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Dynamic Measurement of Temperature, Velocity, and Density in Hot Jets Using Rayleigh ScatteringA molecular Rayleigh scattering technique was utilized to measure time-resolved gas temperature, velocity, and density in unseeded gas flows at sampling rates up to 10 kHz. A high power continuous-wave (cw) laser beam was focused at a point in an air flow field and Rayleigh scattered light was collected and fiber-optically transmitted to a Fabry-Perot interferometer for spectral analysis. Photomultipler tubes operated in the photon counting mode allowed high frequency sampling of the total signal level and the circular interference pattern to provide time-resolved density, temperature, and velocity measurements. Mean and rms velocity and temperature, as well as power spectral density calculations, are presented for measurements in a hydrogen-combustor heated jet facility with a 50.8-mm diameter nozzle at the NASA Glenn Research Center (GRC). The Rayleigh measurements are compared with particle image velocimetry data and CFD predictions. This technique is aimed at aeronautics research related to identifying noise sources in free jets, as well as applications in supersonic and hypersonic flows where measurement of flow properties, including mass flux, is required in the presence of shocks and ionization occurrence.
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)
Date Acquired
August 25, 2013
Publication Date
July 7, 2008
Subject Category
Fluid Mechanics And Thermodynamics
Report/Patent Number
Meeting Information
14th International Symposium on Applications of Laser Techniques to Fluid Mechanics(Lisbon)
Distribution Limits
Public Use Permitted.
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