Eur. Phys. J. E (2015) 38: 47
https://doi.org/10.1140/epje/i2015-15047-x

Regular Article

Transient dynamics of a 2D granular pile

¹ LMGC, UMR 5508, University Montpellier 2 - CNRS, F-34095, Montpellier cedex 5, France
² IATE, UMR1208 INRA, University Montpellier 2, Cirad - Montpellier Sup Agro, F-34060, Montpellier cedex 1, France
³ Engineering Department, Cambridge University, CB2 1PZ, Cambridge, UK
⁴ MultiScale Material Science for Energy and Environment, UMI 3466 CNRS-MIT, CEE, Massachusetts Institute of Technology, 77 Massachusetts Avenue, 02139, Cambridge, USA

^* e-mail: patrick.mutabaruka@univ-montp2.fr

Received: 20 January 2015
Revised: 9 March 2015
Accepted: 9 April 2015
Published online: 26 May 2015

Abstract

We investigate by means of Contact Dynamics simulations the transient dynamics of a 2D granular pile set into motion by applying shear velocity during a short time interval to all particles. The spreading dynamics is directly controlled by the input energy whereas in recent studies of column collapse the dynamics scales with the initial potential energy of the column. As in column collapse, we observe a power-law dependence of the runout distance with respect to the input energy with nontrivial exponents. This suggests that the power-law behavior is a generic feature of granular dynamics, and the values of the exponents reflect the distribution of kinetic energy inside the material. We observe two regimes with different values of the exponents: the low-energy regime reflects the destabilization of the pile by the impact with a runout time independent of the input energy whereas the high-energy regime is governed by the input energy. We show that the evolution of the pile in the high-energy regime can be described by a characteristic decay time and the available energy after the pile is destabilized.