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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
Document Type
Conference Paper
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
Report/Patent Number
Meeting Information
AIAA/CEAS Aeroacoustics Conference(Dallas, TX)
Funding Number(s)
WBS: WBS 475122.
Distribution Limits
Work of the US Gov. Public Use Permitted.
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