Flow Resistance And Sediment Transport In Compound Channels

A compound channel comprising the main channel and floodplains exists in natural rivers widely, especially in alluvial streams. It differs from a single channel in adjusting flood, cutting flood peak, transporting sediment etc. When water in the main channel flows in an out-of-bank condition and on to the adjoining floodplain, owing to abrupt change of the shape of cross section and heterogeneous boundary roughness, there are a bank of vertical vortices along the vertical interface between the main channel and its floodplain, which will result in complex variations in flow structure, flow resistance, sediment transport and fluvial processes. The sduty of the complex behavior of flow movement and sediment transport in compound channels is profoundly important for the basic theory of mechanics of sediment transport and river dynamics. The research results benefit to flood control, channel training, floodplain exploitation etc. The thesis will systematacially investigates flow resistance, mechanism of momentum transfer, conveyance capacity in non-vegetated compound channels, flow structure in a compound channels with vegetated floodplains, flow resistance and sediment transport in a self-formed one. The main contents of the thesis are as follows:The thesis analyzes and discusses the effect of cross-sectional shape on Manning's and Darcy-Weisbach resistance coefficients. By analyzing the experimental data from Science and Engineering Research Council Flood Channel Facility (SERC-FCF), the relationships between overall, zonal, local resistance coefficients and a wide range of geometries and different roughness between the main channels and its associated...