Wave-Energy Dissipation and Wave Setup Caused by Entrained Air Bubbles in Plunging Wave Breaking

In this study, a simple air-bubble model was developed for unidirectional, homogeneous, plunging-wave propagation over a sloping beach to calculate wave height and wave setup in the surf zone. Two parameters used in the model, the reference void fraction and the decay factor, were determined by comparing model results with experimental results, and they are functions of the local wave height and the relative distance from the breaking point, respectively. Moreover, a free parameter of the model was calculated using the best fit of a curve based on experimental data from different flow regimes of plunging wave breaking. The results of the air-bubble model were compared with laboratory data and the computed results showed good agreement, except for some discrepancies in the vicinity of the breaking point and near the shoreline. (C) 2014 American Society of Civil Engineers.