Shear-induced changes in two-dimensional foam

The effects of shear strain on a two-dimensional foam, comprising a monolayer of bubbles bridging from a soap solution to a cover glass, have been studied. For initially disordered foam, μ₂, the second central moment of the distribution of bubble coordination numbers, fell under strain, indicating ordering. The reduction in μ₂ is proportional to its initial value. Further, the accompanying bubble-level changes occur in clusters, some of which are large. Comparisons are drawn with recent studies.