Department of Physics Papers

Document Type

Journal Article

Date of this Version

9-21-2005

Publication Source

Physical Review E

Volume

72

Issue

3

Start Page

031305-1

Last Page

031305-7

DOI

10.1103/PhysRevE.72.031305

Abstract

The dynamics of one and two identical spheres rolling in a nearly levitating upflow of air obey the Langevin equation and the fluctuation-dissipation relation [Ojha et al. Nature (London) 427, 521 (2004); Phys. Rev. E 71, 016313 (2005)]. To probe the range of validity of this statistical mechanical description, we perturb the original experiments in four ways. First, we break the circular symmetry of the confining potential by using a stadium-shaped trap, and find that the velocity distributions remain circularly symmetric. Second, we fluidize multiple spheres of different density, and find that all have the same effective temperature. Third, we fluidize two spheres of different size, and find that the thermal analogy progressively fails according to the size ratio. Fourth, we fluidize individual grains of aspherical shape, and find that the applicability of statistical mechanics depends on whether or not the grain chatters along its length, in the direction of airflow.

Copyright/Permission Statement

© 2005 American Physical Society. You can view the original article at: https://journals.aps.org/pre/abstract/10.1103/PhysRevE.72.031305

Included in

Physics Commons

Share

COinS
 

Date Posted:10 October 2017

This document has been peer reviewed.