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Contribution à l'étude des phénomènes aéroacoustiques se développant dans la baignoire et autour des pantographes du TGV. Approches expérimentale et numérique des écoulements affleurant une cavité et interactions non-linéaires de sillage entre deux cylindres

Abstract : This study is performed under contract with SNCF and DEUTSCH BAHN as a part of the German-French Cooperation DEUFRAKO K2 which deals with high-speed train noise. First, a shallow rectangular cavity is located in an anechoïc wind-tunnel. Parietal flow visualization and anemometry measurements show the flow to reattach on the cavity bottom wall and to separate again at the downstream edge. This phenomenon is at the origin of strong wall pressure fluctuations measured with microphones grazing wall mounted. 3D intensimetry indicates the principal sound sources to stand near the downstream edge of the cavity. The acoustical study show the narrow band characteristic of the acoustic radiation and that it does not appear any aerodynamic or acoustic oscillation. A realistic 1/7e scale mock-up of the recess was then designed and placed in a low-subsonic wind-tunnel. Parietal flow visualizations show a very complex 3D flow structure. Anemometry measurements indicate the upstream shear layer to reattach early on the recess bottom wall and a strong vertical jet standing at the downstream edge. Wall pressure coefficients (microphones) remain quasi-uniform in all the recess. The spectral analysis reveals two regions with mode resonances and the pantograph peak (STROUHAL). The pantograph influences are simulated via their modelisation with two circular cylinders, whose spacing and incidence are variable, placed in the anechoïc wind-tunnel. The experiments reveal strong aeroacoustic couplings (feedback) evolving with these two parameters. The spectral and bispectral analysis of the far-field acoustic radiation (measured with microphone) associated with visualizations and velocity fields measured with PIV contribute to the interpretation of these phenomena. The experiments of each study are compared with numerical simulations.
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https://tel.archives-ouvertes.fr/tel-00006437
Contributor : Christophe Noger <>
Submitted on : Sunday, July 11, 2004 - 9:26:35 PM
Last modification on : Wednesday, May 15, 2019 - 10:34:02 AM
Long-term archiving on: : Friday, April 2, 2010 - 8:02:28 PM

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  • HAL Id : tel-00006437, version 1

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Christophe Noger. Contribution à l'étude des phénomènes aéroacoustiques se développant dans la baignoire et autour des pantographes du TGV. Approches expérimentale et numérique des écoulements affleurant une cavité et interactions non-linéaires de sillage entre deux cylindres. Acoustique [physics.class-ph]. Université de Poitiers, 1999. Français. ⟨tel-00006437⟩

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