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Experimental investigation of the acoustic role of the output duct in the discharge of a high pressure flow through diaphragms and perforated plates

Laffay, Paul and Jacob, Marc C. and Moreau, Stéphane and Regnard, Josselin Experimental investigation of the acoustic role of the output duct in the discharge of a high pressure flow through diaphragms and perforated plates. (2018) In: 2018 AIAA/CEAS Aeroacoustics Conference, AIAA AVIATION Forum, 25 June 2018 - 29 June 2018 (Atlanta, United States).

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Official URL: https://doi.org/10.2514/6.2018-3606

Abstract

This work presents the second step of an experimental study of the noise radiated by a complete flow discharge/control system allowing to expand or evacuate a flow under pressure by passing though diaphragms or perforated plates. The first step of the study, focused on the study of the noise radiated by the passage of the flow through the perforated plates/diaphragms, allowed to identify the presence of three distinct radiation sources: a broadband noise associated with the mixing of the flow at the exit of the perforations and which is strongly linked to the geometry, a shock noise (screech and broadband shock associated noise) associated with the presence of shock cells in the ow for supersonic regimes and a tonal noise associated with a feedback loop and appearing for low subsonic operating points. By adding a duct downstream to the discharge zone to be closer to real geometries found in industry, the broadband noise is strongly modified by the appearance of strong acoustic resonances in the outlet duct. These resonances are moreover strongly affected by the operating point which drives the flow intensity in the duct. A simple analytical model is proposed in order to quickly predict the different acoustic modificationscations induced by the outlet duct in case of simple geometries. Finally, the shock noise, as observed without duct, is totally suppressed but is replaced by "base-pressure oscillation" responsible for strong low frequency tones for diaphragms and perforated plates with large cross-sections.

Item Type:Conference or Workshop Item (Paper)
Audience (conference):International conference proceedings
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE)
Other partners > SAFRAN (FRANCE)
Other partners > Université de Lyon - UDL (FRANCE)
Laboratory name:
Funders:
Agence Nationale de la Recherche (ANR) - Labex Celya Investissement d'Avenir (ANR-10- LABX-0060/ANR-11-IDEX-0007) - Agence Nationale de la Recherche (ANR) - Chaire Industrielle Adopsys - (ANR-13-CHIN-0001-01) - Safran Aircraft Engines - Chaire Industrielle Adopsys
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Deposited By: Marc C. JACOB
Deposited On:26 Sep 2018 14:50

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