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The influence of compressibility on the aerodynamics of an inverted wing in ground effect / Doig, Graham in Transactions of the ASME . Journal of fluids engineering, Vol. 133 N° 6 (Juin 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of fluids engineering > Vol. 133 N° 6 (Juin 2011) . - 12 p. Titre : The influence of compressibility on the aerodynamics of an inverted wing in ground effect Type de document : texte imprimé Auteurs : Doig, Graham, Auteur ; Barber, Tracie J., Auteur ; Neely, Andrew J., Auteur Année de publication : 2011 Article en page(s) : 12 p. Note générale : Fluids engineering Langues : Anglais (eng) Mots-clés : Aerodynamics  Compressible  flow  Computational  fluid  dynamics  Drag  Flow  simulation  Mach  number  Shock  waves  Subsonic  flow  Supersonic  flow  Vortices Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : For inverted wings in close ground proximity, such as race car configurations, the aerodynamic ground effect can produce local velocities significantly greater than the freestream and the effects of compressibility may occur sooner than would be expected for a wing that is not close to a ground plane. A three-dimensional computational fluid dynamics study was conducted, involving a modified NASA GA(W)-2 LS [1]-0413 MOD inverted wing with an endplate, to investigate the onset and significance of compressibility for low subsonic Mach numbers. With the wing angle of incidence fixed, Mach numbers from 0.088 to 0.4 were investigated, at ground clearances ranging from infinite (free flight) to a height-to-chord clearance of 0.067. The freestream Mach number at which flow compressibility significantly affects the predicted aerodynamic coefficients was identified to be as low as 0.15. Beyond this point, as the compressible flow conditions around the wing result in changed pressure distribution and separation behavior, treating the flow as incompressible becomes inappropriate and leads to consistent underprediction of lift and drag. The influence on primary vortex behavior of density changes around the wing was found to be relatively inconsequential even at the higher end of the Mach scale investigated. By a freestream Mach number of 0.4 and at low clearances, local supersonic flow regions were established close to the suction peak of the lower wing surface in compressible simulations; the formation of a normal shock wave between the wing and the ground was shown to result in significant increases in separation and therefore overall drag, as well as a distinct loss of downforce. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JFEGA400013 [...] [article] The influence of compressibility on the aerodynamics of an inverted wing in ground effect [texte imprimé] / Doig, Graham, Auteur ; Barber, Tracie J., Auteur ; Neely, Andrew J., Auteur . - 2011 . - 12 p. Fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 133 N° 6 (Juin 2011) . - 12 p. Mots-clés : Aerodynamics  Compressible  flow  Computational  fluid  dynamics  Drag  Flow  simulation  Mach  number  Shock  waves  Subsonic  flow  Supersonic  flow  Vortices Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : For inverted wings in close ground proximity, such as race car configurations, the aerodynamic ground effect can produce local velocities significantly greater than the freestream and the effects of compressibility may occur sooner than would be expected for a wing that is not close to a ground plane. A three-dimensional computational fluid dynamics study was conducted, involving a modified NASA GA(W)-2 LS [1]-0413 MOD inverted wing with an endplate, to investigate the onset and significance of compressibility for low subsonic Mach numbers. With the wing angle of incidence fixed, Mach numbers from 0.088 to 0.4 were investigated, at ground clearances ranging from infinite (free flight) to a height-to-chord clearance of 0.067. The freestream Mach number at which flow compressibility significantly affects the predicted aerodynamic coefficients was identified to be as low as 0.15. Beyond this point, as the compressible flow conditions around the wing result in changed pressure distribution and separation behavior, treating the flow as incompressible becomes inappropriate and leads to consistent underprediction of lift and drag. The influence on primary vortex behavior of density changes around the wing was found to be relatively inconsequential even at the higher end of the Mach scale investigated. By a freestream Mach number of 0.4 and at low clearances, local supersonic flow regions were established close to the suction peak of the lower wing surface in compressible simulations; the formation of a normal shock wave between the wing and the ground was shown to result in significant increases in separation and therefore overall drag, as well as a distinct loss of downforce. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JFEGA400013 [...]