Author(s): Xudong Fu; Guangqian Wang; Gordon Huang
Linked Author(s): Xudong Fu, Guangqian Wang
Keywords: Kinetic model; Fokker-Planck operator; BGK model; Simple shear flow; Sediment; Diffusion; Collision; Asymptote
Abstract: Formulating various underlying mechanisms is essential for modeling sediment-transport in turbulent concentrated flows. In this study, a kinetic model allowing for collisional dissipation, correlation between two colliding particles, and certain shear rate was developed. A comparison with experimental data of solid-fluid mixtures in a relatively concentrated simple shear flow shows a good agreement. The varying importance of the phasic stresses with concentration shows that a generalized model like the present one should be applied to flows with C ranging from 0.2 to 0.5; outside this intermediate range of C, previous rapid-granular-flow or low-concentration models may be practical alternatives. The C→0 asymptote occurs at a relatively high shear rate, for which low collisional dissipation of the particle phase in the dilute limit (C→0) can be responsible. No consideration of friction forces among particles lowers the applicability of the present model to extremely concentrated flows.
Year: 2004