Numerical study of hydrodynamics around an artificial surf reef for São. Pedro do Estoril, Portugal

Abstract

This paper describes the application of the Boussinesq model (FUNWAVE 2D) to study the wave propagation in the vicinity of an artificial reef, to be implemented at S. Pedro do Estoril, Cascais, Portugal. First, the model was calibrated using measurements obtained in the 3D experiments performed at the wave tank of LNEC (scale 1:30). Then, an evaluation of the model performance is presented. For that, a comparison between numerical and physical model results in terms of the free surface elevation and wave heights is done for some incident wave conditions. It is shown that the numerical model predicts wave heights that are comparable to measurements if the wave breaking sub-model is properly tuned for dissipation over the artificial reef. Finally, the model was used to evaluate the reef performance in terms of the hydrodynamics around the reef, the wave breaking area and the surfability parameters. The numerical results confirm that the reef alters significantly the wave heights and wave directions in the zone, due refraction and diffraction effects. Best surf conditions (plunging waves with adequate values of the peel angle) occur with the reef for most of the tested conditions.