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On the Noise Generated by Shear-Layer Instabilities in Turbulent Jets

Bertolotti, Fabio P. and Colonius, Tim (2003) On the Noise Generated by Shear-Layer Instabilities in Turbulent Jets. In: 41st Aerospace Sciences Meeting and Exhibit, 6-9 January 2003, Reno, NV. https://resolver.caltech.edu/CaltechAUTHORS:20190718-165125289

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Abstract

Solutions to the linearized equations of motion are used to study sound radiation by convected disturbances in the jet core. The spectrum of eigenmodes reveals the presence of modes that represent convected vortical and entropic motions in the potential core of the jet. We investigate the near-field acoustics produced by these core modes using the Parabolozied Stability Equations. At the conditions of commercial jet engines during take-off, the core modes radiate sound effectively along Mach lines due to the jet centerline velocity being supersonic relative to the fee-stream speed of sound. Summing three of these modes to create two distinct disturbances - one that is velocity dominated, and another that is entropy dominated - one observes that entropy variations radiate sound more effectively than vortical variations. The results yield a first insight into the impact of large-scale mixing inhomogeneities on the acoustic field. Such disturbances are created by devices in the jet engine itself, such as flow mixers, turbine exit vanes, and combustion-chamber (i.e. pattern factors).


Item Type:Conference or Workshop Item (Paper)
Related URLs:
URLURL TypeDescription
https://doi.org/10.2514/6.2003-1062DOIConference Paper
https://arc.aiaa.org/doi/10.2514/6.2003-1062PublisherConference Paper
ORCID:
AuthorORCID
Colonius, Tim0000-0003-0326-3909
Alternate Title:On the Noise Generated by Convected Structures in a Mach 0.9, Hot, Turbulent Jet
Additional Information:© 2003 by United Technologies Corporation. Published by the American Institute of Aeronautics and Astronautics, Inc. with permission. Published Online: 11 Nov 2012.
Subject Keywords:Aerospace Systems, Operations and Life Cycle
Other Numbering System:
Other Numbering System NameOther Numbering System ID
AIAA Paper2003-1062
Record Number:CaltechAUTHORS:20190718-165125289
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20190718-165125289
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:97248
Collection:CaltechAUTHORS
Deposited By: Melissa Ray
Deposited On:22 Jul 2019 21:02
Last Modified:03 Oct 2019 21:29

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