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The influence of source acceleration on acoustic signalsThe effect of aircraft acceleration on acoustic signals is often ignored in both analytical studies and data reduction of flight test measurements. In this study, the influence of source acceleration on acoustic signals is analyzed using computer simulated signals for an accelerating point source. Both rotating and translating sources are considered. Using a known signal allows an assessment of the influence of source acceleration on the received signal. Aircraft acceleration must also be considered in the measurement and reduction of flyover noise. Tracking of the aircraft over an array of microphones enables ensemble averaging of the acoustic signal, thus increasing the confidence in the measured data. This is only valid when both the altitude and velocity remain constant. For an accelerating aircraft, each microphone is exposed to differing flight velocities, Doppler shifts, and smear angles. Thus, averaging across the array in the normal manner is constrained by aircraft acceleration and microphone spacing. In this study computer simulated spectra, containing acceleration, are averaged across a 12 microphone array mimicking a flight test with accelerated profile in which noise data was obtained. Overlapped processing is performed is performed in the flight test measurements in order to alleviate spectral smearing.
Document ID
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Kelly, Jeffrey J.
(Lockheed Engineering and Sciences Co., Hampton, VA US, United States)
Wilson, Mark R.
(Lockheed Engineering and Sciences Co., Hampton, VA US, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1993
Publication Information
Publisher: Noise Control Foundation
ISSN: 0736-2935
Subject Category
Accession Number
Funding Number(s)
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