Preliminary analysis on movement of density current with low sediment content simulated by pseudo-chark

Density currents with low sediment concentration are muddy and consist of a large number of fine granular particles. The extremely small settling velocity of the granules leads to adverse water environment, and immense difficulties in water diversion and water treatment in mountainous and plateau areas. This is a cause of concern for society in general, and design departments in particular. In this work, we have used the upper and lower reaches of the Niulan River, a tributary of the Jinsha River, as prototypes, and studied the formation and movement of currents with low sediment concentration and density using a generalized flume test. In addition, we have explored the variations in the characteristics of the head velocity and sediment concentration along the flow path. The results reveal a gradual decrease of the head velocity and sediment concentration along the flow path. For the same amount of discharge, the head velocity of the middle and bottom layers of the current increases with an increase in the sediment concentration. The top layer exhibits a higher head velocity compared to the middle and bottom layers for the same amount of discharge and sediment concentration. The middle layer exhibits the smallest velocity head, while the velocity head of the bottom layer has an intermediate value. These results can serve as a guide for test simulations of physical models of reservoirs.