Numerical study of Bragg reflection of regular water waves over fringing reefs based on a Boussinesq model

Abstract

The Bragg reflection of regular waves over fringing reefs is studied using a shock-capturing Boussinesq model FUNWAVE-TVD. Model validation shows the present model can reasonably reproduce regular wave processes over a reef bathymetry with a proper grid size and Bragg reflection induced by sinusoidal and rectified cosinoidal bars set on the horizontal bottom. Numerical results clearly show the sinusoidal bars set on the reef flat can reduce the maximum run-up height and confirm the Bragg resonance effect over the reef bathymetry. The basic effects of parameters of sinusoidal bars (i.e., the number of bars and the relative bar height) on the Bragg reflection of regular waves over fringing reefs are slightly different to the ones over the horizontal bottom. Moreover, Bragg resonance can also be observed over the rectified cosinoidal bars set on the reef flat. But the effect of the rectified cosinoidal bars is not as significant as the sinusoidal bars. The results presented in this paper preliminarily reveal the feasibility of Bragg reflection of water waves in reef environment and further investigation of the Bragg reflections of irregular waves over fringing reefs can be expected.