FIELD OBSERVATION ON SAND RIPPLES UNDER ROUGH SEA STATE

Abstract

The process of sediment sorting under rough sea state was made clear in the cross-shore direction. Field observation reveals that ripples can be formed under high shear stress in which the Shields number is more than two. The plane bed condition is observed at narrow area of wave breaking. Strong undertow distorts the shape of ripples. The criterion of bed configuration given by Kaneko (1981) is good agreement with the field data which were rearranged with significant wave characteristics. The criterion of Komar and Miller (1975) is also applicable with mean wave ones.