Acoustic background noise from sailplane-mounted microphones

Thomas B. Gabrielson, Steven M. Willits, Timothy M. Marston, Edward A. Haering, James E. Murray, Mark Stucky

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

One of many options for monitoring acoustic events at altitude is a sailplane-mounted sensor. In an attempt to determine the limiting background noise for acoustic measurements from a sailplane, in-flight measurements were made with microphones installed in a Schempp-Hirth Standard Cirrus and a Blanik L23. Recordings were made in steady gliding flight in a stable atmosphere at speeds ranging from 45 to 80 knots. The background noise from a sailplane-mounted microphone shows three distinct regions. The first region, above 100 Hz, is sensor-influenced flow noise and the pressure spectral density is well characterized by a non-dimensional relation. The second region, from several hertz to 100 Hz, is probably the result of sampling pre-existing pressure fluctuations in the atmosphere. For these measurements made in a convectively stable atmosphere, the pressure spectral density was between 0.005 and 0.01 Pa per root hertz (48 to 54 dB with respect to 20 μPa per root hertz). The third region, below 1 Hz, is dominated by pressure fluctuations that correlate strongly with altitude variations - either natural oscillations of the glider or pilot control inputs.

Original languageEnglish (US)
Title of host publicationInstitute of Noise Control Engineering of the USA - 35th International Congress and Exposition on Noise Control Engineering, INTER-NOISE 2006
Pages5016-5025
Number of pages10
StatePublished - Dec 1 2006
Event35th International Congress and Exposition on Noise Control Engineering, INTER-NOISE 2006 - Honolulu, HI, United States
Duration: Dec 3 2006Dec 6 2006

Publication series

NameInstitute of Noise Control Engineering of the USA - 35th International Congress and Exposition on Noise Control Engineering, INTER-NOISE 2006
Volume8

Other

Other35th International Congress and Exposition on Noise Control Engineering, INTER-NOISE 2006
CountryUnited States
CityHonolulu, HI
Period12/3/0612/6/06

All Science Journal Classification (ASJC) codes

  • Acoustics and Ultrasonics

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