Modelling secondary cells and sediment transport in rectangular channels

Abstract

Modelling the boundary shear stress distribution using a depth-averaged approach such as the Shiono and Knight method can give inaccurate results due to poor representation of secondary current cells. The perturbations in the experimental boundary shear stress distributions were analysed to develop an improved modelling approach to capture the secondary current cells effects. This approach is applied to a variety of experimental data, and accurate results were obtained for both the depth-averaged velocity and boundary shear stress distributions. The outcome indicates that the standard calculation of the boundary shear stress can overestimate the shear values. The proposed modelling approach is applied to compute sediment transport based on equations using the boundary shear stress. The analytical sediment transport results could not predict the experimental values despite the improvement in the boundary shear stress distribution, mainly due to limitations of the sediment equations.