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Tones Encountered with a Coannular Nozzle and a Method for their SuppressionWith multi-stream coannular nozzles, sometimes tones are generated that make the nozzle fail noise regulation criteria. A two-stream nozzle was studied experimentally in an attempt to identify the sources of such tones and explore remedies. With the given nozzle configuration, sharp tones occurred in a range of low jet Mach numbers (M (sub j)). The tones could be traced to a coupling of vortex shedding from the struts, that hold the nozzles and the center-body together, and various acoustic resonance modes of the ducts. A leading edge treatment of the struts is shown to suppress the vortex shedding and eliminate the tones.
Document ID
20170008108
Document Type
Presentation
Authors
Zaman, Khairul (NASA Glenn Research Center Cleveland, OH United States)
Bridges, James (NASA Glenn Research Center Cleveland, OH United States)
Fagan, Amy (NASA Glenn Research Center Cleveland, OH United States)
Miller, Chris (NASA Glenn Research Center Cleveland, OH United States)
Date Acquired
August 31, 2017
Publication Date
June 5, 2017
Subject Category
Acoustics
Numerical Analysis
Aircraft Propulsion And Power
Report/Patent Number
GRC-E-DAA-TN43247
Meeting Information
American Institute of Aeronautics and Astronautics (AIAA) Aviation Forum 2017 Aeroacoustics Conference(Denver, CO)
Funding Number(s)
WBS: WBS 110076.02.03.04.40.02
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Keywords
vortex shedding
acoustic tones
duct resonance

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