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 31 for “"laser doppler velocimetry (LDV)"”.
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Interaction between turbulent flow and saturated porous media
… simulations, flow visualisation experiments and laser Doppler velocimetry (LDV) measurements.
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Hotwire measurements of the turbulent flow into a cascade of controlled-diffusion compressor blades
… (CD) blades in order to verify Laser Doppler Velocimetry (LDV) data taken in earlier studies. Measurements were conducted at a Mach number of .25, a Reynolds number of 711000 and an inlet flow angle of 48 degrees. Turbulence profiles obtained in the pitch-wise direction were …
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An experimental investigation of the effects of base bleed in axisymmetric supersonic flow
… and shadowgraph photography, and two-component laser Doppler velocimetry (LDV). The comprehensive LDV mean velocity and turbulence measurements obtained during this study provide valuable insight into the physics of the base bleed mechanism and constitute a benchmark data set to aid analytical …
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Facility and Methodologies for Evaluation of Hydrogen-Air Mixer Performance
… visualization, schlieren flow visualization, and Laser Doppler Velocimetry (LDV) to characterize and evaluate mixer performance. Results from the two flow visualization experiments illustrate the effectiveness of the established facility. The results from the Mie scattering experiment are post …
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Development of Specialized Laser Doppler Velocimeters for High Resolution Flow Profile and Turbulence Spectral Measurements
… and be compact. Through recent advancements, laser Doppler velocimetry can now meet all of those requirements making it an important part of aerodynamicist's research toolbox. The first paper presented in this manuscript style thesis explains the development of an advanced three-velocity …
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Overview of the Skin Friction measurements on the NASA BeVERLI Hill using Oil Film Interferometry
… experimental flow measurement technique called Laser Doppler Velocimetry (LDV) are compared with OFI, and a cross-instrument study is performed. Finally, results from well-refined RANS CFD simulations are assessed with the experimental results, and critical improvement areas are identified.
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Effects of Spacing and Geometry of Distributed Roughness Elements on a Two-Dimensional Turbulent Boundary Layer
… wall flows are particularly suited to study with Laser Doppler Velocimetry (LDV) due to the fact that measurements are required near a solid surface, as well has in highly turbulent fluid. The LDV system used in this study is a fine resolution (~50 micron), three-component, fiber optic system. All …
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Turbulent structures in smooth and rough open channel flows: effect of depth
… Velocity measurements were conducted using laser Doppler velocimetry (LDV) and particle image velocimetry (PIV) systems. While on the smooth bed, mean velocity scaling in the classical logarithmic format was confirmed from the present experiments, for the deep-flow cases, turbulence …
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Blade tonal noise reduction using tail articulation at high Reynolds number
… in the active stator wake are carried out by Laser Doppler Velocimetry, LDV, and Particle Image Velocimetry, PIV, in order to investigate the effects of tail articulation. Time averaged measurements of the stator wake by LDV show that Strouhal number of the tail articulation has a dominant …
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Optical Field Instrumentation for Characterizing Particle Sampling Sensors
… size and velocity with a method similar to Laser Doppler Velocimetry (LDV). The second sensor measures particle composition with X-Ray Fluorescence (XRF) by physically sampling particles in a flow. There has been little research on applying XRF to moving particles, so experimental data were …
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Oscillatory Flow Driven by Cavity
… Star-CCM+. The experimental analysis utilized a Laser Doppler Velocimetry (LDV) system for measurements of velocity profiles to determine the oscillatory jet flow properties as well at the oscillation frequency. Cavity dimensions with a Length to Depth ratio of 2 was used with an incoming flow …
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Hemodynamic Flow Characterization of St. Jude Medical Bileaflet Mechanical and Bioprosthetic Heart Valve Prostheses in a Left Ventricular Model via Digital Particle Image Velocimetry
… measurements most of which were obtained by Laser Doppler Velocimetry (LDV) in rigid models of the aorta. Digital Particle Image Velocimetry (DPIV) has also been utilized to reveal intricate patterns of interacting shed vortices downstream of the aortic valve. The orientation of the valves …
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Experimental visualization of the near-boundary hydrodynamics about fish-like swimming bodies
… were performed up to Reynolds number 106 using laser Doppler velocimetry and particle imaging techniques. The turbulence in the boundary layer of a waving mat and swimming robotic fish were investigated. How the undulating motion of the boundary controls both the turbulence production and the …
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Unsteady Flow Behaviors Generated by Three-Dimensional Lattice Geometries as Measured by Laser Doppler Velocimetry
… (HWA) data so that it can be used with laser Doppler velocimetry (LDV) data. Then, we investigated the unsteady flow behaviors in the channel obstructed by different types of 3D lattice geometries. Distinct behaviors of the pressure distribution and the turbulence development were …
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Experimental investigation of the near wall flow structure of a low Reynolds number 3-D turbulent boundary layer
Laser Doppler velocimetry (LDV) measurements and hydrogen-bubble flow-visualization techniques were used to examine the near-wall flow structure of 2-D and 3-D turbulent boundary layers (TBLs) over a range of low Reynolds numbers. The goals of this research were (1) an increased understanding of …
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Effects of boundary roughness on turbulence in uniform open channel flow
… bed conditions provided the data analyzed. The Laser Doppler Velocimetry (LDV) measurement system was used in the “Wood’s Hole” flume which was configured with a smooth plastic, rough-sanded PVC and with 14mm glass marbles as the varying bed conditions. The flume was originally built at the …
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Laser Doppler velocimetry measurements of particle velocity fluctuations in a concentrated suspension
… tensor would be more realistic. We used laser Doppler velocimetry (LDV) to make a set of experimental observations of particle velocity fluctuations arising from inter-particle collisions in a concentrated non-colloidal suspension under nearly homogeneous shear flow in a narrow-gap …
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Flapping motion of a three-dimensional foil for propulsion and maneuvering of underwater vehicles
… 40 degrees. Wake velocities were measured using Laser Doppler Velocimetry (LDV) and Digital Particle Imaging Velocimetry (DPIV) in three ancillary experiments. First, mean velocities across the wake at five spanwise locations were recorded using LDV. The wake width was found to be the excursion …
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A hydrodynamic study of nickel suspension in stirred tanks
… and experimental results obtained with the laser Doppler velocimetry (LDV) method showed that mixing time and homogenization energy decreased with a decrease in the impeller bottom clearance. It was further shown that there is a bottom clearance range in which a draft tube can aid mixing in …
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The Development and Control of Axial Vortices over Swept Wings
… mode instability. High-speed Particle Image Velocimetry (PIV) was conducted over a 75° sweep delta wing at 40° angle of attack in the ESM Water Tunnel II at Re = 45,000. Data were taken along the axis of the vortex in the breakdown flowfield at a speed of 0.1% of the convective time scale of …
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