Jamming and geometry of two-dimensional foams

We experimentally probe the vicinity of the jamming point J, located at a density phi corresponding to random close packing (phi(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 phi 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 phi. Finally, we find that the distribution of contact forces p(f) systematically varies with density. Copyright (C) EPLA, 2010