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Applications of velocity potential function to acoustic duct propagation and radiation from inlets using finite element theoryA finite element velocity potential program has been developed to study acoustic wave propagation in complex geometries. For irrotational flows, relatively low sound frequencies, and plane wave input, the finite element solutions show significant effects of inlet curvature and flow gradients on the attenuation of a given acoustic liner in a realistic variable area turbofan inlet. In addition, as shown in the paper, the velocity potential approach can not be used to estimate the effects of rotational flow on acoustic propagation since the potential acoustic disturbances propagate at the speed of the media in sheared flow. Approaches are discussed that are being considered for extending the finite element solution to include the far field as well as the internal portion of the duct. A new matrix partitioning approach is presented that can be incorporated in previously developed programs to allow the finite element calculation to be marched into the far field. The partitioning approach provides a large reduction in computer storage and running times.
Document ID
19790042876
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Baumeister, K. J.
(NASA Lewis Research Center Cleveland, Ohio, United States)
Majjigi, R. K.
(General Electric Co. Cincinnati, Ohio, United States)
Date Acquired
August 9, 2013
Publication Date
March 1, 1979
Subject Category
Acoustics
Report/Patent Number
AIAA PAPER 79-0680
Meeting Information
Meeting: American Institute of Aeronautics and Astronautics, Aeroacoustics Conference
Location: Seattle, WA
Start Date: March 12, 1979
End Date: March 14, 1979
Sponsors: American Institute of Aeronautics and Astronautics
Accession Number
79A26889
Distribution Limits
Public
Copyright
Other

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