Density segregation in vibrated granular beds with bumpy surfaces

Abstract

Segregation of granular materials by virtue of density or size is a commonly encountered phenomenon in nature. Despite its widespread interest among many researchers in recent years, a complete and unified understanding of granular segregation remains elusive to date. Using molecular dynamics simulations, we report a novel technique of inducing density segregation in a binary mixture of granular materials subjected to vibrations by the use of a bumpy vibrating base. Density segregation in the vertical directions may be induced by oscillating the bumpy base composed of discrete solid particles vertically or horizontally. In both cases, lighter particles tended to rise to the top of the granular bed and form a layer above the heavier particles. We suggest that differences in granular temperature profiles arising from the two different modes of vibrations may play an important role in determining the extent of density segregation occurring in binary granular mixtures. © 2010 American Institute of Chemical Engineers AIChE J, 2010

Influence of initial conditions on granular dynamics near the jamming transition

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Density-Driven Segregation in Binary and Ternary Granular Systems

“…The 'ordinary' or thermodynamic temperature can safely be assumed negligible when considering the behaviour of granular systems due to the large sizes, and hence high energies, of the particles involved (Jaeger et al, 1996). The granular temperature is an important quantity to consider, as it affects many aspects of a granular system's behaviour, including segregative processes (Lim, 2010). preliminary tests in which ternary beds of height H = 33.8 and H = 8.4 were driven with a constant acceleration Γ = 5 over a period of 3600 s. By utilising both the weakest driving and most polydisperse systems used in experiment, we can safely assume that these 'test runs' will provide an upper limit for the time required to reach a steady state (Windows-Yule et al, 2014).…”

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