Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 44 for “"Laser doppler velocimeter"”.
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Laser Doppler velocimeter measurements in a turbulent junction vortex
… a two-color, two-component, frequency shifted laser Doppler velocimeter. The mean flow field shows the presence of a single vortex on the plane of symmetry and a singular separation point upstream of the vortex. From the measured data, the locations of the vortex center and the singular …
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Three-dimensional vibrometry via three positions of a one-dimensional laser doppler velocimeter
… This technique uses a reference-beam type laser-doppler velocimeter in three independent positions to determine the target velocity in a non orthogonal coordinate system. The transformation from non-orthogonal to orthogonal coordinate systems is analyzed. The sensitivities of the resulting …
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Experimental investigation of vortex rings and helicopter rotor wakes using a laser Doppler velocimeter,
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1973.
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Design of a 3-D rapidly scanning laser Doppler velocimeter with low SNR signal processing
… directionally sensitive three-velocity-component laser Doppler velocimeter (RSLDV) has been designed. It permits scans through three-dimensional flows to obtain space-time velocity information and almost "instantaneous" velocity profiles vital to understanding such flows. A flexible optical system …
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Design and application of a novel Laser-Doppler Velocimeter for turbulence structural measurements in turbulent boundary layers
An advanced laser-Doppler velocimeter is designed to acquire fully-resolved turbulence structural measurements in high Reynolds number two- and three-dimensional turbulent boundary layers. The new instrument combines, for the first time, new techniques allowing for the direct measurement of …
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Measurements in the bimodal region of a wing-body junction flow with a rapidly-scanning two-velocity-component laser-Doppler velocimeter
… A rapidly-scanning two-velocity-component laser-Doppler anemometer system was developed for use in investigating this flow. U and V velocity components were measured simultaneously with surface pressure measurements at the location of the most bimodal pressure histogram (x/t=-0.26). Mean …
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An Experimental Study of the Flowfield on a Semispan Rectangular Wing With a Simulated Glaze Ice Accretion
… = 1.5 million and M = 0.12 was investigated. A laser Doppler velocimeter was used to map the flowfield on the upper surface of the model in both the clean and iced configurations at $\alpha$ = 0, 4, and 8 degrees angle of attack.
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Studies in Unsteady Penetrative Thermal Convection
… a thermocouple and a two-component dual beam laser Doppler velocimeter.
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An experimental investigation of compressible, turbulent mixing layers
… and velocity measurements with a two-component laser Doppler velocimeter system. These diagnostic systems were developed for use with the mixing layer wind-tunnel facility. Many conditions were evaluated, and seven mixing layer cases were fully examined, with relative Mach numbers ranging from …
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Trailing vortex free-surface interaction
… have been carried out through the use of a Laser-Doppler-Velocimeter (LDV) for various positions of the vortex relative to the free surface. The results have shown that the vortex motion affects the free surface and is affected by it. This mutual interaction leads to the development of …
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Development and Application of Particle Image Velocimetry in High-Speed Separated Flow: Two-Dimensional Base Cavities
… 0.5 (170 m/s) for comparison to pressure and laser Doppler velocimeter (LDV) data.
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Development of an Experimental System to Generate and Characterize Supersonic Aerosol Particles Using Laser Doppler Velocimetry
… The particle velocity is measured using a laser doppler velocimeter at various positions between the exit of the nozzle and the surface of a metal substrate and found to have a maximum mean velocity of 700 m/s in helium and 350 m/s in air. The results of this thesis are used to characterize …
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An experimental investigation of the two-stream, supersonic, near wake flowfield behind a finite-thickness base
… stagnation and static pressure measurements, and laser Doppler velocimeter (LDV) measurements. The primary tool was a two-color, two-component LDV system. The data was analyzed in component approach consistent with the Chapman-Korst model.
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Velocity and Turbulence Characteristics in Flows Through Rigid Vegetation
… and vertical directions using a one-dimensional laser doppler velocimeter (LDV). Experiments were conducted under partially submerged, fully submerged and double layer flow conditions. The term double layer flow is used to describe flows that contain two different heights of vegetation. In each …
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Particle Motion in Flows: Contributions to Airborne Aerosol Measurement
… consists of a low turbulence inlet and a laser-Doppler velocimeter to sample and measure the super-micron particles all in one unit. Air enters the inlet at true air speed of the aircraft, which is a relatively high speed in the range of 100-200 ms-1. The low turbulence inlet reduces the …
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Local flowfield about large distributed roughness elements in a laminar boundary layer
… Velocity measurements were obtained with a 2-D laser Doppler velocimeter (LDV). Two-dimensional velocities, time-averaged three-dimensional velocities, turbulence intensities, and vorticity were all calculated from the measured velocities. Fluorescent-oil flow and laser-sheet/smoke-wire flow …
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Flow through Rigid Vegetation Hydrodynamics
… data were collected with a one dimensional laser Doppler velocimeter (LDV) under single layer emergent and submerged flow conditions, and through two layers of vegetation. The effects of dowel arrangement, density, and roughness are also examined under the single layer experiments. The …
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An Experimental Study of Longitudinally Embedded Vortices in a Turbulent Boundary Layer via the Non-Invasive Comprehensive LDV Technique
… using through non-invasive Comprehensive Laser Doppler Velocimeter. The results show that normalization on edge velocity is appropriate for comparison with previous work. The 1/S parameter and vq^2 parameter were found to be most appropriate to correlate the Reynolds stresses and triple …
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Boundary-layer analysis and measurement of Newtonian and non-Newtonian fluids
… water were experimentally investigated using a laser-Doppler velocimeter. Measured boundary-layer velocity profiles indicated that the flow parameter controlling the drag on a bluff body in drag-reducing flows is the turbulence intensity rather than the Reynolds number. For turbulence intensity …
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Experimental and numerical investigation of second-generation, controlled-diffusion, compressor blades in cascade.
… calculated. A standard optics, two-component, laser-Doppler velocimeter was used to characterize the flow field upstream, in the boundary layer on the suction side of the blades, and in the wake region. A numerical investigation was conducted using the rotor viscous code 3-D developed by Dr. …
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