Interference between turbulent and molecular diffusion
INFM, Dipartimento di Fisica, Università di Genova - I-16146 Genova, Italy
2 CNRS, Observatoire de Nice - B.P. 4229, 06304 Nice Cedex 4, France
Accepted: 6 February 1997
The problem of the interference between turbulent and molecular diffusion is investigated. A decorrelating mechanism leading to a depletion of turbulent transport was discussed by Saffman (J. Fluid Mech., 8 (1960) 273). We identify another effect associated with anticorrelated regions which leads to enhancement of transport. The competition between these two effects makes it possible to have either constructive or destructive interference, depending on specific flow correlations. We show that the same arguments apply to the interference between turbulent transport and a large-scale mean flow.
PACS: 47.27.Qb – Turbulent diffusion
© EDP Sciences, 1997