Solitary wave refraction and diffraction by submerged ramps in the presence of ambient current

Interaction of nonlinear waves with uneven bathymetry in coastal areas in the presence of ambient current is investigated by use of the computational fluid dynamics approach. The study includes refraction and diffraction of solitary waves over various bathymetry. A model based on the Navier-Stokes equations for laminar flow is developed for this purpose. The system of equations is solved by use of the finite volume approach. The model is solved both in two- and three-dimensions to study the wave diffraction and refraction problems, respectively. Emphasis is placed on the effect of the ambient current on the nonlinear wave diffraction and refraction in coastal areas by the submerged ramps. Various forms of currents, including following and opposing uniform currents across the water depth are considered. Results of the model are compared with existing experimental, analytical and numerical data, and overall, outstanding agreement is observed. Results are presented in the form of time series of surface elevation recorded at various gauges, and snapshots of the surface elevation in the entire domain. Discussion is provided on the effect of the ambient current on the wave field. It is found that the ambient current has significant effect on wave diffraction and refraction in coastal areas, and this effect appears to change nonlinearly with the current velocity and for various types and forms of waves.