Hostname: page-component-7c8c6479df-8mjnm Total loading time: 0 Render date: 2024-03-29T05:14:13.867Z Has data issue: false hasContentIssue false

Shear effects on passive scalar spectra

Published online by Cambridge University Press:  21 January 2005

A. CELANI
Affiliation:
CNRS, INLN, 1361 Route des Lucioles, F-06560 Valbonne, France CNRS UMR 6202, Observatoire de la Côte d'Azur, B.P. 4229, 06304 Nice Cedex 4, France
M. CENCINI
Affiliation:
Center for Statistical Mechanics and Complexity, INFM Roma 1 and Dipartimento di Fisica, Università di Roma “La Sapienza”, Piazzale Aldo Moro, 2, I-00185 Roma, Italy
M. VERGASSOLA
Affiliation:
CNRS, URA 2171, Institut Pasteur, 28, rue du Dr. Roux, 75724 Paris Cedex 15, France
E. VILLERMAUX
Affiliation:
Univ. Aix Marseille 1, IRPHE, 49, rue Frederic Joliot Curie, F-13384 Marseille 13, France
D. VINCENZI
Affiliation:
CNRS UMR 6202, Observatoire de la Côte d'Azur, B.P. 4229, 06304 Nice Cedex 4, France Dép. de Mathématiques, Univ. de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice, France

Abstract

The effects of a large-scale shear on the energy spectrum of a passively advected scalar field are investigated. The shear is superimposed on a turbulent isotropic flow, yielding an Obukhov–Corrsin $k^{-5/3}$ scalar spectrum at small scales. Shear effects appear at large scales, where a different, anisotropic behaviour is observed. The scalar spectrum is shown to behave as $k^{-4/3}$ for a shear fixed in intensity and direction. For other types of shear characteristics, the slope is generally intermediate between the $-5/3$ Obukhov–Corrsin and the $-1$ Batchelor values. The physical mechanisms at the origin of this behaviour are illustrated in terms of the motion of Lagrangian particles. They provide an explanation for the scalar spectra that are shallow and dependent on the experimental conditions in shear flows at moderate Reynolds numbers.

Type
Papers
Copyright
© 2005 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)