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Wavepacket eduction in turbulent jets based on eigenmode decomposition of PIV data

Rodríguez, Daniel and Cavalieri, André V. G. and Colonius, Tim and Jordan, Peter (2013) Wavepacket eduction in turbulent jets based on eigenmode decomposition of PIV data. In: 19th AIAA/CEAS Aeroacoustics Conference, 27-29 May 2013, Berlin, Germany.

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The dynamics of large scale structures in unforced turbulent jets at subsonic speeds have been related to the generation of the peak noise radiated the aft direction. The utility of instability wavepackets computed by linear stability theory or parabolised stability equations (PSE) have been demonstrated for the modeling of the near-field pressure fluctuations associated with the coherent structures. In this paper, we investigate whether the velocity field corresponding to the wavepackets also represents adequately that of the coherent structures. Previous research showed remarkable agreement in the velocity field up to the end of the potential core, but the agreement is lost gradually downstream. Locally-parallel linear stability theory (LST) of jet velocity profiles is revisited to further study the evolution of the wavepackets and the manner in which PSE models them. An adjoint-based eigenmode decomposition technique is used to project cross-sectional velocity profiles measured using time-resolved particle image velocimetry (PIV) on the Kelvin-Helmholtz eigenmode responsible for the wavepacket amplification. The instability wave thus extracted is then compared, both in amplification and shape, to the PSE wavepacket and to the dominant coherent structures obtained from the proper orthogonal decomposition of the PIV measurements. The comparisons between PSE models and POD-filtered fluctuations define three spatial regions along the streamwise direction that are explained in terms of changes in the LST eigenspectrum.

Item Type:Conference or Workshop Item (Paper)
Related URLs:
URLURL TypeDescription Paper Paper
Cavalieri, André V. G.0000-0003-4283-0232
Colonius, Tim0000-0003-0326-3909
Jordan, Peter0000-0001-8576-5587
Additional Information:© 2013 American Institute of Aeronautics and Astronautics. Published Online: 24 May 2013. We thank Drs. Kristjan Gudmundsson, Arnab Samanta and Aniruddha Sinha for their contributions on the development of the PSE code and Carine Fourment-Cazenave, Patrick Braud and Dr. Joël Delville for their work during the experiments. The work of D. Rodríguez was supported by the EU Marie Curie COFUND program.
Funding AgencyGrant Number
Marie Curie FellowshipUNSPECIFIED
Subject Keywords:Aeroacoustics
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Other Numbering System NameOther Numbering System ID
AIAA Paper2013-2084
Record Number:CaltechAUTHORS:20190712-112323422
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:97127
Deposited By: Melissa Ray
Deposited On:16 Jul 2019 16:44
Last Modified:16 Nov 2021 17:26

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