Wave shoaling over a submerged ramp: An experimental and numerical study

Shoaling in intermediate and shallow waters is a major process that occurs as the water wave travels toward the shore from deep waters. Evaluation of the appropriate shoaling coefficient (Ks) is essential in understanding the nearshore energy distribution and surf-zone dynamics. The value of Ks is underestimated using linear wave theory in shallow waters. The present work focused on the investigation of the shoaling coefficient through wave-flume experiments and numerical simulations. Furthermore, comparisons were made with nonlinear theories to bring out the range of applicability of theories. A submerged ramp was used in the wave-flume experiments to mimic the shoaling process. The nonlinearity in the unshoaled and shoaled-wave profiles were brought out using skewness and kurtosis. It was found that Cokelet's nonlinear theory agrees well with the measurements and computations. The comparative analysis of the experimental measurements with the numerical simulations suggests that the numerical model is a powerful tool to reproduce the wave-transformation process over sloping beds.