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Propagating front in an excited granular layer

W. Losert·D. G. W. Cooper·J. P. Gollub
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Abstract

A partial monolayer of ~ 20000 uniform spherical steel beads, vibrated vertically on a flat plate, shows remarkable ordering transitions and cooperative behavior just below 1g maximum acceleration. We study the stability of a quiescent disordered or ``amorphous'' state formed when the acceleration is switched off in the excited ``gaseous'' state. The transition from the amorphous state back to the gaseous state upon increasing the plate's acceleration is generally subcritical: An external perturbation applied to one bead initiates a propagating front that produces a rapid transition. We measure the front velocity as a function of the applied acceleration. This phenomenon is explained by a model based on a single vibrated particle with multiple attractors that is perturbed by collisions. A simulation shows that a sufficiently high rate of interparticle collisions can prevent trapping in the attractor corresponding to the nonmoving ground state.

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W. Losert, D. G. W. Cooper, J. P. Gollub. 1999-04-05. Propagating front in an excited granular layer. https://doi.org/10.1103/physreve.59.5855

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