Oscillatory granular segregation in a long drum mixer
Oscillatory granular segregation in a long drum mixer
Europhysics Letters, 66, 212, (2004).
Zeina S. Khan, Wayne A. Tokaruk and Stephen W. Morris
Department of Physics,
University of Toronto, 60 St. George St., Toronto, Ontario, Canada M5S 1A7.
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.
