Séminaire régulier IUSTI – 23 mars 2018 – 11h salle 250

Dynamic of a topological rearrangement in a bubble assembly

Anne-Laure Biance – ILM, Lyon

Liquid foams consist of an assembly of soap bubbles in a liquid matrix. They are extensively used because they are cheap, and light materials with interesting properties for thermal, light and acoustic insulations. However, they are out of equilibrium systems, which in the end always collapse. In a previous work [1], we have shown that dynamical events within the material can trigger the collapse of a foam. In this talk, we will consider a model single dynamical event, called a topological rearrangement of type 1 (a T1), consisting of the switching of neighboring bubbles. In particular, by performing experiments [3] and level-set simulations [4], the role of surface active molecules, necessary for the preparation of liquid foams, is elucidated in this process. [1] A. L. Biance, A. Delbos, and O. Pitois. How topological rearrangements
and liquid fraction control liquid foam stability. Phys. Rev. Lett., 106 :068301, Feb 2011. [2] P. Petit, J. Seiwert, I. Cantat, A. L. Biance. On the generation of a soap film during a topological rearrangement. Journal of Fluid mechanics, 763, p. 286-301 (2015). [3] Titta, A., Le Merrer, M., Detcheverry, F., Spelt, P., & Biance, A. (2018). Level-set simulations of a 2D topological rearrangement in a bubble assembly: Effects of surfactant properties. Journal of Fluid Mechanics, 838, 222-247. Collaborators: Pauline Petit, Andrea Titta, Marie Le Merrer, Peter Spelt, François Detcheverry.