Author(s): Nicolas De Cacqueray; David M. Hargreaves; Hervé P. Morvan
Keywords: Bed; channel; computational; division; fluid dynamics; rectangular channel; shear; wall
Abstract: The assumption of uniform flow permits the computation of the bed mean shear stress in open channels from the knowledge of the bed slope, hydraulic radius and fluid density alone. It is however important to distinguish between bank and bed shear values, in particular for sediment transport applications and research on this issue has been ongoing since the 1930s. This line of work was revived recently by Yang and Lim (1997) and Guo and Julien (2005) who have proposed division methods and formulations for the calculations of the shear stress values. This paper examines their work and the formulation of Guo and Julien in particular, using detailed Computational Fluid Dynamics simulation results. Numerical results for the various components of shear are presented and the type of division lines computed here compared with the existing propositions, in particular those of Leighly (1932), Keulegan (1938) and the recent findings ofYang and Lim, and Guo and Julien.