Europhys. Lett.
Volume 75, Number 4, August 2006
Page(s) 576 - 582
Section Electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics
Published online 14 July 2006
Europhys. Lett., 75 (4), pp. 576-582 (2006)
DOI: 10.1209/epl/i2006-10154-1

Radial segregation driven by axial convection

A. C. Santomaso, L. Petenò and P. Canu

DIPIC, Università di Padova - via Marzolo 9, 35131 Padova, Italy

received 2 March 2006; accepted in final form 29 June 2006
published online 14 July 2006

We experimentally study the mixing of binary granular systems in a horizontal rotating cylinder. When materials have the same size and differ by dynamic angle of repose only, we observe an axial transport of matter that generates transient radial segregation. The system then evolves towards homogeneity. If materials differ by density also radial segregation becomes steady. A mechanism is suggested where radial segregation is promoted by axial differences of dynamic angle of repose. This differs from the free surface segregation suggested so far to explain radial segregation.

45.70.Mg - Granular flow: mixing, segregation and stratification.
45.70.Qj - Pattern formation.

© EDP Sciences 2006