Comptes Rendus
Mixing and coherent vortices in turbulent coaxial jets
Comptes Rendus. Mécanique, Volume 333 (2005) no. 8, pp. 622-627.

Direct numerical simulations associated with mixing in constant-density round coaxial jets are performed. They are validated by comparison against laboratory experiments. The mixing process is studied by seeding a passive tracer first in the outer annular jet, then in the inner jet. We demonstrate the important role played by coherent vortices in the mixing mechanisms. The turbulent mixing exhibits an intermittent character as a consequence of fluid ejections caused by the counter-rotating streamwise vortices. We quantify also the domination of the outer jet and show that the fluid issuing from the central jet remains confined.

Nous développons des simulations numériques directes associées au mélange dans des jets ronds coaxiaux de densité uniforme. Ces simulations sont validées par comparaison avec des expériences de laboratoire. Le processus de mélange est étudié en introduisant un traceur passif dans le jet annulaire puis dans le jet central. Nous montrons le rôle important joué par les tourbillons cohérents dans les mécanismes du mélange. Le mélange turbulent présente un caractère intermittent qui est la conséquence d'éjections de fluide causées par les tourbillons longitudinaux contrarotatifs. Nous quantifions également la domination du jet extérieur et montrons que le fluide issu du jet intérieur reste confiné.

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Accepted:
Published online:
DOI: 10.1016/j.crme.2005.07.003
Keywords: Turbulence, Computational fluid mechanics
Mot clés : Turbulence, Mécanique des fluides numérique

Guillaume Balarac 1; Mohamed Si-Ameur 1

1 L.E.G.I., B.P. 53, 38041 Grenoble cedex 09, France
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Guillaume Balarac; Mohamed Si-Ameur. Mixing and coherent vortices in turbulent coaxial jets. Comptes Rendus. Mécanique, Volume 333 (2005) no. 8, pp. 622-627. doi : 10.1016/j.crme.2005.07.003. https://comptes-rendus.academie-sciences.fr/mecanique/articles/10.1016/j.crme.2005.07.003/

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