Boundary Shear Stress in Smooth Trapezoidal Open Channel Flows

Semianalytical equations were derived to evaluate the mean boundary shear stress in smooth trapezoidal open channels using conformal mapping techniques. This process tends to a complicated function that should be simplified based on numerical integration. Also, based on a mathematical analysis, an approach that divides the flow area into subsections corresponding to the channel bed and sidewalls is presented. In particular, the hydraulic aspects of the best hydraulic trapezoidal sections were characterized to estimate the boundary shear stress distribution based on the exact form of the interface between adjacent subsections. To validate this approach, the analytical results were compared with the results of model experimentation performed in the present study. The analytical results agree well with the experimental measurements and the results of former investigations. DOI: 10.1061/(ASCE)HY.1943-7900.0000658. (C) 2013 American Society of Civil Engineers.