Numerical simulation of wave transformation across the surf zone over a steep bottom

The combined effect of wave shoaling, breaking and energy dissipation on a steep sloping bottom was developed. Based on the conservation principle of wave motion, a combined shoaling and bottom slope coefficient is included in the mild-slope equation (MSE), which is derived as a function of the bottom slope perturbed to the third-order. The model incorporates the nonlinear shoaling coefficient and energy dissipation factor due to wave breaking to improve the accuracy of the numerical simulation prior to wave breaking and in the surf zone over a steep bottom. The model validity is verified by comparison with laboratory experiments for waves traveling over two steep sloping beaches and a bar/step-type beach profile.

► We present a numerical model for wave propagating over a steep bottom.
► A perturbation method is used to derive expression of nonlinear shoaling coefficient in terms of bottom slope to third order.
► Model validity is verified by comparison with laboratory experiments for steep bottoms.