The effect of beach reflection on undertow

Based on experiments, a model is introduced to calculate the vertical and horizontal distribution of undertow in the surf zone due to monochromatic and random wave attack for reflective beaches. The present model is a modification of the original model presented by Okayasu et al., [2] for natural, non-refiective beaches in which the wave set up, radiation stress and mass flux due to breaking waves are modified as described by Mehrdad and Neshaei [6] to include the effect of partially reflected waves. The results of experimental investigation and model development show that the existence of reflective conditions on beaches results in a reduction in the magnitude of undertow and modifies its distribution across the beach profile.