# Emergence of chaos in a viscous solution of rods

## TL;DR

Adding microscopic rods to a viscous fluid at low Reynolds number induces a transition from laminar to chaotic flow, significantly increasing flow resistance and enhancing mixing efficiency through flow instabilities.

## Contribution

This paper demonstrates that microscopic rods cause flow instabilities leading to chaos in viscous fluids, revealing a new mechanism for flow transition and mixing enhancement.

## Key findings

- Flow resistance increases with rod addition.
- Transition from laminar to chaotic flow observed.
- Flow instabilities activate multiple scales for mixing.

## Abstract

It is shown that the addition of small amounts of microscopic rods in a viscous fluid at low Reynolds number causes a significant increase of the flow resistance. Numerical simulations of the dynamics of the solution reveal that this phenomenon is associated to a transition from laminar to chaotic flow. Polymer stresses give rise to flow instabilities which, in turn, perturb the alignment of the rods. This coupled dynamics results in the activation of a wide range of scales, which enhances the mixing efficiency of viscous flows.