Viscosity enhancement by domains in phase-separating fluids near the critical point: Proposal of critical rheology

Abstract

The shear viscosity is predicted to increase considerably because of domains in critical fluids quenched into the unstable or metastable region. This is because domains can be easily deformed and broken by shear, resulting in great increase of the surface area, near the critical point. The excess viscosity due to domains, Δη, can be of the same order as the viscosity in the one-phase region in the weak-shear case. It exhibits marked non-Newtonian behavior in the strong-shear case. Predictions are also made on a normal-stress effect due to domains.