The evolution of defects in a two-dimensional wet foam

This paper investigates the evolution of defects in two-dimensional (2D) wet foams by using the dynamic bubble simulation approach. Two defect types are considered: a single large bubble, and a cluster of small bubbles inserted in an otherwise monodisperse hexagonal lattice. In the case of a single large defect bubble, the disorder of the cluster associated with the defect is seen to increase and peak before returning to a state having a degree of order different from that of the disordered foam scaling state. This long-timescale behaviour agrees with recent 2D wet-foam experiments yet disagrees with the majority of existing simulations on dry foam. The inclusion of a finite liquid content in the present simulations is identified as a possible reason for the improved predictions. In the case of a defect of small bubbles, coarsening trends observed in experiments are reproduced. Unlike the case for a single large bubble defect, no peak was observed in the disorder of the bubble cluster