The role of pair dispersion in turbulent flow

Mickaël Bourgoin (1) , Nicholas T. Ouellette (2) , Haitao Xu (2) , Jacob Berg (3) , Eberhard Bodenschatz (2, 4)

1 LEGI - Laboratoire des Écoulements Géophysiques et Industriels [Grenoble]
2 LASSP - Laboratory of Atomic and Solid State Physics [Ithaca]
3 Risø National Laboratory
4 MPIDS - Max Planck Institute for Dynamics and Self-Organization

Mixing and transport in turbulent flows - which have strong local concentration fluctuations - 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 rote 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.

Domaines: Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]

Mickaël Bourgoin, Nicholas T. Ouellette, Haitao Xu, Jacob Berg, Eberhard Bodenschatz. The role of pair dispersion in turbulent flow. Science, 2006, 311 (5762), pp.835-838. ⟨10.1126/science.1121726⟩. ⟨hal-00492363⟩