Research On Nearshore Currents With Wave-current Interaction

Wave is one of the most important dynamics in the nearshore area. When the wave propagates toward the coastal area, it changes greatly for the influence of tide and the sea bottom, finally it breaks in the surf zone and contributes the longshore current and rip current. The wave-induced nearshore currents play a great pole in the nearshore current field and it is the key dynamics contributing the longshore sediment transport and leading to the beach evolution. Recently, with the increasingly heavy sea pollution hazard and the growing research on the pollution transportation, people realized the the great importance of nearshore circulations induced by wave-breaking. With the development of beach tourism, wave-induced nearshore currents, especially rip current, have been the concerning of the international research.Based on the great many essays, the paper summarized various numerical methods on nearshore circulation. In the this essay, firstly, we introduced a quasi-3d nearshore current model which is based on radiation stress conception . The nearshore model is coupled with the REF/DIF1 wave model and includes the influence of the wave-current interaction, which makes great progress than the former models.In the model application, the paper studied the effecting factors in the longshore current and rip current respectively.First, the paper modeled the regular wave-induced longshore current under various slope beach and wave climates using the model. Compared with two lab experiment, we studied the influence of incident wave angle, wave height, wave period and the bottom friction on the longshore current. Further, we study the longshore current on a cosin-squred beach under the normal wave incidence.Second, we discussed the importance of wave-current interaction. Combined with the lab experiment, the numerical model is applied to wave-induced nearshore currents on a fixed tri-cuspate beach. A parameter study demonstrates the sensitivity of nearshore flow patterns to changes in relative cusp height, angle of wave incidence, bed roughness, offshore wave height.