Title
Segregation-driven Patterns and Controlled Convection in Vertically Vibrated Binary Granular Mixtures
Speaker
Meheboob Alam (Jawaharlal Nehru Centre for Advanced Scientific Research)
Abstract
Unlike molecular fluids, segregation or demixing occurs
spontaneously in driven
granular mixtures of different size and/or density particles which can be a
nuisance/blessing in processing industries dealing with granular materials.
Understanding segregation-driven patterns and finding ways to control them
remains a key challenge in granular physics research. I will discuss our recent
experimental results on novel patterns displaying the coexistence of
sub-harmonic
and synchronous states and that of gas- and liquid-like states in
experiments on
vertically vibrated binary granular mixtures in a
quasi-two-dimensional Hele-Shaw cell.
The segregation of heavier and lighter particles along the horizontal direction
is shown to be the progenitor of such phase-coexisting patterns.
The phase diagram of all patterns has been identified, and a simple recipe to
control ``buoyancy-driven'' granular convection is demonstrated. Theoretical
challenges to predict such phase-coexisting patterns will be discussed.
In the second part of this talk, I'll briefly outline an order-parameter theory
for nonlinear granular convection in vibrated mono-disperse system.
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