Propagation of solitary waves over a bottom-mounted barrier

Abstract

The interactions between a solitary wave and a submerged, vertical, bottom-mounted barrier are investigated experimentally and numerically. Numerical results are calculated using the well-validated two-dimensional volume of fluid (VOF)-type model, named COBRAS (COrnell BReaking And Structure), based on the Reynolds-Averaged Navier–Stokes (RANS) equations and the non-linear k–ε turbulence closure model. Experiments are conducted to measure the free surface motion and velocity fields using a particle image velocimetry (PIV) system to provide data for model validation. Fairly good agreements at both the pre- and post-breaking stages are obtained. Then, the verified numerical results are employed to illustrate the free surface motion and the vortex evolution in detail. Wave breaking occurs in the direction opposite to that of the wave after a solitary wave propagates over the barrier. A local maximum value of turbulence intensity is observed for both experimental and numerical results at the impinging point of the breaking wave. An almost linear relationship between the maximum net force and the wave non-linearity is obtained. The effectiveness of the bottom-mounted barrier is estimated by evaluating the wave reflection, transmission, and dissipation coefficients using the energy integral method. Finally, the trajectories of marked fluid particles that are initially located around the barrier help understand the possible sediment transport.