Taylor-like vortices in the shear-banding flow of giant micelles

TL;DR

This study visualizes Taylor-like vortices in shear-banding flows of giant micelles, revealing their formation, dynamics, and transition to unsteady states, with implications for understanding complex fluid behaviors.

Contribution

First demonstration of Taylor-like vortices in shear-banding flow of giant micelles using flow visualization techniques.

Findings

Vortices form in the shear band and are linked to interface undulations.

Vortex dynamics correlate with interface motion.

Transition from steady vortices to dynamic vortex creation/destruction with increased control parameter.

Abstract

Using flow visualizations in Couette geometry, we demonstrate the existence of Taylor-like vortices in the shear-banding flow of a giant micelles system. We show that vortices stacked along the vorticity direction develop concomitantly with interfacial undulations. These cellular structures are mainly localized in the induced band and their dynamics is fully correlated with that of the interface. As the control parameter increases, we observe a transition from a steady vortex flow to a state where pairs of vortices are continuously created and destroyed. Normal stress effects are discussed as potential mechanisms driving the three-dimensional flow.