Nearshore Circulations under Sea Breeze Conditions and Wave-current Interactions in the Surf Zone

Numerical models for nearshore circulation patterns in the surf zone were developed and applied to an observed condition subjected to a sea breeze environment. Bottom topography and input waves were derived from observed data to predict surf zone circulation as a function of time of day. It was found that many features observed in the surf zone were modeled but wave-current interactions are known to be important. Wave-current interactions were modeled for shallow water assuming a two-dimensional motion which included rip current and lonshore current components. The refraction effects caused by even small currents produce major changes in the wave induced driving forces in the surf zone which leads to the prediction of entirely different rip-current patterns when wave-current interactions are considered. Numerical results are presented and a discussion of the numerical techniques is included. A review of water wave theories to include mass transport, vorticity and current was made for a vertical section in shallow water of constant depth.