# Steady streaming flows in viscoelastic liquids

## TL;DR

This study investigates how viscoelastic properties of polymer solutions affect steady streaming flows in microfluidic devices, revealing both similarities to Newtonian fluids and unique behaviors in shear-thinning elastic liquids.

## Contribution

It provides experimental insights into the influence of non-Newtonian rheology on steady streaming, highlighting new flow behaviors in shear-thinning elastic liquids.

## Key findings

- Velocity profiles in elastic liquids with constant viscosity resemble Newtonian flows.
- Shear-thinning elastic liquids show non-monotonic streaming layer evolution with frequency.
- High-frequency flows exhibit flow profile asymmetry.

## Abstract

We discuss experimental investigations on steady streaming flows of dilute and semi-dilute polymer solutions in microfluidic devices. The effect of non-Newtonian behavior on steady streaming for different model fluids is determined by characterizing the evolution of the inner streaming layer as a function of oscillation frequency using particle tracking velocimetry. We find that steady streaming velocity profiles in constant-viscosity elastic liquids are qualitatively similar to those in Newtonian liquids. Steady streaming velocity profiles in elastic liquids with strong shear thinning, however, display two unique features: (i) a non-monotonic evolution of the inner streaming layer with increasing frequency, first growing then decreasing in width, and (ii) a clear asymmetry in the flow profile at high frequencies.