Accumulating Particles at the Boundaries of a Laminar Flow
arXiv:cond-mat/0608019 · doi:10.1016/j.physa.2007.06.030
Abstract
The accumulation of small particles is analyzed in stationary flows through channels of variable width at small Reynolds number. The combined influence of pressure, viscous drag and thermal fluctuations is described by means of a Fokker-Planck equation for the particle density. It is shown that in the limit of vanishing particle size a uniform particle distribution is always approached in the long time limit. For extended spherical particles, conditions are specified that lead to inhomogeneous densities and consequently to particle accumulation and depletion. Hereby the boundary conditions for the particle density play a decisive role: The centers of spherical particles must keep the minimal distance of their radius from the fluid boundaries. The normal components of the forces acting on the sphere then may assume finite values which are diffusively transported into the bulk of the fluid.
arXiv commentfinal version, accepted by Physica A
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- Hydrodynamically enforced entropic trapping of Brownian particles
- How entropy and hydrodynamics cooperate in rectifying particle transport
- A numerical test of stress correlations in fluctuating hydrodynamics
- Giant enhancement of hydrodynamically enforced entropic trapping in thin channels
- Hydrodynamic drift ratchet scalability