Fast decay of the velocity autocorrelation function in dense shear flow of inelastic hard spheres

Orpe, Ashish V and Kumaran, V and Reddy, Anki K and Kudrolli, Arshad (2008) Fast decay of the velocity autocorrelation function in dense shear flow of inelastic hard spheres. In: Europhysics Letters, 84 (6). 64003-1-64003-6.

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Abstract

We find in complementary experiments and event-driven simulations of sheared inelastic hard spheres that the velocity autocorrelation function psi(t) decays much faster than t(-3/2) obtained for a fluid of elastic spheres at equilibrium. Particle displacements are measured in experiments inside a gravity-driven flow sheared by a rough wall. The average packing fraction obtained in the experiments is 0.59, and the packing fraction in the simulations is varied between 0.5 and 0.59. The motion is observed to be diffusive over long times except in experiments where there is layering of particles parallel to boundaries, and diffusion is inhibited between layers. Regardless, a rapid decay of psi(t) is observed, indicating that this is a feature of the sheared dissipative fluid, and is independent of the details of the relative particle arrangements. An important implication of our study is that the non-analytic contribution to the shear stress may not be present in a sheared inelastic fluid, leading to a wider range of applicability of kinetic theory approaches to dense granular matter.

Item Type:	Journal Article
Publication:	Europhysics Letters
Publisher:	EDP Sciences
Additional Information:	Copyright of this article belongs to EDP Sciences.
Department/Centre:	Division of Mechanical Sciences > Chemical Engineering
Date Deposited:	01 May 2009 06:52
Last Modified:	19 Sep 2010 05:28
URI:	http://eprints.iisc.ac.in/id/eprint/19489

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