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Role of Coherent Structures in Turbulent Premixed Flame Acoustics

Brouzet, D. and Haghiri, A. and Talei, M. and Brear, M. J. and Schmidt, O. T. and Rigas, G. and Colonius, T. (2020) Role of Coherent Structures in Turbulent Premixed Flame Acoustics. AIAA Journal, 58 (6). pp. 2635-2642. ISSN 0001-1452. https://resolver.caltech.edu/CaltechAUTHORS:20200415-094204836

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Abstract

Spectral proper orthogonal decomposition (SPOD) is applied to direct numerical simulation datasets of a lean and a stoichiometric methane–air turbulent premixed jet flame. SPOD is used to extract the coherent structures that correlate with the radiated sound by using an inner product based on a linearized disturbance energy. Two types of structures are prominent in the data. The first type arises in the jet’s shear layer and is linked to the Kelvin–Helmholtz instability, which is an important mechanism of sound generation in nonreacting jets. These structures produce sound through deformation of the flame front in the shear layer. They contain most of the acoustic energy and are dominant at Strouhal numbers (defined based on the jet’s diameter and the inlet mean velocity) less than unity. The second type of structures is found near the jet centerline, where large fluctuations of the flame surface are observed. The structures are linked to small nonlinear flame dynamics and to the Orr mechanism. They travel at a speed close to the inlet mean velocity and are important at higher Strouhal numbers. Regardless of their energy content, both types of structures have important contributions to the broadband nature of combustion noise.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.2514/1.j058480DOIArticle
https://arc.aiaa.org/doi/suppl/10.2514/1.J058480PublisherSupplementary Materials
ORCID:
AuthorORCID
Rigas, G.0000-0001-6692-6437
Colonius, T.0000-0003-0326-3909
Additional Information:© 2020 by the American Institute of Aeronautics and Astronautics, Inc. Received 18 March 2019; revision received 14 November 2019; accepted for publication 9 February 2020; published online 15 April 2020. This work was supported by the Australian Research Council (ARC; grants DP120101830 and DE180100416) and the University of Melbourne through a Melbourne International Research Scholarship and a Melbourne International Fee Remission Scholarship. The research benefited from computational resources provided through the National Computational Merit Allocation Scheme, supported by the Australian Government. The computational facilities supporting this project included the Australian National Computational Infrastructure (NCI) and the Pawsey Supercomputing Center.
Funders:
Funding AgencyGrant Number
Australian Research CouncilDP120101830
Australian Research CouncilDE180100416
University of MelbourneUNSPECIFIED
Issue or Number:6
Record Number:CaltechAUTHORS:20200415-094204836
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200415-094204836
Official Citation:Role of Coherent Structures in Turbulent Premixed Flame Acoustics. D. Brouzet, A. Haghiri, M Talei, M. J. Brear, O. T. Schmidt, G. Rigas, and T. Colonius. AIAA Journal 2020 58:6, 2635-2642; doi: 10.2514/1.j058480
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:102551
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:15 Apr 2020 16:48
Last Modified:02 Jun 2020 16:44

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