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Supersonic Jet Noise from Round and Chevron Nozzles: Experimental Studies

Schlinker, R. H. and Simonich, J. C. and Shannon, D. W. and Reba, R. A. and Colonius, T. and Gudmundsson, K. and Ladeinde, F. (2009) Supersonic Jet Noise from Round and Chevron Nozzles: Experimental Studies. In: 15th AIAA/CEAS Aeroacoustics Conference (30th AIAA Aeroacoustics Conference), 11-13 May 2009, Miami, FL.

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High speed exhaust noise reduction continues to be a research challenge for supersonic cruise business jets as well as for current and future tactical military aircraft. Significant noise reduction may be possible from advanced concepts for controlling instability generated large-scale turbulence structures in the jet shear layer, generally accepted to be the source of aft-angle noise. In response to this opportunity, our team is focused on experimental diagnostic studies and unique instability modeling suited for identifying control strategies to reduce large scale structure noise. The current paper benchmarks the jet noise from supersonic nozzles designed to provide the supporting experimental data and validation of the modeling. Laboratory scale jet noise experiments are presented for a Mach number of Mj = 1.5 with stagnation temperature ratios ranging from Tr = 0.75 to 2. The baseline configuration is represented by a round converging-diverging (CD) ideal expansion nozzle. A round CD nozzle with chevrons is included as the first of several planned non-circular geometries directed at demonstrating the impact on large scale structure noise and validating noise prediction methods for geometries of future technological interest. Overexpanded and underexpanded conditions were tested on both nozzle configurations. The resulting data base provides an opportunity to benchmark the statistical characteristics of round and chevron nozzle data. The current paper examines far field spectra, directivity patterns, and overall sound pressure level dependence comparing observed characteristics with the fine scale turbulence noise and large-scale turbulence structure noise characteristics identified by Tam. In addition, the paper probes the effect of chevrons on the developing flow field and suppression of screech tones. Measurements are also reported from a far-field narrow aperture phased array system used to map the acoustic source distribution on the jet axis. The dominant source region, situated between the end of the potential core and the sonic point, was found to agree with the peak amplitude location of the jet near field wavepackets measured using a unique near field array. This observation supports the cause-effect link between large-scale turbulence structures in the shear layer and their dominant contribution to aft radiated far field noise.

Item Type:Conference or Workshop Item (Paper)
Related URLs:
URLURL TypeDescription Paper Paper
Colonius, T.0000-0003-0326-3909
Additional Information:© 2009 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. Published Online: 4 Nov 2012. The authors gratefully acknowledge NAVAIR and TTC Technologies Inc. for supporting this effort.
Funding AgencyGrant Number
Naval Air Systems Command (NAVAIR)UNSPECIFIED
Subject Keywords:Aeroacoustics
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Other Numbering System NameOther Numbering System ID
AIAA Paper2009-3257
Record Number:CaltechAUTHORS:20190717-102320667
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:97218
Deposited By: Melissa Ray
Deposited On:18 Jul 2019 22:05
Last Modified:16 Nov 2021 17:29

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