Journal ArticleDOI
SNR and Spectral Broadening in Turbulence Structure Measurement Using a cw Laser.
Malay K. Mazumder,D.L. Wankum +1 more
TLDR
A symmetrical method of optical heterodyning of the doppler shifted signal has been developed possessing minimal instrumental spectral broadening and high SNR, which can be gainfully employed in measuringurbulence structure using a cw laser.Abstract:
A symmetrical method of optical heterodyning of the doppler shifted signal has been developed possessing minimal instrumental spectral broadening and high SNR. These advantages can be gainfully employed in measuring turbulence structure using a cw laser. The method employs two beams incident on the moving scatterer. The doppler signal frequency is independent of the scattering angle and the signal possesses no receiving aperture broadening. Typical values of signal-to-noise ratio are around 30 dB for a signal strength of 3 × 10−9 W. Optical alignment is simple. Relative merits of this technique compared to the local oscillator heterodyning method are briefly described.read more
Citations
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Journal Article
Localized fluid flow measurements with an He-Ne laser spectrometer
Y. Yeh,Herman Z. Cummins +1 more
Journal ArticleDOI
Review of LDA and PIV applied to the measurement of sound and acoustic streaming
TL;DR: A review of laser Doppler anemometry (LDA) and particle image velocimetry (PIV) with their application to the measurement of sound is presented in this paper.
Journal ArticleDOI
Two-dimensional turbulent separated flow
TL;DR: In this paper, the experimentally-observed structure of detached flows on streamlined surfaces and around sharp-edged corners is discussed in detail for steady and unsteady incompressible and compressible cases.
Journal ArticleDOI
Flow tracing fidelity of scattering aerosol in laser Doppler velocimetry
Malay K. Mazumder,K. J. Kirsch +1 more
TL;DR: An experimental method for the determination of the flow-tracing fidelity of a scattering aerosol used in laser Doppler velocimeters was developed with particular reference to the subsonic turbulence measurements.
Journal ArticleDOI
Differential Doppler Heterodyning Technique
TL;DR: Investigations of the signal-to-noise ratio (SNR) show that the maximum SNR-considering the optical setup-is obtained by measuring the frequency difference between two dopplershifted beams rather than byasuring the shift of a single beam by comparing it with a reference beam.
References
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Journal Article
Localized fluid flow measurements with an He-Ne laser spectrometer
Y. Yeh,Herman Z. Cummins +1 more
Journal ArticleDOI
LOCALIZED FLUID FLOW MEASUREMENTS WITH AN He–Ne LASER SPECTROMETER
Y. Yeh,Herman Z. Cummins +1 more
Journal ArticleDOI
Measurement of localized flow velocities in gases with a laser doppler flowmeter
TL;DR: Laser Doppler flowmeter measurement technique for localized flow velocities in gas is described in this paper, noting reliability for high flow velocity in gas and noting reliability of high flow veloities.
Journal ArticleDOI
Turbulent Flow Measurements Utilizing the Doppler Shift of Scattered Laser Radiation
R. J. Goldstein,W. F. Hagen +1 more
TL;DR: In this article, the mean turbulent velocity and intensity of turbulence in a duct flow were derived from the frequency shift of laser illumination scattered by small particles contained in the flow, and the probability function for the turbulent velocity in the duct flow was determined from the laser illumination.