Radial propagation of the instability modes observed in a viscoelastic Couette-Taylor flow

Abstract

Experimental investigation of the flow of a high-molecular-mass polymer solution in the Couette-Taylor system with fixed outer cylinder was performed using visualization and particle image velocimetry (PIV) techniques. Spatiotemporal diagrams of the reflected light intensity and of velocity data allow to describe the flow dynamics in the meridional cross section. When the elasticity and inertia effects are comparable (inertioelastic regime), the circular Couette flow bifurcates to standing waves-in the axial direction-called ribbons. These critical waves also propagate in the radial direction toward the outer cylinder. The higher instability mode manifests in form of domains with disordered oscillations separated by fluctuating walls characterized by strong radial inflow.