Water (Aug 2022)

Estimation of Boundary Shear Stress Distribution in a Trapezoidal Cross-Section Channel with Composite Roughness

  • You Luo,
  • Senlin Zhu,
  • Fan Yang,
  • Wenxiang Gao,
  • Caiming Yan,
  • Rencong Yan

Journal volume & issue
Vol. 14, no. 16
p. 2530


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The estimation of boundary shear stress distribution in a channel is a challenge in some hydraulic or environment investigations. A new partition model of a trapezoidal cross-section in a prismatic channel with composite roughness has been introduced based on a concept of a standardized cross-section using the “zero-shear stress” division lines. Based on this new model, an “equal local-region velocity” assumption, which can be regarded as an improvement of Einstein’s (1942) “equal velocity” assumption, has been proposed that is based on a discussion on the mechanism of energy transfer and velocity distribution at two sides of a dividing line. This assumption along with some empirical treatments have been employed to establish a new method to estimate the boundary shear stress of a side-wall or bed. Comparisons show that the proposed method can be applied to composite roughness cases and provides better prediction performance compared to other methods.