Noise small-correlation-time effects on the dispersion of passive scalars
INFM - Dipartimento di Fisica, Università “La Sapienza” - I-00185 Roma, Italy
2 CNRS, Observatoire de Nice, B.P. 4229 - 06304 Nice Cedex 4, France INFM - Dipartimento di Fisica, Università di Genova - I-16146 Genova, Italy
Accepted: 8 July 1998
The effect of a small correlation time, τ, of the (colored-) small-scales noise on the effective diffusivities for the transport of passive scalars is investigated. It has recently been shown that the presence of τ makes the transport problem equivalent to the white-in-time case provided by a renormalized advecting velocity field. This equivalence is here exploited to investigate, both analytically and perturbatively in the Strouhal number of the advecting velocity field, the mechanism responsible for enhancement of transport.
PACS: 47.27.Qb – Turbulent diffusion
© EDP Sciences, 1998