Shear Viscosity of the Hard-Sphere Fluid via Nonequilibrium Molecular Dynamics

Abstract

The shear viscosity $\ensuremath{\eta}$ of the hard-sphere fluid, at volumes of 1.6 and 2 times the close-packed volume, is computed with use of nonequilibrium molecular dynamics. At high shear rate $\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{\ensuremath{\epsilon}}$ we observe a phase transition in which the system undergoes two-dimensional ordering in the plane perpendicular to the flow, accompanied by a sharp decrease in $\ensuremath{\eta}$. For small $\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{\ensuremath{\epsilon}}$, no evidence is found for the square-root dependence on $\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{\ensuremath{\epsilon}}$ reported by previous investigators.