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Active Control of Noise from Hot Supersonic Jets

Sinha, Aniruddha and Towne, Aaron and Colonius, Tim and Schlinker, Robert H. and Reba, Ramons and Simonich, John C. and Shannon, Daniel W. (2018) Active Control of Noise from Hot Supersonic Jets. AIAA Journal, 56 (3). pp. 933-948. ISSN 0001-1452. http://resolver.caltech.edu/CaltechAUTHORS:20180329-105253706

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Abstract

This paper presents diagnostic experiments aimed at understanding and mitigating supersonic jet noise from the coherent wave-packet structures that are the source of peak aft-angle mixing noise. Both isothermal and heated, nearly perfectly expanded, Mach 1.5 jets were forced in the near-nozzle region with air injection generated by a spinning-valve device designed to excite the jet at frequencies approaching those of the dominant turbulent structures. Substantial reductions in the peak aft-angle radiation were achieved with steady blowing at amplitudes corresponding to 2–6% of the mass flow rate of the primary jet. The noise benefit saturated at mass flow rates above 4%, with as much as a 6 dB reduction in overall sound pressure level at aft angles. Increasing the mass flow rates yielded a monotonically increasing high-frequency noise penalty at the sideline, where noise levels in the natural jet were already 15 dB lower than the aft-angle peak, so that the penalty due to actuation was minor. Although both steady and periodic unsteady mass injections were produced by the spinning valve when it rotated, it was calibrated to hold the steady mass flow rate constant as the frequency of unsteady blowing was changed. In this way, the effect of steady and unsteady blowings on the acoustic field could be decoupled. It is shown that the noise benefit was uniquely associated with the steady component of blowing, whereas the unsteady component resulted in additive tones in the spectra. This implied linearity is consistent with theory and experiments showing that the wave-packet structures, which give rise to the dominant aft-angle radiation, evolve in the turbulent mean flowfield in a nearly linear fashion from their origin in the near-nozzle region. The interpretation of noise reduction is that the steady component of blowing spreads the mean flow more rapidly, resulting in weaker wave packets. Periodic unsteady blowing forces coherent wave packets that are largely uncorrelated from the random natural ones, which then leads to the observed additive tones.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.2514/1.J056159DOIArticle
https://arc.aiaa.org/doi/10.2514/1.J056159PublisherArticle
ORCID:
AuthorORCID
Towne, Aaron0000-0002-7315-5375
Colonius, Tim0000-0003-0326-3909
Additional Information:© 2017 by Aniruddha Sinha, Aaron Towne, Tim Colonius, Robert H. Schlinker, Ramons Reba, John C. Simonich, and Daniel W. Shannon. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. Received 15 March 2017; revision received 13 October 2017; accepted for publication 15 October 2017; published online 23 November 2017. The authors gratefully acknowledge support from the Office of Naval Research under contract N0014-11-1-0753 with Joseph Doychak and Brenda Henderson as Technical Monitors and from Naval Air Systems Command under Small Business Technology Transfer contract N68335-11-C-0026 with John Spyropoulos as Technical Monitor.
Funders:
Funding AgencyGrant Number
Office of Naval Research (ONR)N0014-11-1-0753
Naval Air Systems Command (NAVAIR)N68335-11-C-0026
Record Number:CaltechAUTHORS:20180329-105253706
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20180329-105253706
Official Citation:Aniruddha Sinha, Aaron Towne, Tim Colonius, Robert H. Schlinker, Ramons Reba, John C. Simonich, and Daniel W. Shannon. "Active Control of Noise from Hot Supersonic Jets", AIAA Journal, Vol. 56, No. 3 (2018), pp. 933-948. https://doi.org/10.2514/1.J056159
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:85492
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:29 Mar 2018 18:06
Last Modified:29 Mar 2018 18:06

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