Boundary shear stress in asymmetric rectangular compound channels

Abstract

A series of nine experiments was performed in a physical model of an asymmetric compound channel to quantify the boundary shear stress at the interface of the bed of a main channel and floodplain. Commonly used equations of shear stress distributions across the bottoms of the main channel and floodplain interfaces were analyzed and tested for various types of asymmetric compound channels and their flow conditions. The lateral momentum transfer between the deep main channel and the adjoining shallow floodplains was found to greatly affect the shear stress distribution at the bottoms of the main channel and the flood plain subsections. Different dimensionless ratios of shear stress distributions were obtained and related to the relevant parameters. Some important results concerning the uniformity of the shear stress distribution, which is significant in sediment-laden rivers to state the possible locations of erosion and deposition, are presented.