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Development of a Rayleigh Scattering Diagnostic for Time-Resolved Gas Flow Velocity, Temperature, and Density Measurements in Aerodynamic Test FacilitiesA molecular Rayleigh scattering technique is developed to measure time-resolved gas velocity, temperature, and density in unseeded turbulent flows at sampling rates up to 32 kHz. A high power continuous-wave laser beam is focused at a point in an air flow field and Rayleigh scattered light is collected and fiber-optically transmitted to the spectral analysis and detection equipment. The spectrum of the light, which contains information about the temperature and velocity of the flow, is analyzed using a Fabry-Perot interferometer. Photomultiplier tubes operated in the photon counting mode allow high frequency sampling of the circular interference pattern to provide time-resolved flow property measurements. An acoustically driven nozzle flow is studied to validate velocity fluctuation measurements, and an asymmetric oscillating counterflow with unequal enthalpies is studied to validate the measurement of temperature fluctuations. Velocity fluctuations are compared with constant temperature anemometry measurements and temperature fluctuations are compared with constant current anemometry measurements at the same locations. Time-series and power spectra of the temperature and velocity measurements are presented. A numerical simulation of the light scattering and detection process was developed and compared with experimental data for future use as an experiment design tool.
Document ID
Document Type
Conference Paper
Mielke, Amy F.
(NASA Glenn Research Center Cleveland, OH, United States)
Elam, Kristie A.
(Jacobs Sverdrup Technology, Inc. Cleveland, OH, United States)
Sung, Chih-Jen
(Case Western Reserve Univ. Cleveland, OH, United States)
Date Acquired
August 23, 2013
Publication Date
June 10, 2007
Subject Category
Fluid Mechanics And Thermodynamics
Report/Patent Number
Meeting Information
22nd International Congress on Instrumentation in Aerospace Simulation Facilities(Pacific Grove, CA)
Funding Number(s)
WBS: WBS 561581.
Distribution Limits
Public Use Permitted.
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