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Time-dependent local density measurements in unsteady flowsA laser-induced fluorescence technique for measuring the relative time-dependent density fluctuations in unsteady or turbulent flows is demonstrated. Using a 1.5-W continuous-wave Kr(+) laser, measurements have been obtained in 0.1-mm diameter by 1-mm-long sampling volumes in a Mach 3 flow of N2 seeded with biacetyl vapor. A signal amplitude resolution of 2% was achieved for a detection frequency bandwidth of 10 kHz. The measurement uncertainty was found to be dominated by noise behaving as photon statistical noise. The practical limits of signal-to-noise ratios have been characterized for a wide range of detection frequency bandwidths that encompasses those of interest in supersonic turbulence measurements.
Document ID
19790054046
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Mckenzie, R. L.
(NASA Ames Research Center Moffett Field, CA, United States)
Monson, D. J.
(NASA Ames Research Center Moffett Field, CA, United States)
Exberger, R. J.
(NASA Ames Research Center Moffett Field, Calif., United States)
Date Acquired
August 9, 2013
Publication Date
June 1, 1979
Subject Category
Instrumentation And Photography
Report/Patent Number
AIAA PAPER 79-1088
Meeting Information
Meeting: American Institute of Aeronautics and Astronautics, Thermophysics Conference
Location: Orlando, FL
Start Date: June 4, 1979
End Date: June 6, 1979
Sponsors: American Institute of Aeronautics, Astronautics
Accession Number
79A38059
Distribution Limits
Public
Copyright
Other

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