The Role of Pair Dispersion in Turbulent Flow
Mickaël Bourgoin,1
Nicholas T. Ouellette,2
Haitao Xu,2,3
Jacob Berg,4
Eberhard Bodenschatz2,3*
Mixing and transport in turbulent flows—which have strong
local concentration fluctuations—are essential in many
natural and industrial systems including reactions in chemical
mixers, combustion in engines and burners, droplet formation
in warm clouds, and biological odor detection and chemotaxis.
Local concentration fluctuations, in turn, are intimately tied
to the problem of the separation of pairs of fluid elements.
We have measured this separation rate in an intensely turbulent
laboratory flow and have found, in quantitative agreement with
the seminal predictions of Batchelor, that the initial separation
of the pair plays an important role in the subsequent spreading
of the fluid elements. These results have surprising consequences
for the decay of concentration fluctuations and have applications
to biological and chemical systems.
2 Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853, USA.
3 Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany.
4 Risø National Laboratory, DK-4000 Roskilde, Denmark.
* To whom correspondence should be addressed. E-mail: eberhard.bodenschatz{at}ds.mpg.de
