A Three-Dimensional Numerical Simulation of Wave and Current Evolving Over a Submerged Shoal

Abstract

A three-dimensional numerical simulation of time-averaged wave-induced currents was performed, its results were compared with the results of a depth-integrated Boussinesq equation model And the differences were discussed in terms of wave height, instantaneous and mean free surface elevations, mean and time-averaged velocity fields, and turbulence parameters. For the three-dimensional simulation, an internal wave generation and a wave-absorbing sponge layer scheme, which can eliminate the influence of waves reflected from the wave source and wall boundaries toward the domain, were applied to the RANS equation model in a CFD code named FLUENT and the VOF model was utilized for the water surface In this study, two experiments involving wave-induced flows were simulated. First, to examine the wave-induced flows computed by the present model, we performed an existing two-dimensional experiment in which time-averaged mean motions induced by wave breaking were measured on a constant slope. Second, the breaking monochromatic wave case of Vincent and Briggs' experiments [Vincent and Briggs, 1989] was simulated in three dimensions using the present model. The experimental case presented a three-dimensional phenomenon in which a wave-induced jet-like current was generated and influenced the wave transformation over an elliptical submerged shoal. The computations agreed with the measurements and showed vertical distributions of the wave-induced currents over the shoal.