Abstract The objective of this study was to characterize the influence of sediment discharge on the morphology of movable bed, asymmetric, open-channel confluences. For this purpose, fifteen experiments were performed on rough turbulent flows through an experimental confluence, by running a single combination of confluent discharges and using a single bed material, with three different sediment loads in the main channel combined with five different sediment loads in the tributary channel. The experiments were run until equilibrium was reached. Physical interpretations of the influence of the sediment amount fed into the system on the most important variables and parameters of the confluent flows and confluence morphology were provided. Morphological variables considered included the height of the tributary mouth bar, the depth of the scour hole located in the vicinity of the tributary mouth, the deviation angle of the tributary flow and the dimensions of the bank-attached bar. The hydrodynamic parameters of the confluent flows studied included the unit momentum flux, the unit stream power or the ratio of confluent unit momentum fluxes. The crucial importance of the sediment load entering the system was highlighted since it was documented that i) both channels upstream of the confluence adapted their respective bed slope, flow depth and average flow velocity to respond to the independent sand amounts entering the system; ii) the characteristic dimensions and shape of the most important confluence features changed consistently with the imposed changes on the sediment discharge ratio and concentration; iii) for a given water discharge ratio, the unit momentum flux ratio depended on the sediment amounts flowing through the confluence instead of being an independent parameter.

中文翻译：

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排沙对动床明渠合流平衡床形态的影响

摘要 本研究的目的是表征泥沙排放对可移动床、非对称明渠合流形态的影响。为此，对通过实验合流的粗糙湍流进行了 15 次实验，通过运行合流排放的单一组合并使用单一床材料，在主河道中使用三种不同的沉积物负载，在支流中使用五种不同的沉积物负载渠道。进行实验直到达到平衡。提供了进入系统的沉积物量对合流流和合流形态的最重要变量和参数的影响的物理解释。考虑的形态变量包括支流口条的高度，支流口附近冲刷孔的深度、支流偏流角和附岸杆尺寸。所研究的汇合流的水动力参数包括单位动量通量、单位流功率或汇合单位动量通量之比。进入系统的泥沙负荷的关键重要性得到了强调，因为有记录表明：i) 汇合上游的两个通道都调整了各自的床坡、水流深度和平均流速，以响应进入系统的独立沙量；ii) 最重要的汇流特征的特征尺寸和形状随着排沙比和浓度的强加变化而发生一致变化；iii) 对于给定的排水比率，