Dual Granular Temperature Oscillation of a Compartmentalized Bidisperse Granular Gas

Abstract

This paper investigates the evolution of granular temperatures for the oscillation of a bidisperse granular mixture in a vertically vibrated two-compartment container. The oscillation describes a periodic switch of light-particle cluster, followed by heavy-particle cluster, from one compartment to the other. We divide one half of a period of granular oscillation into L1-, L2-, and H-stages, depending on which type of particle is jumping over the barrier between the two compartments. The particle tracking velocimetry technique is used to measure particle velocities, from which the granular temperatures of each type of particles in each compartment are obtained. This study demonstrates that a temperature driven mechanism alone cannot explain the phenomenon of granular oscillation. In the H-stage (L2-stage), the difference in temperatures for heavy particles (light particles) between the two compartments is able to drive the particle flow; however, temperature mechanism is not valid in the L1-stage. The granular oscillation is then analyzed by a flux model, which confirms the temperature mechanism in the H- and L2-stages, and suggests that concentration difference could be an alternative factor to drive the light-particle flow in the L1-stage. In addition, a molecular dynamics simulation is also performed to study the evolution of granular oscillation.