Coupled nonhomogeneous flows and flow-enhanced concentration fluctuations during startup shear of entangled polymer solutions
Michael C. Burroughs, Abhishek Shetty, L. Gary Leal, Matthew E. Helgeson
Abstract
A new type of transient shear banding in entangled polymer solutions observed in Taylor-Couette flow is reported. A novel combination of rheo-particle-tracking-velocimetry and rheo-microscopy reveals that the banded structure correlates with spatial variations in shear-enhanced concentration fluctuations. The results suggest that local concentration fluctuations, enhanced by shear, lead to extra dissipation within the fluid, which increases the effective fluid viscosity that can drive large flow nonuniformities when such dissipation varies spatially within the flow.
Topics & Concepts
DissipationShear (geology)MechanicsShear flowParticle tracking velocimetryShear rateVelocimetryComplex fluidRheologyFlow (mathematics)Couette flowParticle image velocimetryViscosityMaterials scienceShearing (physics)PhysicsThermodynamicsComposite materialTurbulenceRheology and Fluid Dynamics StudiesMaterial Dynamics and PropertiesBlood properties and coagulation