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Wind tunnel noise reduction at Mach 5 with a rod-wall sound shieldA method of shielding a wind-tunnel model from noise radiated by the tunnel-wall boundary layer has been developed and tested at the Langley Research Center. The shield consists of a rectangular array of longitudinal rods with boundary-layer suction through gaps between the rods. Tests were conducted at Mach 5 over a unit Reynolds number range of 1.0-3.5 x 10 to the 7th/m. Hot-wire measurements indicated the freestream noise, expressed in terms of the rms pressure fluctuations normalized by the mean pressure, was reduced from about 1.4 percent just upstream of the shielded region of a minimum level of about 0.4 percent in the forward portion of the shielded flow.
Document ID
19830047734
Document Type
Reprint (Version printed in journal)
Authors
Creel, T. R. (NASA Langley Research Center Hampton, VA, United States)
Beckwith, I. E. (NASA Langley Research Center High-Speed Aerodynamics Div., Hampton, VA, United States)
Date Acquired
August 11, 2013
Publication Date
May 1, 1983
Publication Information
ISSN: 0001-1452
Subject Category
RESEARCH AND SUPPORT FACILITIES (AIR)
Report/Patent Number
AIAA PAPER 82-0570
Distribution Limits
Public
Copyright
Other