave downstream. After the wave passes through the interface, it continues to propagate in the viscous-flow (NSE) subdomain, which is solved by a FEM. A free-surface capturing feature of the NSE solver allows simulation of wave breaking and the postbreaking behavior. Numerical results show good agreement with those of a large-scale wave-basin experiment of a solitary wave run-up on a 3D wedge. The simulation shows that breaking criteria and categorization for plane slopes do not apply to this particular bathymetry. The velocity and vorticity patterns during wave breaking are also examined to demonstrate the capabilities of the viscous-flow solver.