Turbulent Drag Reduction by Flexible and Rodlike Polymers: Crossover Effects at Small Concentrations

Abstract

Drag reduction by polymers is bounded between two universal asymptotes, the von-Kármán log-law of the law and the Maximum Drag Reduction (MDR) asymptote. It is theoretically understood why the MDR asymptote is universal, independent of whether the polymers are flexible or rodlike. The cross-over behavior from the Newtonian von-Kármán log-law to the MDR is however not universal, showing different characteristics for flexible and rodlike polymers. In this paper we provide a theory for this cross-over phenomenology.

5 pages, 4 figures, submitted to Physical Review E

References in corpus (1)

• Drag Reduction by Polymers in Wall Bounded Turbulence

Cited by in corpus (3)

• Colloquium: Theory of Drag Reduction by Polymers in Wall Bounded Turbulence
• Emergence of chaos in a viscous solution of rods
• Orientational order and topological defects in a dilute solutions of rodlike polymers at low Reynolds number