Instability and spatiotemporal rheochaos in a shear-thickening fluid model

School of Physics, University of Edinburgh, JCMB King's Buildings Edinburgh EH9 3JZ, UK

Corresponding author: A.Aradian@ed.ac.uk

Received: 16 February 2005
Accepted: 23 March 2005

Abstract

We model a shear-thickening fluid that combines a tendency to form inhomogeneous, shear-banded flows with a slow relaxational dynamics for fluid microstructure. The interplay between these factors gives rich dynamics, with periodic regimes (oscillating bands, travelling bands, and more complex oscillations) and spatiotemporal rheochaos. These phenomena, arising from constitutive nonlinearity not inertia, can occur even when the steady-state flow curve is monotonic. Our model also shows rheochaos in a low-dimensional truncation where sharply defined shear bands cannot form.