Imperfect supercritical bifurcation in a three-dimensional turbulent wake

Abstract : The turbulent wake of a square-back body exhibits a strong bimodal behavior. The wake randomly undergoes symmetry-breaking reversals between two mirror asymmetric steady modes [reflectional symmetry-breaking (RSB) modes]. The characteristic time for reversals is about 2 or 3 orders of magnitude larger than the natural time for vortex shedding. Studying the effects of the proximity of a ground wall together with the Reynolds number, it is shown that the bimodal behavior is the result of an imperfect pitchfork bifurcation. The RSB modes correspond to the two stable bifurcated branches resulting from an instability of the stable symmetric wake. An attempt to stabilize the unstable symmetric wake is investigated using a passive control technique. Although the controlled wake still exhibits strong fluctuations, the bimodal behavior is suppressed and the drag reduced. This promising experiment indicates the possible existence of an unstable solution branch corresponding to a reflectional symmetry preserved (RSP) mode. This work is encouraging to develop a control strategy based on a stabilization of this RSP mode to reduce mean drag and lateral force fluctuations.
Type de document :
Article dans une revue
Physical Review Online Archive (PROLA), American Physical Society, 2015, pp.063005. 〈10.1103/PhysRevE.91.063005〉
Liste complète des métadonnées

Littérature citée [15 références]  Voir  Masquer  Télécharger

https://hal-ensta.archives-ouvertes.fr/hal-01164472
Contributeur : Olivier Cadot <>
Soumis le : mercredi 17 juin 2015 - 16:58:39
Dernière modification le : mardi 20 novembre 2018 - 14:04:02
Document(s) archivé(s) le : mardi 15 septembre 2015 - 17:36:08

Fichier

Bifurcation.pdf
Fichiers produits par l'(les) auteur(s)

Identifiants

Citation

Olivier Cadot, Antoine Evrard, Luc Pastur. Imperfect supercritical bifurcation in a three-dimensional turbulent wake. Physical Review Online Archive (PROLA), American Physical Society, 2015, pp.063005. 〈10.1103/PhysRevE.91.063005〉. 〈hal-01164472〉

Partager

Métriques

Consultations de la notice

186

Téléchargements de fichiers

223