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Proceedings Paper

Nonintrusive double-pulse technique for measuring the velocity of high-velocity mixing/shear layers
Author(s): David A. Kalin; Jeffrey S. Haight; Bruce R. Peters; Lori C. Brooks
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Paper Abstract

A nonintrusive optical technique has been developed that measures the velocity components of high velocity mixing/shear layers. Within the high velocity turbulent media, flow structures exist that can randomly concentrate and/or redistribute incident light into unique intensity patterns. By observing the motion of these patterns over short time intervals, it is possible to deduce the velocity of the flow. A series of laboratory experiments was conducted to demonstrate the technique using the Teledyne Brown Engineering Dual Nozzle Aero-Optic Simulator (DNAOS). A binary gas, classical mixing/shear layer with a mean flow velocity of approximately 460 m/sec was generated for the tests. Two independent Q-switched Nd:YAG laser beams (1.064 micrometers ) were colinearly aligned, directed through the flow, and then recorded with a high speed CCD square array. Each laser was fired once during a camera frame, with a measured time delay of 1.36 microsecond(s) between the two laser pulses. The frames were taken at 92.5 Hz and stored for post-test analysis. By identifying the projected flow structure patterns and measuring the displacement of the patterns as recorded by the camera, two dimensional velocity components were calculated. These values were in fair agreement with mean flow velocities predicted with an empirical flow field prediction code.

Paper Details

Date Published: 21 September 1992
PDF: 6 pages
Proc. SPIE 1687, Characterization, Propagation, and Simulation of Sources and Backgrounds II, (21 September 1992); doi: 10.1117/12.137848
Show Author Affiliations
David A. Kalin, Teledyne Brown Engineering (United States)
Jeffrey S. Haight, Teledyne Brown Engineering (United States)
Bruce R. Peters, Teledyne Brown Engineering (United States)
Lori C. Brooks, Teledyne Brown Engineering (United States)

Published in SPIE Proceedings Vol. 1687:
Characterization, Propagation, and Simulation of Sources and Backgrounds II
Dieter Clement; Wendell R. Watkins, Editor(s)

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