Three-dimensional model for particle-size segregation by shaking

Abstract

A three-dimensional model for particle-size segregation by shaking has been developed and used to study the upward motion of a large sphere in a random packing of smaller spheres. In this model segregation occurs only for values of the diameter ratio (Φ) above a critical value ${\mathrm{\Phi }}_{\mathit{c}}$≃2.8. The ratio of the upward velocity of the large particles to their diameter is greatest for values of Φ just larger than ${\mathrm{\Phi }}_{\mathit{c}}$. The simulation results can be understood in terms of a simple theoretical model that becomes exact in the limit Φ→∞.