Flow of Dilute Polymer Solutions in Rough Pipes

Nonequilibrium thermodynamics of dilute polymer solutions in flow.

Modern materials processing applications and technologies often occur far from equilibrium. To this end, the processing of complex materials such as polymer melts and nanocomposites generally occurs under strong deformations and flows, conditions under which equilibrium thermodynamics does not apply. As a result, the ability to determine the nonequilibrium thermodynamic properties of polymeric ...

Relaxation of dilute polymer solutions following extensional flow 1

The relaxation of dilute polymer solutions following stretch in uniaxial extensional flow is investigated via Brownian dynamic simulations of a flexible freely-draining bead-rod chain. The bead-rod chain simulations are compared to Brownian dynamic simulations of a FENE dumbbell and numerical calculations of a FENE-PM chain. A universal relaxation curve for the stress decay from steady-state is...

Turbulent flow in smooth and rough pipes.

Recent experiments at Princeton University have revealed aspects of smooth pipe flow behaviour that suggest a more complex scaling than previously noted. In particular, the pressure gradient results yield a new friction factor relationship for smooth pipes, and the velocity profiles indicate the presence of a power-law region near the wall and, for Reynolds numbers greater than about 400x103 (R...

Spectra of turbulence in dilute polymer solutions

Turbulence in dilute polymer solutions when polymers are strongly stretched by the flow is investigated. We establish power-law spectra of velocity, that are not associated with a flux of a conserved quantity, in two cases. First, such spectrum is formed in the elastic waves range of high Reynolds number turbulence of polymer solutions above the coil–stretch transition. Second, such spectrum is...

Turbulent drag reduction with polymer additive in rough pipes