Axial dispersion via shear-enhanced diffusion in colloidal suspensions

Type
Article

Authors
Griffiths, I. M.
Stone, H. A.

KAUST Grant Number
KUK-C1-013-04

Online Publication Date
2012-03-05

Print Publication Date
2012-03-01

Date
2012-03-05

Abstract
The familiar example of Taylor dispersion of molecular solutes is extended to describe colloidal suspensions, where the fluctuations that contribute to dispersion arise from hydrodynamic interactions. The generic scheme is illustrated for a suspension of particles in a pressure-driven pipe flow, with a concentration-dependent diffusivity that captures both the shear-induced and Brownian contributions. The effect of the cross-stream migration via shear-induced diffusion is shown to dramatically reduce the axial dispersion predicted by classical Taylor dispersion for a molecular solute. Analytic and numerical solutions are presented that illustrate the effect of the concentration dependence of this nonlinear hydrodynamic mechanism. Copyright © EPLA, 2012.

Citation
Griffiths, I. M., & Stone, H. A. (2012). Axial dispersion via shear-enhanced diffusion in colloidal suspensions. EPL (Europhysics Letters), 97(5), 58005. doi:10.1209/0295-5075/97/58005

Acknowledgements
This publication is based on work partially supported by Award No. KUK-C1-013-04, made by King Abdullah University of Science and Technology (KAUST). We gratefully acknowledge helpful discussions with J. M. ARISTOFF, Y. DAVIT, W. HOLLOWAY, P. D. HOWELL, M. REYSSAT, R. RUSCONI and R. W. STYLE. We thank E. J. HINCH for helpful feedback with the paper, including the argument for the correlation distance, and thank an anonymous referee for emphasizing the distinctions between the various modes of diffusive transport in suspensions.

Publisher
IOP Publishing

Journal
EPL (Europhysics Letters)

DOI
10.1209/0295-5075/97/58005

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