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Acoustic Modifications of the Ames 40x80 Foot Wind Tunnel and Test Techniques for High-Speed Research Model TestingThe NFAC 40- by 80- Foot Wind Tunnel at Ames is being refurbished with a new, deep acoustic lining in the test section which will make the facility nearly anechoic over a large frequency range. The modification history, key elements, and schedule will be discussed. Design features and expected performance gains will be described. Background noise reductions will be summarized. Improvements in aeroacoustic research techniques have been developed and used recently at NFAC on several wind tunnel tests of High Speed Research models. Research on quiet inflow microphones and struts will be described. The Acoustic Survey Apparatus in the 40x80 will be illustrated. A special intensity probe was tested for source localization. Multi-channel, high speed digital data acquisition is now used for acoustics. And most important, phased microphone arrays have been developed and tested which have proven to be very powerful for source identification and increased signal-to-noise ratio. Use of these tools for the HEAT model will be illustrated. In addition, an acoustically absorbent symmetry plane was built to satisfy the HEAT semispan aerodynamic and acoustic requirements. Acoustic performance of that symmetry plane will be shown.
Document ID
20020036223
Document Type
Conference Paper
Authors
Soderman, Paul T. (NASA Ames Research Center Moffett Field, CA United States)
Olson, Larry
Date Acquired
August 20, 2013
Publication Date
January 1, 1995
Subject Category
Research and Support Facilities (Air)
Meeting Information
SAE Aerotech 1995(Los Angeles, CA)
Funding Number(s)
PROJECT: RTOP 537-03-20
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.