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The sound of moving bodiesThe importance of the quadrupole source term in the Ffowcs, Williams, and Hawkings (FWH) equation was addressed. The quadrupole source contains fundamental components of the complete fluid mechanics problem, which are ignored only at the risk of error. The results made it clear that any application of the acoustic analogy should begin with all of the source terms in the FWH theory. The direct calculation of the acoustic field as part of the complete unsteady fluid mechanics problem using CFD is considered. It was shown that aeroelastic calculation can indeed be made with CFD codes. The results indicate that the acoustic field is the most susceptible component of the computation to numerical error. Therefore, the ability to measure the damping of acoustic waves is absolutely essential both to develop acoustic computations. Essential groundwork for a new approach to the problem of sound generation by moving bodies is presented. This new computational acoustic approach holds the promise of solving many problems hitherto pushed aside.
Document ID
19910012514
Acquisition Source
Legacy CDMS
Document Type
Thesis/Dissertation
Authors
Brentner, Kenneth Steven (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
September 6, 2013
Publication Date
December 1, 1990
Subject Category
Acoustics
Report/Patent Number
NAS 1.15:103342
NASA-TM-103342
Accession Number
91N21827
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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