Nos tutelles

CNRS

Nos partenaires

Rechercher




Accueil du site > Évènements > Séminaires > Séminaires IRPHE > Archives IRPHE > 2015

Mercredi 20 mai 2015 / IRPHE

publié le , mis à jour le

Séminaire exceptionnel IRPHE

Near-field fission dynamics of elongated jets



Orateur : Denisse Sciamarella
LIMSI

Résumé : The slitted orifice formed by a pair of static lips, which was used to represent the glottis in past phonation studies, is a particularly simple and attractive geometry to study non-circular jets. We present experimental evidence that the core of a free continuous jet exiting a nozzle of this kind, can bifurcate and merge before switching axes. Fission and fusion take place in the vicinity of the lips. Axis switching occurs further downstream, following the usual symmetry properties verified by high aspect ratio jets. In order to unveil the dynamics of the bifurcation, the jet is excited at the frequency of the preferred mode using surface dielectric barrier discharge (DBD) plasma actuators. A phase-locked reconstruction of the evolution of the vorticity structures is attained, and used to explain the phenomenon in terms of the Crow instability.

Date et lieu  : le Mercredi 20 Mai 2015 à 11h00, salle de séminaire d’IRPHE