Author(s): Xingnian Liu; Zhixiang Zhang; Kejun Yang; Shuyou Cao
Linked Author(s): Xingnian Liu, Kejun Yang
Keywords: Compound channels; Methods for predicting component resistance; SERC-FCF; Comparison and analysis; Mean boundary shear stress
Abstract: Resistance plays an important role in determining conveyance capacity and sediment transport in compound channels. In the paper, all kinds of representative methods for predicting component resistances were systematically summarized, i. e. cross-sectional division method (CSDM), momentum transfer method (MTM), Liu and Dong’s method (LDM), channel coherence method (COHM), Shiono and Knight’s method (SKM). On the basis of experimental data from Science and Engineering Research Council Flood Channel Facility (SERC-FCF), the mean boundary shear stresses of each subzone were computed for different series. The computed results indicate that SKM and inclined division method type 1 (IDMT1) obtain very high precision, and the other methods can not fit to assess the component resistances. By comparing the two cases of considering and ignoring the effect of secondary flow by SKM, it is found that the secondary flow strongly affects the distribution of boundary shear stress. If ignoring it, we can not correctly assess the component resistances. Furthermore, it is pointed out that the reasons why the other methods mentioned above are not fit for compound channels, lie in the facts that LDM, MTM and COHM don’t consider the influence of the secondary flow on the distribution of the bed shear stress. Therefore, in determining the component resistances in a compound channel, SKM is a good method worthy of recommending.
Year: 2005