Bubbles in sheared two-dimensional foams
  Oscillatory shear on two-dimensional monodisperse liquid foams was performed. We show that the effect of the oscillatory shear is to cause the migration of bubbles which size is greater than that of a typical bubble of the foam. These so-called flaws move towards the periphery of the foam in a non random motion, thus realizing size segregation in a system which is by construction gravity insensitive. We also show that elongated cavities in the foam could be relaxed towards a more isotropic form with oscillatory shear, and we discuss the pertinent parameters of this relaxation. 
C. Quilliet, M. A. P. Idiart, B. Dollet, L. Berthier, A. Yekini