Prediction of Sediment Profiles in Open Channel Flow by Turbulent Diffusion Theory

Abstract

Using turbulent diffusion theory, a non‐steady‐state model of sediment transportation is developed in the form of a partial differential equation relating the change of sediment concentration with time to the change of concentration in space. The required input to the model is the root‐mean‐square fluid velocity, the time scale of turbulence, and the mean particle fall velocity. Preliminary experimental investigations are reported using turbulence measurements made over a smooth channel. When smooth channel turbulent intensities were used, predicted sediment concentrations were low when compared with actual measurements. When turbulent intensities were used from an artificially roughened channel, the predicted concentrations were; of the same order as the measured concentrations. Since data were not available for turbulent intensities in alluvial channels, no conclusion could be made about the validity of the model.