Parabolized stability equation models for predicting large-scale mixing noise of turbulent round jets

Rodriguez, D and Samanta, A and Cavalieri, AVG and Colonius, T and Jordan, P (2011) Parabolized stability equation models for predicting large-scale mixing noise of turbulent round jets. In: 17th AIAA/CEAS Aeroacoustics Conference (32nd AIAA Aeroacoustics Conference), 05 June 2011 - 08 June 2011, California.

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Abstract

Parabolized stability equation (PSE) models are being deve loped to predict the evolu-tion of low-frequency, large-scale wavepacket structures and their radiated sound in high-speed turbulent round jets. Linear PSE wavepacket models were previously shown to be in reasonably good agreement with the amplitude envelope and phase measured using a microphone array placed just outside the jet shear layer. 1,2 Here we show they also in very good agreement with hot-wire measurements at the jet center line in the potential core,for a different set of experiments. 3 When used as a model source for acoustic analogy, the predicted far field noise radiation is in reasonably good agreement with microphone measurements for aft angles where contributions from large -scale structures dominate the acoustic field. Nonlinear PSE is then employed in order to determine the relative impor-tance of the mode interactions on the wavepackets. A series of nonlinear computations with randomized initial conditions are use in order to obtain bounds for the evolution of the modes in the natural turbulent jet flow. It was found that n onlinearity has a very limited impact on the evolution of the wavepackets for St≥0. 3. Finally, the nonlinear mechanism for the generation of a low-frequency mode as the difference-frequency mode 4,5 of two forced frequencies is investigated in the scope of the high Reynolds number jets considered in this paper.

Item Type:	Conference Proceedings
Publisher:	American Institute of Aeronautics and Astronautics
Additional Information:	Copyright of this article belongs to American Institute of Aeronautics and Astronautics.
Department/Centre:	Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering)
Date Deposited:	02 May 2013 10:37
Last Modified:	02 May 2013 10:37
URI:	http://eprints.iisc.ac.in/id/eprint/46289

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