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Intriguing viscosity effects in confined suspensions: a numerical study

Davit, Yohan and Peyla, Philippe Intriguing viscosity effects in confined suspensions: a numerical study. (2008) Europhysics Letters, 83 (6). 1-6. ISSN 0295-5075

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Official URL: http://dx.doi.org/10.1209/0295-5075/83/64001

Abstract

The effective viscosity of dilute and semi-dilute suspensions in a shear flow in a microfluidic configuration is studied numerically. The suspension is composed of monodisperse and non-Brownian hard spherical buoyant particles confined between two walls in a shear flow. An abrupt change of the viscosity behaviour occurs with strong confinements: when the wall-to-wall distance is below five times the radius of the particles, we obtain a change of the sign of the contribution of the hydrodynamic interactions to the effective viscosity. This effect is the macroscopic counterpart of the peculiar micro-hydrodynamics of confined suspensions due to the influence of walls. In addition, for higher concentrations (above 25%), we find that the viscosity meets a minimum when the inter-wall distance is around five times the sphere radius. This phenomenon is reminiscent of the Fahraeus-Lindqvist effect for blood confined in small capillaries. However, we show that for sheared confined semi-dilute suspensions, the physical origin of this minimum is not due to a migration effect but to the change of hydrodynamic interactions.

Item Type:Article
Additional Information:Thanks to IOP editor. The original PDF can be found at Europhysics Letters website: http://iopscience.iop.org/0295-5075/83/6/64001/
Audience (journal):International peer-reviewed journal
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Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Other partners > Université Joseph Fourier Grenoble 1 - UJF (FRANCE)
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Deposited By: Yohan DAVIT
Deposited On:25 Nov 2013 08:23

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