FOAM MECHANICS AT THE BUBBLE SCALE

By focusing on entire bubbles rather than films or vertices, a simple model is proposed for the deformation and flow of foam in which dimens ionality, polydispersity, and liquid content can easily be varied. Sim ulation results are presented for the linear elastic properties as a f unction of bubble volume fraction, showing a melting transition where the static shear modulus vanishes and the relaxation time scale peaks. Results are also presented for shear stress versus strain rate, showi ng intermittent flow via avalanchelike topological rearrangements and Bingham-plastic behavior.