Wednesday, July 4, 2012

1207.0146 (A. E. Roth et al.)

Bubble statistics and coarsening dynamics for quasi-two dimensional
foams with increasing liquid content
   [PDF]

A. E. Roth, C. D. Jones, D. J. Durian
We report on experiments in which foams are created and allowed to coarsen in a custom cell that permits the liquid content of the foam to be chosen and held constant for an extended period of time. With increasing liquid content the average coarsening rate decreases, and we are able to achieve a factor of four reduction from the dry limit. We observe that all samples evolve into a statistically self-similar scaling state, where distribution shapes are independent of time and are, furthermore, not affected by liquid content. In addition to usual quantities such as side number and area distributions, neighbor correlations, and size-topology correlations, we also report on bubble shape statistics and the area-weighted side number distribution. The latter is important for the rate of change of average bubble area. At the individual bubble level, we observe that von Neumann's law is systematically violated for small bubbles in a way that depends on liquid content. This effect is explained by a simplistic `border-blocking' model, where the von Neumann argument is modified by assuming that gas diffusion is totally blocked by Plateau borders whose size inflates with wetness.
View original: http://arxiv.org/abs/1207.0146

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