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 35 for “"low-turbulence"”.
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The design, development and construction of a low-noise, low-turbulence wind tunnel
Thesis (M.S.)--Massachusetts Institute of Technology. Dept. of Mechanical Engineering, 1967.
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The Design, Fabrication, and Evaluation of a Low-Speed, Low-Turbulence, Anechoic Wind Tunnel
… reduction techniques in propellers and fans, a low-speed, low-turbulence, anechoic wind tunnel was designed, fabricated and evaluated at Embry-Riddle Aeronautical University.</p> <p>This open circuit wind tunnel was designed using several other existing wind tunnels as a guide and incorporated …
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Particle Motion in Flows: Contributions to Airborne Aerosol Measurement
… <p>The developed instrument 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 …
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MICRO AIR VEHICLE SCALE GUST-WING INTERACTION IN A WIND TUNNEL
… the creation of a vertical gust generator in a low speed, low turbulence wind tunnel through the use of an actuated fan placed below the tunnel and ducted through its floor. Gusts of up to 40% of the freestream velocity were created. Characterization of the gust generator is shown, and its …
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Effects of Aero-Propulsive Interactions for Various Wing Integration Techniques on Electric Ducted Fan Performance
… symmetric airfoil design, the upper surface and lower surface integration was studied. This rig permitted to study such configuration in the low-turbulence tunnel at lower airspeeds and mostly the cruise condition. For these tests, a Clark-Y duct shape coupled with Schuebeler Technologies …
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Numerical investigation of the influence of elevated turbulence levels on the cooling effectiveness of an anti-vortex hole geometry
… a commercial CFD code (STAR-CCM+) with varying turbulence intensity and length scale using the k-o SST turbulence model. Both steady and unsteady results were considered in order to investigate the effects of freestream turbulence intensity and length scale on this novel anti-vortex hole (AVH) …
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Cascade performance of double circular arc compressor blades at high angles of attack
… uniform velocity profiles and control of inlet turbulence are discussed. The problem of maintaining two-dimensional flows at high angle of attack was addressed. A tunnel capable of testing cascades of compressor blades at angles of attack up to seventy-five degrees was constructed. Performance …
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Excitation of wave packets and random disturbances in a boundary layer
… The experiments were conducted in the VPI & SU low turbulence wind tunnel. The flat plate model was constructed from an aluminum-paper honeycomb laminate and an aluminum leading edge with an elliptical profile. A theoretical model was developed to verify the random and step-function-form motion …
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Emissions reduction benefits of adapting electronic closed loop fueling control on a mechanically controlled spark-ignited engine
… automotive regulations. The engine's quiescent, low swirl, low turbulence and low compression ratio combustion chamber design restricts the total benefits realized from the conversion. These emissions reduction benefits demonstrated here are immediately applicable to other spark-ignited non-road …
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Aerodynamics of a chined forebody oscillating in pitch
A low-speed experimental study of the effects of an oscillatory pitching motion on the flowfield of a chined forebody has been performed. These tests were conducted in the University of Illinois low-speed (0-240 ft/sec), low-turbulence ($<$0.1%), 3 by 4 ft, open circuit wind tunnel. The high …
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Experimental investigation of multielement airfoils for large-scale wind turbines
… were performed in the University of Illinois low turbulence subsonic wind tunnel with a chord length of approximately 1.5 feet (0.46 m) and a model span of approximately 2.8 feet (0.85 m). Results for the Reynolds number tested indicate that lift and drag do not always follow the same trends …
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Aerodynamic performance of low-to-moderate aspect ratio wings at low Reynolds numbers
… thesis presents wind tunnel results of wings of low-to-moderate aspect ratio (2$\leq$\AR$\leq$5) tested at low Reynolds numbers (40,000 to 160,000). All models tested had a chord length of 3~in and a wingspan of 7 to 17.5~in. Experiments were conducted in the low-turbulence wind tunnel in the …
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Investigation of the effect of a circular patch of vegetation on turbulence generation and sediment deposition using four case studies
… model vegetation and the effect of the patch on turbulence and mean flow. Two difference types pf vegetation were used along with two different stem densities totaling four different case studies. The spatial location of enhanced deposition correlated with the steady wake zone, which has length, …
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Investigation of the effect of a circular patch of vegetation on turbulence generation and sediment deposition using four case studies
… model vegetation and the effect of the patch on turbulence and mean flow. Two difference types pf vegetation were used along with two different stem densities totaling four different case studies. The spatial location of enhanced deposition correlated with the steady wake zone, which has length, …
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Investigating the frequency behavior of fluidic oscillators and their application as active flow control for an SNLF airfoil
… portions of the aft element. Active unsteady flow control using embedded fluidic oscillators was identified as a potential source to improve the flow field and maximize the lift of a multi-element system like the SNLF S414. The predictive model was used to design a set of fluidic oscillators to …
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Experimental investigation of turbulent flow in the near wake of a propeller
… Secondly, the mean static pressures, mean flow velocity components, and flow angularity were measured by a five port yawhead probe. The third type of measurement was made with a straight hot-wire anemometer to find mean and turbulence intensity magnitudes averaged behind the propeller disk. …
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The smart rotor wind turbine
… modification of the blade aerodynamics, thus allowing enhanced control of the rotor loads. In this thesis a number of research areas relating to the smart rotor are explored and advanced. The synthesised wind field spatial and temporal requirements are assessed, suggesting the current …
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Particle image velocimetry for natural convection in a cube at high Rayleigh numbers
… within the cavity and visualize the dominant flow structures. The low turbulence Rayleigh number regime 5.08E7<Ra<3.40E8 is examined for the first time and experimental results including streamlines, the two velocity components in the vertical and horizontal direction, Reynolds stresses, …
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"An Experimental Investigation of Showerhead Film Cooling Performance in a Transonic Vane Cascade at Low Freestream Turbulence"
… turbine components must be cooled well below these hot gas temperatures. Film cooling is a widely employed cooling technique whereby air is extracted from the compressor and ejected through holes on the surfaces of hot gas path components. The cool air forms a protective film around the …
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Flame-flow interaction during premixed and stratified swirl flame flashback in an annular swirl combustor
… between a propagating flame and the approach flow is critical to the understanding of boundary layer flashback of swirling flames. In this work, I investigated this interaction during flashback using high-speed luminosity imaging and simultaneous three-dimensional particle image velocimetry. …
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