Shear Viscosity in Two-Dimensional Dipole Systems

TL;DR

This paper models shear viscosity in 2D dipole systems using non-equilibrium molecular dynamics, revealing shear thinning effects, influence of screening media, and proposing a universal scaling law for different interactions.

Contribution

It introduces a detailed simulation study of shear viscosity across various regimes and proposes a universal scaling law for dipole interactions in 2D systems.

Findings

Shear thinning observed at low coupling parameters.

Viscosity can increase or decrease due to screening effects.

Universal scaling law for dipole interactions is proposed.

Abstract

The results of modeling shear flows in classical two-dimensional dipole systems are presented. We used the method of non-equilibrium molecular dynamics to calculate the viscosity at various shear rates. The coefficients of shear viscosity are given in the limit of low shear rates for various regimes of interparticle correlation from a weakly correlated gaseous state to a strongly non-ideal liquid state near the crystallization point. The effect of shear thinning in 2D dipole systems is reported at small values of the coupling parameter. In addition, it is shown that dipole systems can become both less and more viscous due to the presence of a screening medium, depending on the degree of interparticle correlation. The optimal simulation parameters are discussed within the framework of the method of nonequilibrium molecular dynamics for determining the shear viscosity of two-dimensional dipole systems. Moreover, we present a simple fitting curve which provides universal scaling law for both bare dipole-dipole interaction and screened dipole-dipole interaction.