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The Acoustic Analogy and Alternative Theories for Jet Noise PredictionThis paper describes several methods for the prediction of jet noise. All but one of the noise prediction schemes are based on Lighthill's or Lilley's acoustic analogy while the other is the jet noise generation model recently proposed by Tam and Auriault. In all the approaches some assumptions must be made concerning the statistical properties of the turbulent sources. In each case the characteristic scales of the turbulence are obtained from a solution of the Reynolds-averaged Navier Stokes equation using a k-epsilon turbulence model. It is shown that, for the same level of empiricism, Tam and Auriault's model yields better agreement with experimental noise measurements than the acoustic analogy. It is then shown that this result is not because of some fundamental flaw in the acoustic analogy approach: but, is associated with the assumptions made in the approximation of the turbulent source statistics. If consistent assumptions are made, both the acoustic analogy and Tam and Auriault's model yield identical noise predictions. The paper concludes with a proposal for an acoustic analogy that provides a clearer identification of the equivalent source mechanisms and a discussion of noise prediction issues that remain to be resolved.
Document ID
20050041979
Acquisition Source
Langley Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Morris, Philip J.
(NASA Langley Research Center Hampton, VA, United States)
Farassat, F.
(NASA Langley Research Center Hampton, VA, United States)
Morris, Philip J.
(Pennsylvania State Univ. University Park, PA, United States)
Date Acquired
September 7, 2013
Publication Date
January 1, 2002
Publication Information
Publication: AIAA Journal
Volume: 40
Issue: 4
Subject Category
Aircraft Design, Testing And Performance
Distribution Limits
Public
Copyright
Public Use Permitted.
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