Active and hibernating turbulence in minimal channel flow of newtonian and polymeric fluids

Phys Rev Lett. 2010 May 28;104(21):218301. doi: 10.1103/PhysRevLett.104.218301. Epub 2010 May 24.

Abstract

Turbulent channel flow of drag-reducing polymer solutions is simulated in minimal flow geometries. Even in the Newtonian limit, we find intervals of "hibernating" turbulence that display many features of the universal maximum drag reduction asymptote observed in polymer solutions: weak streamwise vortices, nearly nonexistent streamwise variations, and a mean velocity gradient that quantitatively matches experiments. As viscoelasticity increases, the frequency of these intervals also increases, while the intervals themselves are unchanged, leading to flows that increasingly resemble maximum drag reduction.