Eur. Phys. J. Special Topics 204, 19-25 (2012)
https://doi.org/10.1140/epjst/e2012-01549-7

Regular Article

Stick slip displacement of confined granular mixtures: Bubble expansion

¹ Department of Physics, Norwegian University of Science and Technology, Hoegskoleringen 5, 7491 Trondheim, Norway
² School of Chemical and Biomolecular Engineering, University of Sydney, Sydney, New South Wales 2006, Australia
³ Department of Physics, University of Oslo, Sem Sælands vei 24, PO Box 1048 Blindern, 0316 Oslo, Norway

^a e-mail: bjornar.sandnes@ntnu.no

Received: 23 December 2011
Revised: 22 February 2012
Published online: 17 April 2012

Abstract

When a compressible gas displaces a granular mixture in a quasi 2D space, friction causes stick slip motion. A localized slip event at the interface allows expansion of the compressed gas and a sudden forward motion of the front. The reservoir volume of gas determines the available elasticity in the system, and thereby the size of the expansion. Large expansions take the shape of bubbles, and in this paper we study the accumulation of granular material around the inflating gas bubble, and the rheological response of the system during this short expansion phase.