Hydrodynamic Diffusion of Particles in Microscale

Abstract

Sedimentation of solid particles is an important phenomenon in various engineering processes related to coating, accumulation, separation, filtration and so on. It is well-known that the sedimentation velocity in a stationary fluid is influenced by hydrodynamic interactions between particles and is a function of volumetric concentration of particles. In addition, the hydrodynamic interactions induce complex effects, such as the large-scale fluctuations in the sedimentation velocity, the self-diffusion of particles and the instability at the interface of sedimenting suspension. In this paper, the hydrodynamic diffusion, which is one of the hydrodynamic effects, of particle layer with a finite height is discussed. Researches on the hydrodynamic diffusion are reviewed and our recent numerical studies on the diffusivity of particles in microscale are reported.