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Descripción
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| Instability analyses of incompressible ow through two intakes, both having realistic cross-sectional pro- les have been performed. Without reference to concrete applications, representative duct geometries, inspired from motor racing and ghter jets has been selected. The projections on the plane normal to the streamwise ow direction normal to the plane of the intake, of two such duct geometries are depicted in gure 1; the parametric de nition of these ducts is detailed in what follows. In order for the analysis to proceed two key assumptions are made. First, ow is taken to be homogeneous along the streamwise spatial direction; in section IV a suggestion is put forward on how this approximation may be relaxed. Second, ow is taken to be laminar and incompressible, driven by a constant pressure gradient along the streamwise spatial direction; section IV also discusses potential extensions of the present analysis toward compressible and turbulent ows. Linear instability of complex ows may be analyzed by numerical solutions of partial-derivative-based eigenvalue problems (EVP); the concepts are respectively referred to as BiGlobal or TriGlobal instability, depending on whether two- or three spatial directions are resolved simultaneously. Numerical solutions of the BiGlobal EVP in ows of engineering signi cance, have been reviewed relatively recently.1 Linear instability in duct ows of simple cross-sections has been addressed by Tatsumi & Yoshimura2 and Kerswell & Davey,3 amongst others. The novelty of the present work relies in the generalization of the simple numerical tools utilized in the early analyses of duct ows, in order to study instability in ows through arbitrarily-shaped duct con gurations of practical signi cance. To complete the study of these intakes the adjoint problem has been also solved and the receptivity and sensitivity elds are obtained, the interested reader is referred to the article of Giannetti and Luchini4 and the book of Schmid and Henningson5 for the theoretical background. From a numerical point of view, use is made of recent advances in the accurate solution of BiGlobal eigenvalue problems in ows over complex geometries;6{8 presently, a spectral/hp element method9 is employed. From a physical point of view, a-posteriori evaluation of the results obtained examines whether the assumption of streamwise homogeneity is justi able, by comparing the wavelength of the leading eigenmodes with the characteristic streamwise length in each intake geometry. | |
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Internacional
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Si |
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Nombre congreso
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4th Flow Control Conference, Seattle, WA, June 23-26, 2008 |
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Tipo de participación
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960 |
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Lugar del congreso
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Seattle, WA |
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Revisores
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Si |
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ISBN o ISSN
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9781605603698 |
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DOI
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Fecha inicio congreso
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23/06/2009 |
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Fecha fin congreso
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26/06/2009 |
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Desde la página
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344 |
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Hasta la página
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367 |
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Título de las actas
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4th AIAA Flow Control Conference 2008 |