Oscillatory granular segregation in a long drum mixerZ. S. Khan, W. A. Tokaruk and S. W. Morris
Department of Physics, University of Toronto 60 St. George St., Toronto, Ontario, Canada M5S 1A7
(Received 9 October 2003; accepted in final form 4 February 2004)
Heterogeneous granular mixtures tend to segregate when tumbled in a partially filled, horizontal rotating drum. The dynamical evolution of segregation can, under certain conditions, be oscillatory. Continuum, order parameter-style models of this process posit two coupled fields which oscillate out of phase with one another. Here we examine three candidate fields, the surface concentration, the local streaming angle and the projected concentration of the subsurface core. We find that all these quantities are in phase with one another, in contradiction to a recent order parameter model.
45.70.Mg - Granular flow: mixing, segregation and stratification.
45.70.Qj - Pattern formation.
© EDP Sciences 2004