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Inlet contour and flow effects on radiationAn experimental investigation of sound radiation from inlets with different contours with and without flow is being conducted to study the possibility of reducing noise radiated by aircraft engines. For each inlet configuration, complex directivity patterns and complex pressure reflection coefficients are measured as a function of a single space-time structure of the wave (up to a frequency of 4000Hz and an azimuthal wave number 6) and of flow velocity (up to Mach number 0.4) in a cylindrical duct located downstream the inlet. Experimental results of radiation from an unflanged duct are compared with theory. Effect of inlet contour and flow are deduced by comparing respectively unflanged duct and bellmouth measurements and, no flow and flow measurements with the bellmouth. Results are presented which indicate that the contour effect is significant near the cut-on frequency of a mode and emphasize the necessity for taking into account the inlet geometry in a radiation prediction. These results show also that internal flow has a weak effect on the amplitude of the directivity pattern
Document ID
19800051772
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Ville, J. M.
(Compiegne, Universite de Technologie, Compiegne, France)
Silcox, R. J.
(NASA Langley Research Center Hampton, Va., United States)
Date Acquired
August 10, 2013
Publication Date
June 1, 1980
Subject Category
Acoustics
Report/Patent Number
AIAA PAPER 80-0966
Meeting Information
Meeting: Aeroacoustics Conference
Location: Hartford, CT
Start Date: June 4, 1980
End Date: June 6, 1980
Sponsors: American Institute of Aeronautics and Astronautics
Accession Number
80A35942
Distribution Limits
Public
Copyright
Other

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