Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 7 of 7 for “"Grazing flow"”.
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Application of a Helmholtz resonator excited by grazing flow for manipulation of a turbulent boundary layer.
In most industrial applications involving flow the Reynolds number is typically sufficiently high such that the boundary layer is turbulent. Flow instabilities within the turbulent boundary layer can result in an excessive drag penalty which is considered to be the main parameter affecting the …
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Effect of grazing flow on structural-acoustic response of an elastic plate with sound in a duct
… of a duct in which acoustic waves propagate at grazing incidence with skin panels mounted along the duct walls. A key limitation of such facility is the absence of flow, the impact of which on the structural-acoustic response of the skin panel is still poorly understood. To shed some insight on …
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Direct numerical investigation and reduced-order modeling of 3-D honeycomb acoustic liners
… amplitude conditions, possibly with a turbulent grazing flow, are not available due to the near-liner flow complexity and diagnostic challenges. The work presented in this thesis uses direct numerical simulations (DNS) of a compressible, viscous fluid to understand the inherent fluid mechanics …
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The acoustic modelling of dissipative elements in automotive exhausts
… from the absorbent, and the effects of both grazing flow and a backing layer of porous material upon the acoustic impedance of a perforate plate are examined.Three different theoretical approaches to modelling dissipative silencers are reported, and the accuracy of each method is assessed in …
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Measurement and Analysis of Sub-Convective Pressure Fluctuations in Turbulent Boundary Layers: A Novel Methodology
Surface flow noise results from fluid-surface interactions, manifesting as surface vibrations or far-field noise. Decomposing the surface pressure field reveals distinct components, with the sub-convective component being particularly critical due to its coupling with structural modes, inducing …
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Anwendung des Lattice-Boltzmann-Verfahrens zur Berechnung strömungsakustischer Probleme
… regard to application to numerical solution of flow acoustic problems. In the first part of this study the description of sound wave propagation by common variants of the Lattice-Boltzmann-model is examined by calculation of phase velocity and effective viscosity for sound waves. Schemes with …
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Étude numérique et expérimentale du comportement non linéaire des plaques perforées en présence d’écoulement
Cette thèse étudie expérimentalement la réponse acoustique de plaques macro-perforées (pourcentage de surface ouverte (POA) jusqu’à 40% et diamètre jusqu’à 3 mm), en présence d’un écoulement rasant et soumis à des niveaux de pression acoustique (SPL) élevés jusqu’à 180 dB. Tout d’abord, une méthode …