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Stationary state volume fluctuations in a granular medium

Matthias Schröter·Daniel I. Goldman·Harry L. Swinney
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Abstract

A statistical description of static granular material requires ergodic sampling of the phase space spanned by the different configurations of the particles. We periodically fluidize a column of glass beads and find that the sequence of volume fractions phi of post-fluidized states is history independent and Gaussian distributed about a stationary state. The standard deviation of phi exhibits, as a function of phi, a minimum corresponding to a maximum in the number of statistically independent regions. Measurements of the fluctuations enable us to determine the compactivity X, a temperature-like state variable introduced in the statistical theory of Edwards and Oakeshott [Physica A {\bf 157}, 1080 (1989)].

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Matthias Schröter, Daniel I. Goldman, Harry L. Swinney. 2005-03-31. Stationary state volume fluctuations in a granular medium. https://doi.org/10.1103/physreve.71.030301

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