Phases of granular segregation in a binary mixture

TL;DR

This study experimentally explores granular segregation in a binary mixture on a vibrating tray, identifying three phases and how they transition based on system parameters like filling fraction and acceleration.

Contribution

It maps out the phases of granular segregation and their transitions, introducing measures based on Voronoi tessellation to analyze the phenomena.

Findings

Identifies three segregation phases: gas, liquid, crystal.

Segregation can be suppressed by adjusting filling fraction and acceleration.

Transitions between phases depend on critical values of control parameters.

Abstract

We present results from an extensive experimental investigation into granular segregation of a shallow binary mixture in which particles are driven by frictional interactions with the surface of a vibrating horizontal tray. Three distinct phases of the mixture are established viz; binary gas (unsegregated), segregation liquid and segregation crystal. Their ranges of existence are mapped out as a function of the system's primary control parameters using a number of measures based on Voronoi tessellation. We study the associated transitions and show that segregation can be suppressed is the total filling fraction of the granular layer, $C$, is decreased below a critical value, $C_{c}$, or if the dimensionless acceleration of the driving, $\gamma$, is increased above a value $\gamma_{c}$.