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Parabolized stability equation models in turbulent supersonic jets

Rodríguez, Daniel and Sinha, Aniruddha and Brès, Guillaume A. and Colonius, Tim (2012) Parabolized stability equation models in turbulent supersonic jets. In: 18th AIAA/CEAS Aeroacoustics Conference (33rd AIAA Aeroacoustics Conference), 4-6 June 2012, Colorado Springs, CO.

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The peak noise radiation in the aft direction of high-speed, turbulent jets has been linked to the dynamics of the large-scale structures. We use the parabolized stability equations (PSE) to model these structures as wavepackets associated with instability of the turbulent mean flow. Our past work has demonstrated the utility of these models for subsonic jets; in the present work we extend these methods to supersonic jets. A large eddy simulation database corresponding to an unheated, ideally-expanded Mach 1.5 jet with Reynolds number of 300,000 is employed to extract the necessary input for the PSE (the mean flow and initial conditions) and also to perform comparisons and validations of the computed wavepackets. By contrast with subsonic jets, when the jet exit velocity is supersonic with respect to the ambient speed of sound, linear stability theory predicts that multiple instability modes, related to resonance of pressure waves within the potential core, can be present in addition to the inflectional instability. The possible coexistence of different instability mechanisms, the determination of adequate inlet conditions, and their effect on the wavepackets computed are investigated here. We compare the wavepackets predicted by PSE with fluctuations extracted from the LES data. When performing comparisons, filtering techniques need to be employed in order to extract the coherent, low frequency structures associated with wavepackets. Largescale fluctuations educed using cross-correlation techniques, such as the proper orthogonal decomposition, are shown to compare reasonably well with the PSE wavepackets, but by contrast with subsonic jets, it appears that several POD modes are required to represent the PSE-predicted wavepacket.

Item Type:Conference or Workshop Item (Paper)
Related URLs:
URLURL TypeDescription Paper Paper
Sinha, Aniruddha0000-0002-7122-3549
Brès, Guillaume A.0000-0003-2507-8659
Colonius, Tim0000-0003-0326-3909
Additional Information:© 2012 American Institute of Aeronautics and Astronautics. Published Online: 11 Nov 2012. This work was supported by NAVAIR through an STTR grant N68335-11-C-0026 to Cascade Technologies, Inc. and by ONR Grant N00014-11-1-0753. The authors would like to thank Dr. Joseph W. Nichols and Prof. Sanjiva K. Lele, of Stanford University, for their contributions to the LES efforts and their inputs on global modes. The LES calculations were carried out on CRAY XE6 machines at DoD supercomputer facilities in ERDC and AFRL.
Funding AgencyGrant Number
Naval Air Systems Command (NAVAIR)N68335-11-C-0026
Office of Naval Research (ONR)N00014-11-1-0753
Subject Keywords:Aeroacoustics
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Other Numbering System NameOther Numbering System ID
AIAA Paper2012-2117
Record Number:CaltechAUTHORS:20190712-112323257
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:97125
Deposited By: Melissa Ray
Deposited On:15 Jul 2019 22:49
Last Modified:16 Nov 2021 17:26

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