Reba, Ramons and Narayanan, Satish and Colonius, Tim (2010) Wave-packet models for large-scale mixing noise. International Journal of Aeroacoustics, 9 (4-5). pp. 533-557. ISSN 1475-472X http://resolver.caltech.edu/CaltechAUTHORS:20100810-142241271
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A wave-packet Ansatz is used to model jet noise generation by large-scale turbulence. In this approach, an equivalent source is defined based on the two-point space-time correlation of hydrodynamic pressure on a conical surface surrounding the jet plume. The surface is sufficiently near the turbulent flow region to be dominated by non-propagating hydrodynamic signatures of large-scale turbulent structures, yet sufficiently far that linear behavior can be assumed in extending the near-field pressure to the acoustic field. In the present study, a 78-microphone array was used to measure hydrodynamic pressure on the conical surface in order to identify parameters for the model and to validate the approach. Six microphones were distributed in the azimuthal direction at each of 13 axial locations spanning the first 8 jet diameters, allowing decomposition of azimuthal modes m = 0 and m = 1. We show that a source model based on a Gaussian correlation function provides a consistently good representation of the noise source attributed to large-scale structures. The results provide evidence that large-scale wave-like structures, known to dominate aft radiation at supersonic phase speeds, are also relevant at subsonic speeds.
|Additional Information:||© 2010 Multi-Science Publishing. Submitted April 16, 2009; Revised December 17, 2009; Accepted January 12, 2010. The authors are indebted to Drs. J. Bridges and S.-S. Lee for generously sharing their data and for fruitful discussions. Tim Colonius gratefully acknowledges the support of a grant from the Aeroacoustics Research Consortium (AARC) of the Ohio Aerospace Institute. We also wish to thank Dr. R. Schlinker for technical discussions and support.|
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|Deposited By:||Tony Diaz|
|Deposited On:||10 Aug 2010 21:31|
|Last Modified:||26 Dec 2012 12:18|
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