Turbulent drag reduction by flexible and rodlike polymers: Crossover effects at small concentrations.
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 crossover 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 crossover phenomenology.
Ching
Emily S C
ES
Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong.
Lo
T S
TS
Procaccia
Itamar
I