Generalization of Shear Stress Distribution in Rectangular Compound Channels


Abstract: Experimental testing of 5 different types of boundary shear stress distribution in a symmetrical rectangular compound section channel was conducted. Shear stress distributions in the main channel and floodplains of 6 different rectangular compound cross-sections are presented. Numerical values of regression coefficients for the resulting 36 single-variable models representing 5 types of shear stress for each of the 6 cross-sections have been derived. All obtained statistics indicate that the derived regression models are quite good, and can effectively be used to estimate shear stresses with a high degree of reliability for constructed compound cross-sections using relative depth as the single independent variable. A generalized multiple-variable regression model has been derived to predict each of the 5 experimentally measured shear stresses as a function of 3 dimensionless parameters. These 3 dimensionless parameters combine both the depth and horizontal dimensions of the constructed cross-sections. All obtained regression statistics indicate the high reliability of the derived regression model in estimating presented shear stress types in an open channel of a rectangular compound cross-section. A single multi-variable regression model for estimating mean shear stress at the bottom of a rectangular compound cross-section has been formulated using average values of obtained regression coefficients of the multiple-variable regression model.

Keywords: Open channel, Compound cross-section, Shear stress generalization.

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