Title :

Unsteady behavior in forced ow over a backward-facing step

Author(s) :

Chovet, Camila [Auteur]
Laboratoire d'Automatique, de Mécanique et d'Informatique industrielles et Humaines - UMR 8201 [LAMIH]
Lippert, Marc [Auteur]
Laboratoire d'Automatique, de Mécanique et d'Informatique industrielles et Humaines - UMR 8201 [LAMIH]
Keirsbulck, Laurent [Auteur]
Laboratoire d'Automatique, de Mécanique et d'Informatique industrielles et Humaines - UMR 8201 [LAMIH]
Foucaut, Jean-Marc [Auteur]
Laboratoire de Mécanique des Fluides de Lille – Kampé de Fériet - UMR 9014 [LMFL]

Journal title :

Flow, Turbulence and Combustion

Pages :

145-165

Publisher :

Springer Verlag (Germany)

Publication date :

2019

ISSN :

1386-6184

HAL domain(s) :

Physique [physics]
Sciences de l'ingénieur [physics]
Sciences de l'ingénieur [physics]/Milieux fluides et réactifs

English abstract : [en]

The unsteady behavior of a turbulent ow over a backward-facing step was investigated under controlled actuation at a Re h = 31500. Initial measurements were made changing the periodic forcing frequency St a from 0.045 to ...
Show more >The unsteady behavior of a turbulent ow over a backward-facing step was investigated under controlled actuation at a Re h = 31500. Initial measurements were made changing the periodic forcing frequency St a from 0.045 to 0.453. The best forcing frequency was observed at a dimensionless frequency of St a = 0.226 and is associated with the shedding frequency. This frequency can eectively reduce the reattachment length and thus the recirculation area. A further study of the dynamical aspects of the un-actuated and actuated ows is also presented. The velocity elds were measured using a particle image velocimetry (Piv) system. Pod techniques were used to analyze the ow. With this procedure, the pressure uctuation power spectra was separated in 5 dierent modes. The two rst modes contained a predominant peak at around 0.12 corresponding to the apping motion (low frequency of the large scale structures). The other modes (from 3 to 5) showed a transitional and increasing peak that is related to the shedding phenomena. Results suggest that an excitation on the shedding frequency leads to a decrease of the external separation length L r , an increase of the internal separation length X r and a further decrease of the recirculation area.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

Collections :

• Laboratoire de Mécanique des Fluides de Lille Kampé de Fériet (LMFL) - UMR 9014

Source :

Harvested from HAL