Calculation of Boudary Shear Stress in Open Channel Flow

Abstract

A mothod for calculating the velocity field in open channel flows for which boudary shear is an important factor. It is based on the assumption of a scalar eddy viscosity that is proportional to the shear velocity on the actual flow boundary. The 2-dimensional monentum equation produced by this turbulence closure is solved numerically. In a channel with a rectangular cross section, the flow structure depends on both the width- depth ratio and the wall-bed roughness ratio. For such channels, figures to evaluate the boundary shear stress distribution on the bed are provided. The validity of the theory, when applied to sediment transporting flows, is demonstrated using William's (1970) experimental data.