Intrinsic viscosity of a suspension of weakly Brownian ellipsoids in shear

TL;DR

This study investigates how weak thermal noise influences the angular dynamics and intrinsic viscosity of dilute suspensions of triaxial ellipsoids in shear flow, revealing shape-dependent effects and the impact of axisymmetry breaking.

Contribution

It provides a numerical analysis of the steady angular distribution and intrinsic viscosity of triaxial ellipsoids, highlighting the shape dependence and effects of weak thermal noise.

Findings

Intrinsic viscosity is less sensitive to shape than deterministic angular dynamics.

Suspensions of rod-like particles are most affected by axisymmetry breaking.

Intrinsic viscosity of triaxial particles is smaller than that of axisymmetric particles with same volume.

Abstract

We analyze the angular dynamics of triaxial ellipsoids in a shear flow subject to weak thermal noise. By numerically integrating an overdamped angular Langevin equation, we find the steady angular probability distribution for a range of triaxial particle shapes. From this distribution we compute the intrinsic viscosity of a dilute suspension of triaxial particles. We determine how the viscosity depends on particle shape in the limit of weak thermal noise. While the deterministic angular dynamics depends very sensitively on particle shape, we find that the shape dependence of the intrinsic viscosity is weaker, in general, and that suspensions of rod-like particles are the most sensitive to breaking of axisymmetry. The intrinsic viscosity of a dilute suspension of triaxial particles is smaller than that of a suspension of axisymmetric particles with the same volume, and the same ratio of major to minor axis lengths.