Spatial distribution functions of random packed granular spheres obtained by direct particle imaging

Abstract

We measure the two-point density correlations and Voronoi cell distributions of cyclically sheared granular spheres obtained with a fluorescence technique and compare them with random packing of frictionless spheres. We find that the radial distribution function $g(r)$ is captured by the Percus-Yevick equation for initial volume fraction $\varphi =0.59$. However, small but systematic deviations are observed because of the splitting of the second peak as $\varphi$ is increased towards random close packing. The distribution of the Voronoi free volumes deviates from postulated $\Gamma$ distributions, and the orientational order metric $Q_6$ shows disorder compared to numerical results reported for frictionless spheres. Overall, these measures show significant similarity of random packing of granular and frictionless spheres, but some systematic differences as well.

4 pages, 4 figures

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Cited by in corpus (7)

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