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Time-Averaged Velocity, Temperature and Density Surveys of Supersonic Free JetsA spectrally resolved molecular Rayleigh scattering technique was used to simultaneously measure axial component of velocity U, static temperature T, and density p in unheated free jets at Mach numbers M = 0.6,0.95, 1.4 and 1.8. The latter two conditions were achieved using contoured convergent-divergent nozzles. A narrow line-width continuous wave laser was passed through the jet plumes and molecular scattered light from a small region on the beam was collected and analyzed using a Fabry-Perot interferometer. The optical spectrum analysis air density at the probe volume was determined by monitoring the intensity variation of the scattered light using photo-multiplier tubes. The Fabry-Perot interferometer was operated in the imaging mode, whereby the fringe formed at the image plane was captured by a cooled CCD camera. Special attention was given to remove dust particles from the plume and to provide adequate vibration isolation to the optical components. The velocity profiles from various operating conditions were compared with that measured by a Pitot tube. An excellent comparison within 5m's demonstrated the maturity of the technique. Temperature was measured least accurately, within 10K, while density was measured within 1% uncertainty. The survey data consisted of centerline variations and radial profiles of time-averaged U, T and p. The static temperature and density values were used to determine static pressure variations inside the jet. The data provided a comparative study of jet growth rates with increasing Mach number. The current work is part of a data-base development project for Computational Fluid Dynamics and Aeroacoustics codes that endeavor to predict noise characteristics of high speed jets. A limited amount of far field noise spectra from the same jets are also presented. Finally, a direct experimental validation was obtained for the Crocco-Busemann equation which is commonly used to predict temperature and density profiles from known velocity profiles. Data presented in this paper are available in ASCII format upon request.
Document ID
Document Type
Conference Paper
Panda, Jayanta
(Ohio Aerospace Inst. Brook Park, OH, United States)
Seasholtz, Richard G.
(NASA Glenn Research Center Cleveland, OH, United States)
Elam, Kristie A.
(Akima Corp. Fairview Park, OH, United States)
Mielke, Amy F.
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
August 22, 2013
Publication Date
January 1, 2005
Subject Category
Fluid Mechanics And Thermodynamics
Report/Patent Number
Meeting Information
ASME Fluids Engineering Conference, Forum on high speed jet flows(Charlotte, North Carolina)
Distribution Limits
Work of the US Gov. Public Use Permitted.
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