Particle shapes leading to Newtonian dilute suspensions

TL;DR

This paper investigates how particle shape influences the rheological behavior of dilute suspensions, identifying symmetry conditions that ensure Newtonian behavior across strain sizes and introducing new particle shapes with this property.

Contribution

It introduces symmetry-based criteria and constructs novel particle shapes that guarantee Newtonian rheology in dilute suspensions.

Findings

Symmetry conditions for Newtonian behavior at all strains.

New particle shapes that exhibit Newtonian behavior at small strains.

Criteria applicable to design of particle suspensions with predictable rheology.

Abstract

It is well known that suspensions of particles in a viscous fluid can affect the rheology significantly, producing a pronounced non-Newtonian response even in dilute suspension. However, it is unclear a priori which particle shapes lead to this behaviour. We present two simple symmetry conditions on the shape which are sufficient for a dilute suspension to be Newtonian for all strain sizes and one sufficient for Newtonian behavior for small strains. We also construct a class of shapes out of thin, rigid rods not found by the symmetry argument which share this property for small strains.