Simple model of sediment-laden flows

A theoretical model of sediment-laden flow is applied to dilute openchannel suspensions. It is found that the effect of the sediment is manifested in terms of a reduced depth and coefficient of resistance, and an increased mean velocity of flow. In particular, an expression for the effect of sediment on the wake strength parameter Π of the velocity profile can be derived. The expression predicts results that are in agreement with the measurements of a previous study. Another prediction of the theory concerns the level of turbulence. The ratio of the power consumed by the flow in holding the sediment in suspension to the power supplied to the flow by the work of the downstream pull of gravity on the sediment is used to form a dimensionless ratio. If this ratio is less than unity, i.e., sufficiently fine sediment, the turbulence is intensified; otherwise, it is damped.