Issue 45, 2017

Viscous forces and bulk viscoelasticity near jamming

Abstract

When weakly jammed packings of soft, viscous, non-Brownian spheres are probed mechanically, they respond with a complex admixture of elastic and viscous effects. While many of these effects are understood for specific, approximate models of the particles' interactions, there are a number of proposed force laws in the literature, especially for viscous interactions. We numerically measure the complex shear modulus G* of jammed packings for various viscous force laws that damp relative velocities between pairs of contacting particles or between a particle and the continuous fluid phase. We find a surprising sensitive dependence of G* on the viscous force law: the system may or may not display dynamic critical scaling, and the exponents describing how G* scales with frequency can change. We show that this sensitivity is closely linked to manner in which viscous damping couples to floppy-like, non-affine motion, which is prominent near jamming.

Graphical abstract: Viscous forces and bulk viscoelasticity near jamming

Article information

Article type
Paper
Submitted
11 Aug 2017
Accepted
09 Oct 2017
First published
11 Oct 2017
This article is Open Access
Creative Commons BY license

Soft Matter, 2017,13, 8368-8378

Viscous forces and bulk viscoelasticity near jamming

K. Baumgarten and B. P. Tighe, Soft Matter, 2017, 13, 8368 DOI: 10.1039/C7SM01619K

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