Characteristics of hyperconcentrated sediment-laden flows

Microscopic and macroscopic characteristics of hyperconcentrated sediment-laden flows are investigated using kinetic theory for differing concentrations of non-cohesive sediment particles. Variations in the microscopic particle velocity distribution function and in derived macroscopic variables such as the particle mean velocity, particle fluctuating velocity, and particle number per unit volume are discussed. Analysis of the microscopic characteristics shows that the peak value of the particle velocity probability density distribution function decreases with increasing vertically averaged volumetric (or mean) particle concentration (C) over bar (upsilon), particularly when (C) over bar (upsilon) exceeds a certain threshold. A case study indicates that the characteristic velocity u(c) is hardly influenced by the particle concentration, but the standard deviation sigma is significantly affected. For given particle concentrations, both u(c) and sigma tend to become larger with increasing relative elevation from the bottom. From the derived macroscopic characteristics, apparent changes can be observed in the profiles of particle mean velocity, particle fluctuating velocity, and particle concentration when (C) over bar (upsilon) is greater than the threshold value.