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Effect of Nozzle Geometry on Jet Noise Reduction Using Fan Flow Deflectors

Papamoschou, Dimitri and Shupe, Rebecca S. (2006) Effect of Nozzle Geometry on Jet Noise Reduction Using Fan Flow Deflectors. In: 12th AIAA/CEAS Aeroacoustics Conference (27th AIAA Aeroacoustics Conference), 8-10 May, 2006, Cambridge, MA.

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We examine the effect of baseline nozzle shape on the ability of fan flow deflectors to reduce downward-emitted turbulent mixing noise of coaxial jets simulating the exhaust condition of a turbofan engine. Several deflector concepts were tested on a nozzle with parallel exit flow lines and a nozzle with convergent flow lines. In every comparison the nozzle with convergent flow lines produced superior acoustic benefit. Mean flow measurements indicate that the convergent lines help the deflectors reduce velocity gradients uniformly on the underside of the jet. In contrast, the parallel flow lines contributed to reduction in gradients in a narrow direction, with occasional increase of gradients in other directions that influence emission towards the ground.

Item Type:Conference or Workshop Item (Paper)
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Additional Information:Copyright © 2006 by D. Papamoschou. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. The support by NASA Glenn Research Center is gratefully acknowledged (Grant NAG-3-2345 monitored by Dr. Khairul B. Zaman and Dr. James Bridges. The method and system of noise suppression via deflection of the bypass and/or core streams is proprietary to the University of California. U.S. Patent Pending.
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NASA Glenn Research CenterNAG-3-2345
Record Number:CaltechAUTHORS:20091113-211334547
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16707
Deposited By: Rebecca Shupe
Deposited On:16 Nov 2009 23:26
Last Modified:03 Oct 2019 01:15

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