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Wind-tunnel fan noise reduction including effects of turning vanes on noise propagationFan silencers with low-pressure drop have been designed and installed in the NASA Ames 7- by 10-Foot Wind Tunnel No. 1. The silencers are composed of an absorbent lining flush with the wind-tunnel walls upstream of the fan and an absorbent splitter in the duct downstream of the fan. An acoustical insertion loss of 4 to 12 dB was measured between 100 and 1000 Hz. High-frequency performance of the silencers was reduced by test-section noise and by corner vanes which turned the sound waves so they followed the duct axis. Sound below 1.2 kHz diffracted around the 305-mm-long vanes and impinged on acoustically absorbent corner walls. Wind-tunnel flow losses are discussed.
Document ID
19790042921
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Soderman, P. T. (NASA Ames Research Center; U.S. Army, Research and Technology Laboratories, Moffett Field Calif., United States)
Hoglund, L. E. (Beam Engineering, Inc. Sunnyvale, Calif., United States)
Date Acquired
August 9, 2013
Publication Date
March 1, 1979
Subject Category
Acoustics
Report/Patent Number
AIAA PAPER 79-0642
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
79A26934
Distribution Limits
Public
Copyright
Other

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