Direct and adjoint global modes of a recirculation bubble: Lift-up and convective non-normalities

O. Marquet 1, * M. Lombardi 1 Jean-Marc Chomaz 1, 2 D. Sipp 1 L. Jacquin 1
* Auteur correspondant
1 Meudon - ONERA - The French Aerospace Lab
2 LadHyX - Laboratoire d'hydrodynamique
Abstract : The stability of the recirculation bubble behind a smoothed backward-facing step is numerically computed. Destabilization occurs first through a stationary three-dimensional mode. Analysis of the direct global mode shows that the instability corresponds to a deformation of the recirculation bubble in which streamwise vortices induce low- and high-speed streaks as in the classical lift-up mechanism. Formulation of the adjoint problem and computation of the adjoint global mode show that both the lift-up mechanism associated with the transport of the base flow by the perturbation and the convective non-normality associated with the transport of the perturbation by the base flow explain the properties of the flow. The lift-up non-normality differentiates the direct and adjoint modes by their component: the direct is dominated by the streamwise component and the adjoint by the cross-stream component. The convective non-normality results in a different localization of the direct and adjoint global modes, respectively downstream and upstream. The implications of these properties for the control problem are considered. Passive control, to be most efficient, should modify the flow inside the recirculation bubble where direct and adjoint global modes overlap, whereas active control, by for example blowing and suction at the wall, should be placed just upstream of the separation point where the pressure of the adjoint global mode is maximum. © 2009 Cambridge University Press.
Type de document :
Article dans une revue
Journal of Fluid Mechanics, Cambridge University Press (CUP), 2009, 622 (march), pp.1-21. 〈10.1017/s0022112008004023〉
Liste complète des métadonnées

Littérature citée [21 références]  Voir  Masquer  Télécharger
https://hal-polytechnique.archives-ouvertes.fr/hal-01021132
Contributeur : Denis Roura <>
Soumis le : mercredi 16 juillet 2014 - 11:08:49
Dernière modification le : jeudi 15 novembre 2018 - 08:36:01
Document(s) archivé(s) le : jeudi 20 novembre 2014 - 16:47:09

Fichier

S0022112008004023a.pdf
Fichiers éditeurs autorisés sur une archive ouverte

Identifiants

Collections

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

Citation

O. Marquet, M. Lombardi, Jean-Marc Chomaz, D. Sipp, L. Jacquin. Direct and adjoint global modes of a recirculation bubble: Lift-up and convective non-normalities. Journal of Fluid Mechanics, Cambridge University Press (CUP), 2009, 622 (march), pp.1-21. 〈10.1017/s0022112008004023〉. 〈hal-01021132〉

Exporter

BibTeX TEI DC DCterms EndNote

Partager

Métriques

Consultations de la notice

452

Téléchargements de fichiers

303

Contact

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