Topological changes in a two-dimensional foam clusterS.J. Cox1, M.F. Vaz2 and D. Weaire1
1 Physics Department, Trinity College, Dublin 2, Ireland
2 Instituto de Ciência de Materiais e Superfícies and Departamento de Engenharia de Materiais, Instituto Superior Técnico, Av. Rovisco Pais, 1096 Lisboa Codex, Portugal
(Received 18 October 2002 / Received in final form 19 March 2003 / Published online: 21 May 2003)
Experiments on a small cluster of bubbles in a nominally two-dimensional foam show an instability in which a topological change forces one of the bubbles to be ejected to the outside of the cluster at a point where this is not predicted by a two-dimensional model of a foam. This is interpreted in terms of the energy of the initial and ejected states and of the finite liquid content of the experimental system. A description of the distribution of liquid in various experimental set-ups suggests that the exact response may depend critically upon the type of system used. This is demonstrated experimentally with reference to small clusters of bubbles undergoing a single topological change.
82.70.Rr - Aerosols and foams.
46.32.+x - Static buckling and instability.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2003