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The Scaling of Broadband Shock-Associated Noise with Increasing TemperatureA physical explanation for the saturation of broadband shock-associated noise (BBSAN) intensity with increasing jet stagnation temperature has eluded investigators. An explanation is proposed for this phenomenon with the use of an acoustic analogy. To isolate the relevant physics, the scaling of BBSAN peak intensity level at the sideline observer location is examined. The equivalent source within the framework of an acoustic analogy for BBSAN is based on local field quantities at shock wave shear layer interactions. The equivalent source combined with accurate calculations of the propagation of sound through the jet shear layer, using an adjoint vector Green's function solver of the linearized Euler equations, allows for predictions that retain the scaling with respect to stagnation pressure and allows for saturation of BBSAN with increasing stagnation temperature. The sources and vector Green's function have arguments involving the steady Reynolds- Averaged Navier-Stokes solution of the jet. It is proposed that saturation of BBSAN with increasing jet temperature occurs due to a balance between the amplication of the sound propagation through the shear layer and the source term scaling.
Document ID
20150013946
Acquisition Source
Langley Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Miller, Steven A. E.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
July 22, 2015
Publication Date
January 22, 2013
Subject Category
Acoustics
Report/Patent Number
NF1676L-15961
Funding Number(s)
WBS: WBS 475122.02.07.05.01
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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