Jamming and geometry of two-dimensional foams

¹ Kamerlingh Onnes Laboratorium, Universiteit Leiden - P.O. Box 9504, 2300 RA Leiden, The Netherlands, EU
² School of Physics, The University of Edinburgh, James Clerk Maxwell Building, The Kings Buildings Mayfield Road, Edinburgh EH9 3JZ, UK, EU

^a g.katgert@ed.ac.uk

Received: 29 July 2010
Accepted: 13 October 2010

Abstract

We experimentally probe the vicinity of the jamming point J, located at a density φ corresponding to random close packing (φ_rcp=0.842), in two dimensional, bidisperse packings of foam bubbles. We vary the density of the foam layer and extract geometrical measures by image analysis. We confirm the predicted scaling of the average contact number Z with φ and compare the distribution of local contact numbers to a simple model. We further establish that the distribution of areas p(A) strongly depends on φ. Finally, we find that the distribution of contact forces p(f) systematically varies with density.