Experimental Study of Reservoir Turbidity Current

Abstract

A series of experiments were conducted in a flume to study the hydraulic characteristics of the turbidity current in a reservoir. Kaolin was used as the suspended material. The plunge points were found to be unstable initially. As the experiment went on, it moved downstream from the incipient plunge location and finally reached a stable location. The densimetric Froude number of the incipient and the stable plunge points are approximately equal to 1.0 and 0.6, respectively. It is found that the length of the plunge region is 15 times the water depth at the stable plunge point. The volumetric flow rates in the plunge region increase 17% during the plunging process. About 70% of the water discharge and 80% of the sediment discharge are confined to the denser layer, a layer close to the channel bed with approximately constant concentration. The thickness of the turbidity current increases while the layer-averaged velocity and concentration decrease in the longitudinal direction; the layer-averaged velocity has the smallest variation rates. Equations for the dimensionless velocity and concentration profiles are obtained.