Spelling suggestions: "subject:"laserdoppler"" "subject:"farbdoppler""
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Advance LDA techniques for measurement of 3D boundary layer velocity profiles on a helicopter rotorSwales, Christopher January 1994 (has links)
No description available.
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Computing and measuring the flowfield in a de-oiling hydrocycloneHargreaves, John H. January 1990 (has links)
No description available.
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Laser-based measurements of two-phase flashing propane jetsAllen, John Thomas January 1998 (has links)
No description available.
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A diode laser-based velocimeter providing point measurements in unseeded flows using modulated filtered Rayleigh scattering (MFRS)Jagodzinski, Jeremy James, 1973- 29 August 2008 (has links)
The development to date of a diode-laser based velocimeter providing point-velocitymeasurements in unseeded flows using molecular Rayleigh scattering is discussed. The velocimeter is based on modulated filtered Rayleigh scattering (MFRS), a novel variation of filtered Rayleigh scattering (FRS), utilizing modulated absorption spectroscopy techniques to detect a strong absorption of a relatively weak Rayleigh scattered signal. A rubidium (Rb) vapor filter is used to provide the relatively strong absorption; alkali metal vapors have a high optical depth at modest vapor pressures, and their narrow linewidth is ideally suited for high-resolution velocimetry. Semiconductor diode lasers are used to generate the relatively weak Rayleigh scattered signal; due to their compact, rugged construction diode lasers are ideally suited for the environmental extremes encountered in many experiments. The MFRS technique utilizes the frequency-tuning capability of diode lasers to implement a homodyne detection scheme using lock-in amplifiers. The optical frequency of the diode-based laser system used to interrogate the flow is rapidly modulated about a reference frequency in the D₂-line of Rb. The frequency modulation is imposed on the Rayleigh scattered light that is collected from the probe volume in the flow under investigation. The collected frequency modulating Rayleigh scattered light is transmitted through a Rb vapor filter before being detected. The detected modulated absorption signal is fed to two lock-in amplifers synchronized with the modulation frequency of the source laser. High levels of background rejection are attained since the lock-ins are both frequency and phase selective. The two lock-in amplifiers extract different Fourier components of the detected modulated absorption signal, which are ratioed to provide an intensity normalized frequency dependent signal from a single detector. A Doppler frequency shift in the collected Rayleigh scattered light due to a change in the velocity of the flow under investigation results in a change in the detected modulated absorption signal. This change in the detected signal provides a quantifiable measure of the Doppler frequency shift, and hence the velocity in the probe volume, provided that the laser source exhibits acceptable levels of frequency stability (determined by the magnitude of the velocities being measured). An extended cavity diode laser (ECDL) in the Littrow configuration provides frequency tunable, relatively narrow-linewidth lasing for the MFRS velocimeter. Frequency stabilization of the ECDL is provided by a proportional-integral-differential (PID) controller based on an error signal in the reference arm of the experiment. The optical power of the Littrow laser source is amplified by an antireflection coated (AR coated) broad stripe diode laser. The single-mode, frequency-modulatable, frequency-stable O(50 mW) of optical power provided by this extended cavity diode laser master oscillator power amplifier (ECDL-MOPA) system provided sufficient scattering signal from a condensing jet of CO₂ to implement the MFRS technique in the frequency-locked mode of operation.
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Theory of air velocity measurement by dual-frequency Doppler lidarEberhard, Wynn Lowell, 1944- January 1976 (has links)
No description available.
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Measurement of acoustic properties of materials using torsional wavesLi, Qingchun 12 1900 (has links)
No description available.
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An investigation of wave propagation on a cylindrical shell using laser doppler monitoringLee, Dowon 08 1900 (has links)
No description available.
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A diode laser-based velocimeter providing point measurements in unseeded flows using modulated filtered Rayleigh scattering (MFRS)Jagodzinski, Jeremy James, January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.
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On optical methods for intracerebral measurements during stereotactic and functional neurosurgery : experimental studies /Antonsson, Johan, January 2007 (has links)
Diss. (sammanfattning) Linköping : Linköpings universitet, 2007. / Härtill 5 uppsatser.
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Determination of impeller pumping capacity from laser doppler anemometer (LDA) measurements in an agitated vessel /Iamonaco, Mark A. January 1991 (has links)
Thesis (M.S.)--Rochester Institute of Technology, 1991. / Typescript. Includes bibliographical references.
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