Active and passive fields face to face
- Others:
- Institut Non Linéaire de Nice Sophia-Antipolis (INLN) ; Université Nice Sophia Antipolis (1965 - 2019) (UNS) ; COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)
- Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE) ; Université Nice Sophia Antipolis (1965 - 2019) (UNS) ; COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur ; COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
- Dipartimento di Fisica, Center for Statistical Mechanics and Complexity ; Università degli Studi di Roma "La Sapienza" = Sapienza University [Rome] (UNIROMA)- Istituto Nazionale di Fisica Nucleare (INFN)
- Dipartimento di Fisica ; Università degli studi di Genova = University of Genoa (UniGe)
- Istituto Nazionale di Fisica Nucleare (INFN) ; Istituto Nazionale di Fisica Nucleare (INFN)
Description
The statistical properties of active and passive scalar fields transported by the same turbulent flow are investigated. Four examples of active scalar have been considered: temperature in thermal convection, magnetic potential in two-dimensional magnetohydrodynamics, vorticity in two-dimensional Ekman turbulence and potential temperature in surface flows. In the cases of temperature and vorticity, it is found that the active scalar behavior is akin to that of its co-evolving passive counterpart. The two other cases indicate that this similarity is in fact not generic and differences between passive and active fields can be striking: in two-dimensional magnetohydrodynamics the magnetic potential performs an inverse cascade while the passive scalar cascades toward the small-scales; in surface flows, albeit both perform a direct cascade, the potential temperature and the passive scalar have different scaling laws already at the level of low-order statistical objects. These dramatic differences are rooted in the correlations between the active scalar input and the particle trajectories. The role of such correlations in the issue of universality in active scalar transport and the behavior of dissipative anomalies is addressed.
Abstract
36 pages, 20 eps figures, for the published version see http://www.iop.org/EJ/abstract/1367-2630/6/1/072
Additional details
- URL
- https://hal.archives-ouvertes.fr/hal-00015310
- URN
- urn:oai:HAL:hal-00015310v1
- Origin repository
- UNICA