# Disorder suppresses chaos in viscoelastic flows

## TL;DR

This study demonstrates that geometric disorder in microfluidic arrays can significantly delay or suppress chaotic flow behaviors in viscoelastic fluids by shifting the flow from extension-dominated to shear-dominated regimes.

## Contribution

It reveals how geometric disorder influences flow stability in viscoelastic systems, showing that increased disorder suppresses chaos and alters flow type.

## Key findings

- Small disorder delays chaos onset.
- Large disorder suppresses chaotic fluctuations.
- Flow shifts from extension to shear dominance with disorder.

## Abstract

Viscoelastic flows transition from steady to time-dependent, chaotic dynamics under critical flow conditions, but the implications of geometric disorder for flow stability in these systems are unknown. Utilizing microfluidics, we flow a viscoelastic fluid through arrays of cylindrical pillars, which are perturbed from a hexagonal lattice with various degrees of geometric disorder. Small disorder, corresponding to ~ 10% of the lattice constant, delays the transition to higher flow speeds, while larger disorders exhibit near-complete suppression of chaotic velocity fluctuations. We show that the mechanism facilitating flow stability at high disorder is rooted in a shift from extension-dominated to shear-dominated flow type with increasing disorder.