Europhys. Lett., 66 (2) , pp. 205-211 (2004)
DOI: 10.1209/epl/i2003-10207-y

Band-in-band segregation of multidisperse granular mixtures

M. Newey¹, J. Ozik¹, S. M. van der Meer², E. Ott¹ and W. Losert<sup>1

1</sup>  Institute for Research in Electronics and Applied Physics, University of Maryland College Park, MD 20742-3511, USA
²  Department of Applied Physics and J.M. Burgers Centre for Fluid Dynamics University of Twente - P.O. Box 217, 7500 AE Enschede, The Netherlands

(Received 30 September 2003; accepted in final form 16 February 2004)

Abstract
Radial and axial segregation is investigated experimentally in polydisperse mixtures of granular materials rotated in a long, partly filled, horizontal cylinder. Radial segregation by size is observed in all polydisperse mixtures. Axial segregation, with smaller-size particles forming bands within bands of larger-size particles, is observed for mixtures of 3 sizes. In addition, bands in ternary mixtures oscillate axially under some conditions. It is observed that the surface flow speeds depend on the particle size, both in the mixed and segregated case. A simple microscopic model based solely on different frictional properties of three particles yields qualitatively similar results.

PACS
45.70.Mg - Granular flow: mixing, segregation and stratification.
64.75.+g - Solubility, segregation, and mixing; phase separation.
05.65.+b - Self-organized systems.

© EDP Sciences 2004

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