Criterion for purely elastic Taylor-Couette instability in the flows of shear-banding fluids

• Published in: Europhysics letters Vol. 96; no. 4; pp. 44004 - 44009
• Main Authors: Fardin, M. A., Ober, T. J., Gay, C., Grégoire, G., McKinley, G. H., Lerouge, S.
• Format: Journal Article
• Language: English
• Published: EPS, SIF, EDP Sciences and IOP Publishing 01.11.2011; European Physical Society / EDP Sciences / Società Italiana di Fisica / IOP Publishing
• Subjects: 47.20.-k; 47.50.-d; 83.60.-a; Condensed Matter; Fluid Dynamics; Physics; Soft Condensed Matter
• ISSN: 0295-5075; 1286-4854
• DOI: 10.1209/0295-5075/96/44004

In the past twenty years, shear-banding flows have been probed by various techniques, such as rheometry, velocimetry and flow birefringence. In micellar solutions, many of the data collected exhibit unexplained spatio-temporal fluctuations. Recently, it has been suggested that those fluctuations originate from a purely elastic instability of the flow. In cylindrical Couette geometry, the instability is reminiscent of the Taylor-like instability observed in viscoelastic polymer solutions. In this letter, we describe how the criterion for purely elastic Taylor-Couette instability should be adapted to shear-banding flows. We derive three categories of shear-banding flows with curved streamlines, depending on their stability.