Atomic-scale structure of hard-core fluids under shear flow

TL;DR

This paper investigates how shear flow affects the atomic-scale structure of hard-sphere fluids, using theoretical approximations validated by molecular dynamics simulations to understand density correlations under nonequilibrium conditions.

Contribution

It introduces a nonequilibrium generalized mean spherical approximation for the pair distribution function in sheared hard-sphere fluids, validated against simulations.

Findings

Good agreement between theory and simulations below shear-induced ordering transition

Enskog approximation accurately predicts contact pair distribution function under shear

Generalized mean spherical approximation extends understanding of nonequilibrium fluid structure

Abstract

The effect of velocity correlations on the equal-time density autocorrelation function, e.g. the pair distribution function or pdf, of a hard-sphere fluid undergoing shear flow is investigated. The pdf at contact is calculated within the Enskog approximation and is shown to be in good agreement with molecular dynamics simulations for shear rates below the shear-induced ordering transition. These calculations are used to construct a nonequilibrium generalised mean spherical approximation for the pdf at finite separations which is also found to agree well with the simulation data.