Issue |
EPL
Volume 116, Number 1, October 2016
|
|
---|---|---|
Article Number | 14001 | |
Number of page(s) | 7 | |
Section | Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics | |
DOI | https://doi.org/10.1209/0295-5075/116/14001 | |
Published online | 16 November 2016 |
Active dry granular flows: Rheology and rigidity transitions
1 Physique et Mécanique des Milieux Hétérogènes, PMMH UMR 7636 ESPCI - CNRS - Univ. Paris-Diderot - Univ. P.M. Curie - 10 rue Vauquelin, 75005 Paris, France
2 Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile Av. Blanco Encalada 2008, Santiago, Chile
Received: 9 July 2016
Accepted: 25 October 2016
The constitutive relations of a dense granular flow composed of self-propelling frictional hard particles are investigated by means of DEM numerical simulations. We show that the rheology, which relates the dynamical friction μ and the volume fraction ϕ to the inertial number I, depends on a dimensionless number , which compares the active force to the confining pressure. Two liquid/solid transitions —in the Maxwell rigidity sense— are observed. As soon as the activity is turned on, the packing becomes an “active solid” with a mean number of particle contacts larger than the isostatic value. The quasi-static values of μ and ϕ decrease with
. At a finite value of the activity
, corresponding to the isostatic condition, a second “active rigidity transition” is observed beyond which the quasi-static values of the friction vanishes and the rheology becomes Newtonian. For
, we provide evidence for a highly intermittent dynamics of this “active fluid”.
PACS: 47.57.Gc – Granular flow / 83.80.Fg – Granular solids / 05.65.+b – Self-organized systems
© EPLA, 2016
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.