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Improvement in Rayleigh Scattering Measurement AccuracySpectroscopic Rayleigh scattering is an established flow diagnostic that has the ability to provide simultaneous velocity, density, and temperature measurements. The Fabry-Perot interferometer or etalon is a commonly employed instrument for resolving the spectrum of molecular Rayleigh scattered light for the purpose of evaluating these flow properties. This paper investigates the use of an acousto-optic frequency shifting device to improve measurement accuracy in Rayleigh scattering experiments at the NASA Glenn Research Center. The frequency shifting device is used as a means of shifting the incident or reference laser frequency by 1100 MHz to avoid overlap of the Rayleigh and reference signal peaks in the interference pattern used to obtain the velocity, density, and temperature measurements, and also to calibrate the free spectral range of the Fabry-Perot etalon. The measurement accuracy improvement is evaluated by comparison of Rayleigh scattering measurements acquired with and without shifting of the reference signal frequency in a 10 mm diameter subsonic nozzle flow.
Document ID
Document Type
Conference Paper
Fagan, Amy F.
(NASA Glenn Research Center Cleveland, OH, United States)
Clem, Michelle M.
(NASA Glenn Research Center Cleveland, OH, United States)
Elam, Kristie A.
(Jacobs Technology, Inc. Cleveland, OH, United States)
Date Acquired
August 25, 2013
Publication Date
January 9, 2012
Subject Category
Report/Patent Number
AIAA Paper-2012-1060
Meeting Information
50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition(Nashville, TN)
Funding Number(s)
WBS: WBS 561581.
Distribution Limits
Public Use Permitted.
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