WAVE BREAKING IN A BOUSSINESQ MODEL WITH UNSTRUCTURED GRIDS

A model for solving the two-dimensional Boussinesq type equations including the breaking zone and the swash zone is presented. The enhanced Boussinesq equations by Madsen and Sørensen (1992) are discretised in space using an unstructured finite element technique. The inclusion of wave breaking is based on the surface roller concept and a new procedure for estimating the roller thickness is presented. The simulation of the moving shoreline is based on a technique, where the solid beach is replaced by a permeable beach with a very small porosity. Comparisons with physical experiments for the propagation, shoaling, breaking and runup of regular and irregular waves are presented. The application of the model for large coastal areas is illustrated with a simulation of wave propagation and breaking on a natural beach.