CHAPTER 43 A Two-Dimensional Surf Zone Model Based on the Boussinesq Equations

A simple approach to wave breaking using the concept of surface rollers is intro-duced in a two-dimensional Boussinesq model. A surface roller represents a passive bulk of water riding on the front of a breaking wave and the vertical redistribution of momemtum associated with the formation and change of surface rollers leads to additional terms in the Boussinesq equations. A simple geometrical method is used for the determination of the shape and location of these rollers at each time step in the simulation. This automatically results in a time-varying break point position in the case of irregular waves. Furthermore, breaking may well cease for example when waves reach a trough inshore of a bar. Comparison between one-dimensional simulations and experiments shows good agreement for the variation of wave height and mean water surface as well as surface elevation time series throughout the surf zone for both regular and irregular waves. Simulations in two horizontal dimensions are still at the initial stage. A sample simulation is shown