Myfanwy Evans’ animation of diffusive coarsening of a random liquid foam
Here’s Myfanwy Evans‘ animation of her Surface Evolver study of diffusive coarsening. Diffusive coarsening is the process by which the cells of a random liquid foam grow or shrink as a consequence of slow gas diffusion through the cell membranes, driven by pressure differences between adjacent cells. The Surface Evolver software has been used to study this phenomenom, using a quasistatic approach that essentially incorporates topological changes when cells change neighborhood. While the problem in 2D is purely topological, due to the Von Neumann law, the dependence of growth rates in 3D foams is dependent on both cell topology and cell geometry.
While we never quite got around to quantitatively analysing these simulations to publication standard, Myfanwy did some very nice work -simulation and experiment- on a simpler single-cell diffusive growth model (in collaboration with Johannes Zirkelbach and Andrew Kraynik). This study considered three of the Platonic solids (tetrahedron, cube and dodecahedron) and converted them into ‘Plateaunic cells’, that is, soap film bubbles suspended from deformable wire frames. Inspired by Andrew Kraynik’s and Sascha Hilgenfeldt‘s earlier work on their undeformed counterparts (called isotropic Plateau polyhedra), Myfanwy was able to clearly demonstrate the strong geometric (rather than topological) component of the diffusive growth law in three-dimensional systems. This work was published in the article below:
M.E. Evans, J. Zirkelbach, G.E. Schröder-Turk, A.M. Kraynik, and K. Mecke, Deformation of Platonic foam cells: Effect on growth rate , Phys. Rev. E 85 , 061401 (2012)
More of Myf’s, Andy’s and my work on foams has been published here:
- M.E. Evans, G.E. Schröder-Turk, A.M. Kraynik, “A geometric exploration of stress in deformed liquid foams“, J. Phys.: Condens. Matter 29, 124004 (2017)
- M.E. Evans, A.M. Kraynik, D.A. Reinelt, K. Mecke and G.E. Schröder-Turk, “Networklike Propagation of Cell-Level Stress in Sheared Random Foams“, Phys. Rev. Lett. 111, 138301 (2013)
- G.E. Schröder-Turk, W. Mickel, S.C. Kapfer, M.A. Klatt, F.M. Schaller, M.J.F. Hoffmann, N. Kleppmann, P. Armstrong, A. Inayat, D. Hug, M. Reichelsdorfer, W. Peukert, W. Schwieger and K. Mecke, “Minkowski Tensor Shape Analysis of Cellular, Granular and Porous Structures”, Advanced Materials 23, 2535-2553 (2011)