Nonlinear Phenomena in Complex Systems, 2007, Vol.10, No.2, pp.116-126

NONLINEAR PHENOMENA IN COMPLEX SYSTEMS
An Interdisciplinary Journal

2007, Vol.10, No.2, pp.116-126

Ultraslow Coarsening in Compartmentalized Granular Gases.
K. van der Weele, D. van der Meer, and D. Lohse

This paper summarizes and extends our earlier results on coarsening in agitated granular matter [D. van der Meer, K. van der Weele, and D. Lohse, JSTAT 1, P04004 (2004)]: Millimeter-sized beads are vertically vibrated in an array of K connected compartments, forming a so-called granular gas. For strong shaking the beads spread evenly over the compartments, but if the shaking strength is lowered beneath a critical level this uniform distribution gives way to a clustered state, consisting of a few well-filled compartments and many diluted ones. In the course of time, this state coarsens: The smaller clusters are eaten by the larger ones, until finally only one big cluster remains. This coarsening process is exceptionally slow, with the mass of the surviving cluster growing as (log t)^1/2. The experimental observations are quantitatively explained by a dynamical flux model.
Key words: granular matter, clustering, coarsening, self-similarity analysis

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