Europhys. Lett.
Volume 66, Number 2, April 2004
Page(s) 205 - 211
Section Electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics
Published online 01 April 2004
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. Losert1

1  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)

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.

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