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LES predictions of noise emissions from a low-bypass ratio military gas turbine engine / N. Sinha in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 4 (Avril 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 4 (Avril 2011) . - 10 p. Titre : LES predictions of noise emissions from a low-bypass ratio military gas turbine engine Type de document : texte imprimé Auteurs : N. Sinha, Auteur ; J. Erwin, Auteur ; C. Kannepalli, Auteur Année de publication : 2012 Article en page(s) : 10 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Aeroacoustics  Boundary  layer  turbulence  Engines  Flow  simulation  Gas  turbines  Jets  Military  aircraft  Navier-Stokes  equations  Nozzles  Propulsion  Shear  flow Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A practical framework for predicting jet structure and noise from military aircraft is described, which is developmental and has been examined for some fundamental jet flow problems. The framework currently utilizes Reynolds-averaged Navier Stokes (RANS) methodology for geometrically complex internal propulsive flowpaths and large eddy simulation (LES) methodology for the jet structure downstream of the nozzle exit. Temporal data from the LES solution is stored on a flared-cylindrical surface surrounding the jet, to be used for noise propagation to the farfield. Earlier applications of RANS methodology combined with the use of analogy-based jet noise codes proved inadequate due to the inability of the noise codes to treat complex 3D flows, such as those associated with multiple nozzles and/or with varied jet noise reduction concepts. Restricting the use of LES (or RANS/LES), methodology to free shear flows remedies the severe grid resolution issues that would be encountered with utilization of LES for modeling internal propulsive flows. The issue of “adequately” initiating the LES solution from a RANS solution profile just downstream of the nozzle exit has been the focus of our exploratory studies and is clearly more complex than standard procedures, such as recycling and rescaling techniques used for simple wall bounded flows. Approaches examined are discussed and unified RANS/LES solutions for several flows are described. The application of this framework to more complex flows requires no fundamental modifications as will also be discussed. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] LES predictions of noise emissions from a low-bypass ratio military gas turbine engine [texte imprimé] / N. Sinha, Auteur ; J. Erwin, Auteur ; C. Kannepalli, Auteur . - 2012 . - 10 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 4 (Avril 2011) . - 10 p. Mots-clés : Aeroacoustics  Boundary  layer  turbulence  Engines  Flow  simulation  Gas  turbines  Jets  Military  aircraft  Navier-Stokes  equations  Nozzles  Propulsion  Shear  flow Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A practical framework for predicting jet structure and noise from military aircraft is described, which is developmental and has been examined for some fundamental jet flow problems. The framework currently utilizes Reynolds-averaged Navier Stokes (RANS) methodology for geometrically complex internal propulsive flowpaths and large eddy simulation (LES) methodology for the jet structure downstream of the nozzle exit. Temporal data from the LES solution is stored on a flared-cylindrical surface surrounding the jet, to be used for noise propagation to the farfield. Earlier applications of RANS methodology combined with the use of analogy-based jet noise codes proved inadequate due to the inability of the noise codes to treat complex 3D flows, such as those associated with multiple nozzles and/or with varied jet noise reduction concepts. Restricting the use of LES (or RANS/LES), methodology to free shear flows remedies the severe grid resolution issues that would be encountered with utilization of LES for modeling internal propulsive flows. The issue of “adequately” initiating the LES solution from a RANS solution profile just downstream of the nozzle exit has been the focus of our exploratory studies and is clearly more complex than standard procedures, such as recycling and rescaling techniques used for simple wall bounded flows. Approaches examined are discussed and unified RANS/LES solutions for several flows are described. The application of this framework to more complex flows requires no fundamental modifications as will also be discussed. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]