J. Phys. I France
Volume 4, Numéro 8, August 1994
Page(s) 1121 - 1132
DOI: 10.1051/jp1:1994242
J. Phys. I France 4 (1994) 1121-1132

A model of binary assemblies of dises and its application to segregation study

J. P. Troadec1, A. Gervois2, C. Annie1 and J. Lemaître1

1  Groupe Matière Condensée et Matériaux, Université de Rennes 1, 35042 Rennes Cedex, France
2  Service de Physique Théorique, Direction des Sciences de la Matière CE Saclay, 91191 Gif-sur-Yvette Cedex, France

(Received 25 February 1994, accepied in final form 3 May 1994)

We propose a theoretical model of random binary assemblies of discs which is the extension at any packing fraction of a model previously described by Dodds for dense packings. In dilute assemblies, the notion of contact between the grains must be replaced by that of neighbourhood of the grains. We define the neighbours of a disc through the radical tesselation. The model is tested on packings built grain after grain, obtained from numerical simulations. Its results are then compared with experimental results obtained on assemblies built on an air table this shows that the possibility of rearrangement in those assemblies leads to segregation at a local scale.

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