Numerical computation of the nearshore current considering wave-current interactions at Gangjeong coastal area, Jeju Island, Korea

Abstract

Nearshore current phenomena have considerable effects on sediment transport, erosion and accumulation as the water circulation system within nearshore regions is generated and changed by wave-current interactions. Therefore, predicting such nearshore current is very important. In this study, by considering the wave-current interactions and vertical variation of currents, nearshore current phenomena can be more accurately computed. A nonlinear parabolic mild slope equation and a quasi-3D equation are used in wave deformation and circulation analyses, respectively. Velocities caused by tide are also applied to boundaries using the volume flux, so that more exact numerical analyses can be performed. The numerical model is verified through two test cases, and good agreements are obtained. To investigate the actual flow tendency, time dependent nearshore currents are computed at the Gangjeong coastal area, Jeju, Korea. From the numerical results, important phenomena for the nearshore current such as the wave-current interactions, longshore current, and rip-current are well captured.