Flow phase diagrams for concentration-coupled shear banding
| dc.creator | Fielding, Suzanne M | |
| dc.creator | Olmsted, Peter D | |
| dc.date | 2003-02-05 | |
| dc.date.accessioned | 2026-07-07T02:49:33Z | |
| dc.date.available | 2026-07-07T02:49:33Z | |
| dc.description | After surveying the experimental evidence for concentration coupling in the shear banding of wormlike micellar surfactant solutions, we present flow phase diagrams spanned by shear stress (or strain-rate) and concentration in the two-fluid, non-local Johnson-Segalman (d-JS-phi) model. We also present macroscopic flow curves for a range of (average) concentrations. For any concentration high enough to give shear banding, the flow curve shows the usual non-analytic kink at the onset of banding, followed by a coexistence ``plateau'' that slopes upwards. As the concentration is reduced, the width of the coexistence regime diminishes, then terminates at a non-equilibrium critical point. We outline the way in which the flow phase diagram can be reconstructed from a family of such flow curves measured for several different average concentrations. This reconstruction could be used to check new measurements of concentration differences between the coexisting bands. Our d-JS-phi model contains two spatial gradient terms describing the interface between the shear bands. The first is in the viscoelastic constitutive equation, with a characteristic (mesh) length, l. The second is in the (generalised) Cahn-Hilliard equation, with the characteristic length, xi, for equilibrium concentration-fluctuations. We show that the phase diagrams depend on the ratio r=l/xi, with loss of unique state selection at r=0. We also give results for the full shear-banded profiles, and study the divergence of the interfacial width at the critical point. | |
| dc.description | 18 pages | |
| dc.identifier | https://arxiv.org/abs/cond-mat/0302098 | |
| dc.identifier | http://arxiv.org/abs/cond-mat/0302098 | |
| dc.identifier | Eur. Phys. J. E 11, 65-83 (2003) | |
| dc.identifier | doi:10.1140/epje/i2002-10128-7 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/20839 | |
| dc.subject | Soft Condensed Matter | |
| dc.title | Flow phase diagrams for concentration-coupled shear banding | |
| dc.type | text |