Dispersion of Silt Particles in Open Channel Flow

The dispersion process for sediment particles in a two-dimensional turbulent shear flow is formulated in two differential equations, one for particles suspended in the flow and the other for those deposited on the bed. Exchange of particles between the bed and the flow is permitted. Using the Aris moment transformations, the equations are converted to a more tractable system of equations which are solved by numerical methods with the aid of a digital computer, for the zero'th, first, second and third moments of the longitudinal concentration distributions. Various combinations of boundary and other input conditions are imposed and their effects on the dispersion process are demonstrated. The results of the numerical solutions together with the results of earlier dispersion experiments with silt particles and fluorescent dyes show that the tendency of the silt particles toward deposition and temporary storage on the bed can profoundly affect the longitudinal dispersion process.