Energy nonequipartition in a sheared granular mixture

TL;DR

This paper investigates how kinetic temperatures differ in a sheared granular mixture, revealing non-equipartition effects influenced by restitution and mixture parameters, validated by analytical and simulation methods.

Contribution

It provides an analytical framework for predicting temperature ratios in sheared granular mixtures using Sonine polynomial expansion and compares results with Monte Carlo simulations.

Findings

Temperature ratio deviates from unity under shear.

Strong dependence on restitution coefficients and mixture parameters.

Excellent agreement between theory and simulations.

Abstract

The kinetic granular temperatures of a binary granular mixture in simple shear flow are determined from the Boltzmann kinetic theory by using a Sonine polynomial expansion. The results show that the temperature ratio is clearly different from unity (as may be expected since the system is out of equilibrium) and strongly depends on the restitution coefficients as well as on the parameters of the mixture. The approximate analytical calculations are compared with those obtained from Monte Carlo simulations of the Boltzmann equation showing an excellent agreement over the range of parameters investigated. Finally, the influence of the temperature differences on the rheological properties is also discussed.