Abstract

Compared with ordinary sediment-laden flows, hyperconcentrated sediment-laden flows have many distinct properties, which play very important roles in the processes of flood routing and channel adjustment. These properties include settling velocity, flow pattern, velocity distribution, sediment transport capacity, movable bed resistance, and so on. Hyperconcentrated sediment-laden flows usually cause serious deposition in the Lower Yellow River, and therefore, study on hyperconcentrated flows is helpful to both improvement of sediment transport theory and application in practical Engineering. Among previous models, the influence of sediment concentration on the process of flood routing was often ignored in the flow governing equations, and however, this omitting will lead to a certain error. In this paper, a one-dimensional (1D) model for simulating hyperconcentrated sediment-laden flows is proposed, in which the governing equations for flow consist of continuity and momentum equations for turbid flow. In addition, the influence of sediment concentration on sediment transport capacity is accounted for. The model is calibrated by the hyperconcentrated flood occurred in 1977, then another flood occurred in 1982 is chosen to verify the model. Simulated resulted showed that the sediment concentration plays an important role in flood routing, and it is necessary to adopt the turbid flow governing equations as the concentration of sediment-laden flow is relatively higher.

Keywords: Lower Yellow River, hyperconcentrated sediment-laden flow, turbid flow continuity equation, turbid flow momentum equation, flood routing, channel adjustment