Laboratoire de Mécanique des Fluides et d'Acoustique - UMR 5509

LMFA - UMR 5509
Laboratoire de Mécanique des Fluides et d’Acoustique

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École Centrale de Lyon

Sujet de thèse de doctorat - PhD Thesis proposal (2021)

Sujet de thèse de doctorat - PhD Thesis proposal (2021)

Non-linear acoustic behaviors in a lined flow duct

Reducing the noise radiated by a duct in the presence of flow is a problem encountered in many industrial applications. This is for example the case of jet engine nacelles, exhaust pipes, ventilation systems, .... In some cases, high sound pressure levels are generated in the duct (up to 170 dB in nacelles). The main objective of this thesis is to
define effective control strategies to reduce the noise in this context. Metallic liners (e.g. perforated sheets on honeycomb) are usually installed on the wall, but other types of absorbers are being studied, such as periodic media, metamaterials able to block the transmission in a specific frequency range. These passive structures can also be
combined with active means to increase their efficiency.

Sujet détaillé

Thesis direction :
Marie-Annick Galland, LMFA, ECL,
Didier Dragna, LMFA, ECL,
Emmanuel Gourdon, LTDS, ENTPE,