VELOCITY FIELD UNDER PLUNGING WAVES

In order to clarify the characteristics of the velocity field in the surf zone, three sets of detailed and precise two dimensional laboratory experiments were performed. Spatial distributions and time histories of velocity were measured by using a hot film velocimeter with a split type probe or a two components laser doppler velocimeter for regular wave conditions. Typical plunging breakers were formed during the experiments. Based on the experimental results, a model was investigated in order to estimate the two dimensional distribution of the on-offshore steady current below the trough level.