Studying localized bubble rearrangements in 2D liquid foams using a hybrid lattice gas model

We report numerical studies of structural changes in 2D liquid foams using a hybrid lattice gas model. Our simulations of dry foams show that the length of a new edge forming in the course of such a T1 process grows with the square root of time, followed by an exponential relaxation of the foam to equilibrium. In wet foams, which feature Plateau borders with at least four sides, we trigger bubble rearrangements (defined by the formation or loss of contacts between bubbles) by pushing a small rigid disk through foam. We find that rearrangements mainly occur within about five bubble radii of the disk. The average number of bubble rearrangements per bubble is a function of liquid fraction, with a maximum at ϕ ≈ 0.072, approximately half-way between the dry and wet limits.