Geometric scaling of purely-elastic flow instabilities

TL;DR

This study investigates how the geometry of serpentine channels influences the onset of purely-elastic flow instabilities through experiments, simulations, and theory, revealing consistent scaling behavior.

Contribution

It provides a comprehensive analysis combining experimental, numerical, and theoretical approaches to understand geometric scaling in elastic flow instabilities.

Findings

Qualitative agreement between experiments and simulations.

Validation of the Pakdel-McKinley criterion for instability onset.

Identification of geometric parameters affecting instability.

Abstract

We present a combined experimental, numerical and theoretical investigation of the geometric scaling of the onset of a purely-elastic flow instability in a serpentine channel. Good qualitative agreement is obtained between experiments, using dilute solutions of flexible polymers in microfluidic devices, and two-dimensional numerical simulations using the UCM model. The results are confirmed by a simple theoretical analysis, based on the dimensionless criterion proposed by Pakdel-McKinley for onset of a purely-elastic instability.