Nonlinear evolution of the zigzag instability in stratified fluids: A shortcut on the route to dissipation

Axel Deloncle 1, * Paul Billant 1 Jean-Marc Chomaz 1
* Auteur correspondant
1 LadHyX - Laboratoire d'hydrodynamique
Abstract : We present high-resolution direct numerical simulations of the nonlinear evolution of a pair of counter-rotating vertical vortices in a stratified fluid for various high Reynolds numbers Re and low Froude numbers Fh. The vortices are bent by the zigzag instability producing high vertical shear. There is no nonlinear saturation so that the exponential growth is stopped only when the viscous dissipation by vertical shear is of the same order as the horizontal transport, i.e. when Zmaxh/Re = O(1) where Zmaxh is the maximum horizontal enstrophy non-dimensionalized by the vortex turnover frequency. The zigzag instability therefore directly transfers the energy from large scales to the small dissipative vertical scales. However, for high Reynolds number, the vertical shear created by the zigzag instability is so intense that the minimum local Richardson number Ri decreases below a threshold of around 1/4 and small-scale Kelvin-Helmholtz instabilities develop. We show that this can only occur when ReFh2 is above a threshold estimated as 340. Movies are available with the online version of the paper. © 2008 Cambridge University Press.
Type de document :
Article dans une revue
Journal of Fluid Mechanics, Cambridge University Press (CUP), 2008, 599 (mars), pp.229-239. 〈10.1017/s0022112007000109〉
Liste complète des métadonnées

Littérature citée [17 références]  Voir  Masquer  Télécharger
https://hal-polytechnique.archives-ouvertes.fr/hal-01022803
Contributeur : Denis Roura <>
Soumis le : lundi 21 juillet 2014 - 11:58:06
Dernière modification le : jeudi 7 février 2019 - 16:58:45
Document(s) archivé(s) le : jeudi 20 novembre 2014 - 18:13:40

Fichier

S0022112007000109a.pdf
Fichiers éditeurs autorisés sur une archive ouverte

Identifiants

Collections

X-LADHYX | X | PARISTECH | X-DEP-MECA

Citation

Axel Deloncle, Paul Billant, Jean-Marc Chomaz. Nonlinear evolution of the zigzag instability in stratified fluids: A shortcut on the route to dissipation. Journal of Fluid Mechanics, Cambridge University Press (CUP), 2008, 599 (mars), pp.229-239. 〈10.1017/s0022112007000109〉. 〈hal-01022803〉

Exporter

BibTeX TEI DC DCterms EndNote

Partager

Métriques

Consultations de la notice

190

Téléchargements de fichiers

93

Contact

support.ccsd.cnrs.fr
hal.support@ccsd.cnrs.fr
Logo CCSD