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Investigating the Feedback Path in a Jet-Surface Resonant InteractionA resonant interaction between an 8:1 aspect ratio rectangular jet and flat-plates, placed parallel to the jet, is studied experimentally. For certain locations of the plate relative to the jet, the resonance takes place with a loud accompanying tone. The sound pressure level spectra are often marked by multiple peaks. The frequencies of the spectral peaks are studied as a function of the streamwise length of the plate, its relative location to the jet as well as the jet Mach number. It is demonstrated that the tones are not due to a simple feedback between the plate's trailing edge and the nozzle's exit; the leading edge of the plate also comes into play in the frequency selection. With parametric variation, it is found that there is an order in the most energetic spectral peaks; their frequencies cluster in distinct bands. The 'fundamental', i.e., the lowest frequency band is explained by an acoustic feedback involving diffraction at the plate's leading edge.
Document ID
20150015571
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
Zaman, K. B. M. Q.
(NASA Glenn Research Center Cleveland, OH United States)
Fagan, A. F.
(NASA Glenn Research Center Cleveland, OH United States)
Bridges, J. E.
(NASA Glenn Research Center Cleveland, OH United States)
Brown, C. A.
(NASA Glenn Research Center Cleveland, OH United States)
Date Acquired
August 7, 2015
Publication Date
June 22, 2015
Subject Category
Acoustics
Report/Patent Number
GRC-E-DAA-TN23098
Meeting Information
Meeting: AIAA/CEAS Aeroacoustics Conference
Location: Dallas, TX
Country: United States
Start Date: June 22, 2015
End Date: June 26, 2015
Sponsors: Council of European Aerospace Societies, American Inst. of Aeronautics and Astronautics
Funding Number(s)
WBS: WBS 475122.02.03.05.03
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Keywords
Resonance
Jet Noise
Turbulence
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