Torque in Taylor–Couette flow of viscoelastic polymer solutions

Borja Martínez-Arias , Jorge Peixinho (1)

1 LOMC - Laboratoire Ondes et Milieux Complexes

When a polymer solution is sheared between concentric cylinders, with the inner rotating and the outer fixed, the torque on the inner cylinder is modified compared to a Newtonian fluid of the same viscosity revealing the di↵erent flow patterns that emerge above the linear stability threshold for circular Couette flow. Here, mixtures of relatively short and long linear polymers in dilute and semi-dilute concentrations were considered. Their shear viscosity and extensional relaxation time are quantified. The stability of the flow is monitored through torque measurements and flow visualisations for a constant rate of acceleration and deceleration of the inner cylinder in a wide range of polymer concentrations. The torque exhibits an hysteretic behaviour, typical of subcritical transition. For large concentrations, six di↵erent numbers of steady solitary pairs of vortices, called diwhirls, were observed depending on the deceleration rate and their torque contribution is reported.

Keywords: Torque; Taylor-Couette flow; Rheology of polymer solutions

Domains: Physics [physics]; Engineering Sciences [physics]

Borja Martínez-Arias, Jorge Peixinho. Torque in Taylor–Couette flow of viscoelastic polymer solutions. Journal of Non-Newtonian Fluid Mechanics, 2017, 247, pp.221 - 228. ⟨10.1016/j.jnnfm.2017.07.005⟩. ⟨hal-01919472⟩