VERTICALLY 2D NEARSHORE CIRCULATION MODEL

Abstract

A two layer undertow model is developed which consists of surface and inner layer. The surface layer defines breaking wave dynamics and the inner layer defines the mean fiow(circulation) and turbulence fields. The interface between two layers is determined by time and depth averaging of the mean water level and wave height in the surf zone (interface model), in which Reynolds stresses are taken into consideration as well as radiation stresses. The system of equations in the inner layer is derived by time averaging the mass and momentum equations over one wave period. Time and space averaging of these equations in the surface layer defines the surface boundary conditions of the mean flow field in the inner layer. Turbulence in the inner layer is discribed by the standard k — e model. The numerical calculation method is also discussed and model calibration is performed by comparing with the experiments by Stive and Wind (1985).