Fluctuating pressure measurements in a turbulent separation bubble

Julian Trünkle; Abdelouahab Mohammed-Taifour; Julien Weiss

doi:10.1016/j.crme.2015.09.003

Fluctuating pressure measurements in a turbulent separation bubble

Julian Trünkle ¹; Abdelouahab Mohammed-Taifour ¹; Julien Weiss ¹

¹ Laboratoire TFT, École de technologie supérieure, Montréal, QC H3C 1K3, Canada

Comptes Rendus. Mécanique, Volume 344 (2016) no. 1, pp. 60-67.

Abstract (Original language)
Résumé

Fluctuating pressure measurements are performed on the test surface above a pressure-induced, turbulent separation bubble. The Reynolds number of the incoming turbulent boundary layer is ${Re}_{θ} ≃ 5000$ . The results confirm the presence of a low-frequency breathing mode, caused by the contraction and expansion of the bubble, and a medium-frequency shedding mode, caused by the roll-up and shedding of spanwise vortices in the shear layer bordering the recirculating region. The signatures of both modes are shown to be consistent throughout the span of the test section. In addition, another fluctuating mode is observed and related to the presence of slowly rotating vortices close to the test-section sidewalls.

Des mesures de pression instationnaire sont effectuées dans une zone de décollement turbulente générée sur une surface plane par une combinaison de gradients de pression adverse et favorable. Le nombre de Reynolds de la couche limite amont est de ${Re}_{θ} ≃ 5000$ . Les résultats confirment la présence d'un mode de « respiration » basse fréquence causé par la contraction et l'expansion de la zone décollée, ainsi que d'un mode convectif causé par l'enroulement et le lâcher de structures tourbillonaires au sein de la couche de mélange. La signature des deux modes est observée sur toute l'envergure de la surface d'essai. De plus, un troisième mode fluctuant est observé à proximité des parois latérales, relié à la présence de tourbillons trombes.

Received: 2015-04-09
Accepted: 2015-09-11
Published online: 2015-11-11

DOI: 10.1016/j.crme.2015.09.003

Keywords: Turbulence, Separated flows, Unsteady pressure
Mots-clés : Turbulence, Écoulements décollés, Pression instationnaire

Author's affiliations:

Julian Trünkle ¹; Abdelouahab Mohammed-Taifour ¹; Julien Weiss ¹

¹ Laboratoire TFT, École de technologie supérieure, Montréal, QC H3C 1K3, Canada

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     doi = {10.1016/j.crme.2015.09.003},
     language = {en},
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Julian Trünkle; Abdelouahab Mohammed-Taifour; Julien Weiss. Fluctuating pressure measurements in a turbulent separation bubble. Comptes Rendus. Mécanique, Volume 344 (2016) no. 1, pp. 60-67. doi : 10.1016/j.crme.2015.09.003. https://comptes-rendus.academie-sciences.fr/mecanique/articles/10.1016/j.crme.2015.09.003/

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Cited by Sources:

^☆ A related version of this article was first presented at the 50th 3AF International Conference on Applied Aerodynamics (Toulouse, France) on March 30th, 2015.

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