Effects of nonlinear inertial forces on nearshore currents

A perturbation method is developed to investigate the effects of nonlinear inertial forces on breaking-wave-induced nearshore currents. Obliquely incident waves are considered and the bottom topography varies periodically in the shoreline direction. For simplicity, lateral turbulent mixing is ignored. Numerical examples are given for a specified bottom topography with various angles of incidence and surf zone width. The nearshore currents of interest mainly belong to the meandering type. When the nonlinear terms are included, there appears an advective shift as well as an amplitude reduction in the current pattern.