Low pressure turbine relaminarization bubble characterization using Massively-parallel large Eddy simulations / Shriram Jagannathan in Transactions of the ASME . Journal of fluids engineering, Vol. 134 N° 2 (Fevrier 2012)  

Public ISBD [article]  inTransactions of the ASME . Journal of fluids engineering > Vol. 134 N° 2 (Fevrier 2012) . - 13 p. Titre : Low pressure turbine relaminarization bubble characterization using Massively-parallel large Eddy simulations Type de document : texte imprimé Auteurs : Shriram Jagannathan, Auteur ; Markus Schwänen, Auteur ; Andrew Duggleby, Auteur Année de publication : 2012 Article en page(s) : 13 p. Note générale : Fluids engineering Langues : Anglais (eng) Mots-clés : Low pressure turbine Large-eddy simulation Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The separation and reattachment of suction surface boundary layer in a low pressure turbine is characterized using large-eddy simulation at Ress = 69000 based on inlet velocity and suction surface length. Favorable comparisons are drawn with experiments using a high pass filtered Smagorinsky model for sub-grid scales. The onset of time mean separation is at s/so = 0.61 and reattachment at s/so = 0.81, extending over 20% of the suction surface. The boundary layer is convectively unstable with a maximum reverse flow velocity of about 13% of freestream. The breakdown to turbulence occurs over a very short distance of suction surface and is followed by reattachment. Turbulence near the bubble is further characterized using anisotropy invariant mapping and time orthogonal decomposition diagnostics. Particularly the vortex shedding and shear layer flapping phenomena are addressed. On the suction side, dominant hairpin structures near the transitional and turbulent flow regime are observed. The hairpin vortices are carried by the freestream even downstream of the trailing edge of the blade with a possibility of reaching the next stage. Longitudinal streaks that evolve from the breakdown of hairpin vortices formed near the leading edge are observed on the pressure surface. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JFEGA4000134000002 [...] [article] Low pressure turbine relaminarization bubble characterization using Massively-parallel large Eddy simulations [texte imprimé] / Shriram Jagannathan, Auteur ; Markus Schwänen, Auteur ; Andrew Duggleby, Auteur . - 2012 . - 13 p. Fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 134 N° 2 (Fevrier 2012) . - 13 p. Mots-clés : Low pressure turbine Large-eddy simulation Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The separation and reattachment of suction surface boundary layer in a low pressure turbine is characterized using large-eddy simulation at Ress = 69000 based on inlet velocity and suction surface length. Favorable comparisons are drawn with experiments using a high pass filtered Smagorinsky model for sub-grid scales. The onset of time mean separation is at s/so = 0.61 and reattachment at s/so = 0.81, extending over 20% of the suction surface. The boundary layer is convectively unstable with a maximum reverse flow velocity of about 13% of freestream. The breakdown to turbulence occurs over a very short distance of suction surface and is followed by reattachment. Turbulence near the bubble is further characterized using anisotropy invariant mapping and time orthogonal decomposition diagnostics. Particularly the vortex shedding and shear layer flapping phenomena are addressed. On the suction side, dominant hairpin structures near the transitional and turbulent flow regime are observed. The hairpin vortices are carried by the freestream even downstream of the trailing edge of the blade with a possibility of reaching the next stage. Longitudinal streaks that evolve from the breakdown of hairpin vortices formed near the leading edge are observed on the pressure surface. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JFEGA4000134000002 [...]

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