Correlation and distribution of shear stress for turbulent flow in a smooth rectangular open channel

Abstract

Calculation of shear stresses in open channel flow is very important in civil engineering applications such as structural design, determination of velocity distribution and sediment transport. It is argued in literature that the velocity distribution equations for pipe flow may be used in open-channel flow analysis. However, due to irregular boundary sheer stress, this claim seems to be unreasonable and the irregularities should be taken into consideration. In this study, wall shear stresses for turbulent flow in rectangular open channel are investigated. Using mean velocity measurements and assuming validity of the logarithmic velocity distribution perpendicular to wetted perimeter, dimensionless shear stresses in the unified velocity distribution are determined.A semi-theoretical method is applied for the solutions of non-linear equations.A shear stress distribution equation is proposed to calculate irregular boundary shear stresses on the wall and bed in smooth rectangular channels.