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 61 for “"axial velocity"”.
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Precession damping and axial velocity control of a lightweight reentry vehicle
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1989.
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A Hybrid Vortex Solution for Radial Equilibrium in Axial Compressors
… equation for three dimensional design in axial compressors is generated. One of the most common used vortex solutions is Free Vortex. However, it ignores the fact that axial velocity varies with radius. The Hybrid Vortex includes axial velocity distribution with radius, which gives a more …
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Large eddy simulation of turbulent vortices and mixing layers
… core and the surroundings. The mean tangential velocity decays due to this exchange of angular momentum. Second, the generation and decay of turbulent structures in a vortex with an axial velocity deficit are studied. The presence of a destabilizing wake-like axial velocity field in an otherwise …
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The effect of Whitcomb winglets and other wingtip modifications on wake vortices
… Stability Wind Tunnel. The vortex tangential and axial velocity profiles are compared at five and twenty chord lengths downstream. Primary focus is placed on the Whitcomb winglet and its individual components, the upper winglet alone and the lower winglet alone. It is shown that the Whitcomb …
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Flow Characteristics and Heat Transfer for Pressure and Electric Field Driven Laminar Flow With Temperature-Dependent Properties in a Pipe With Irregular Cross Section
… number. However, it has only a minor effect on axial velocity and friction factor.
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Visualization and velocity measurement of unsteady flow in a gas generator using cold-flow technique
… run for flow visualization and measurement of axial velocity at different frequencies ranging from 4 Hz to 12 Hz. Flow visualization showed that the incoming flow was a complex jet flow conformed to a cylindrical enclosure, while the outgoing flow resembled the venting of a pressurized vessel. …
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Rotor Wakes; Formations, Interactions, and Design
… an isolated comparison of the influences of jet axial velocity, tangential (swirl) velocity, and wake vortex features on wing/body integration considerations. Using the integrated axial thrust across the same radial volume it was found that peak axial velocity across each propulsive device was …
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A study of droplet velocity and diameter measurements in a reacting diesel spray produced by a flow-blurring injector
… well-known technique to measure the diameter and velocity of spherical particles. PDPA is used in many research applications including fuel injection, spray, and combustion. PDPA system does not disturb the flow being measured, and thus, it is preferable over intrusive measurement techniques. A …
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CFD Study of Taylor-Like Vortices in Swirling Flows
… toroidal vortices spaced regularly along the axial direction appear under certain critical conditions. The dimensionless control parameter governing the formation of the Taylor-like vortices is expressed as the ratio of the tangential to axial velocity components.</p>
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Numerical Investigations of Bubble Column Equipped with Vertical Internals in Different Arrangements
… distance has a significant impact on the liquid axial velocity distribution and flow recirculation. Decreasing the tube-to-tube space reduces the axial liquid flow and the height of internals affects the liquid recirculation only in homogeneous flow regime.
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Experimental determination of the flow field velocity and strain rate in a laminar opposed flow H₂/air diffusion flame, via laser doppler anemometry
… was to experimentally determine the flow field velocity and corresponding strain rate under different operating flow conditions. An axisymmetric opposed jet burner was employed in this experiment where air was supplied to one circular tube, while fuel and diluent were supplied to the opposing …
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Experimental determination of strain rates in stretched laminar diffusion flames
… laser Doppler anemometer was used to measure the axial and radial velocity components of hydrogen-air counterflow diffusion flames (CFDF). An axisymmetric opposed jet burner (OJB) used seeded air in one cylindrical tube, and a hydrogen-nitrogen mixture in the opposing cylindrical tube. Velocity …
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Spectral analysis for rod formation dynamics
… fibers with a thin membrane. This rod is driven axially and cut into segments. Measurements of pressure, temperature, axial force, axial velocity, horizontal and vertical displacements were taken of the rod during normal operating conditions at various speeds. The time signal for these tests were …
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Application of a modified k-[epsilon] turbulence model to gas turbine combustor geometries
… zone for both cases. The large swirl and axial velocity gradients, which are diffused by the standard k-epsilon model, are preserved by the Chen model. The overprediction of turbulent eddy viscosity in regions of high shear, which is characteristic of k-epsilon, is controlled by the Chen …
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Kelvin-Helmholtz Instability in Magnetized Plasma
… growing at the plasma-field boundary, where a velocity gradient perpendicular to the plasma velocity forms. The magnetized Kelvin-Helmholtz instability was further investigated using intrinsically magnetized pulsed power-generated plasma flows. The flows were produced by using quasi-planar …
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Experimental Investigation of Sheared Flow Stabilization of Z-pinches
… MHD calculations of z-pinch stability with an axial velocity shear predict that a supersonic axial flow with a radial gradient is capable of stabilizing the MHD instabilities [3][4][5]. A sheared flow can be introduced to a pinch by using a conical wire array with a fine metallic wire on axis …
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Numerical analysis of high pressure injection of natural gas into diesel engine combustion chambers
… details of jet behaviour such as radial and axial velocity and concentration profiles when compared to known data. The code has been modified to use a compressing and expanding grid to simulate the effects of piston motion. A model of a fixed geometry combustion chamber revealed that the most …
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Investigation of the GEM MPD thruster using the MACH2 magnetohydrodynamics code
… with a radius ratio of 5. Electron density and axial velocity values were analyzed and compared with experimental data. The simulated magnetic field near the cathode was shown to be very close to experimental measurements. Pressure simulation results were assessed, which indicated the presence …
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Design Optimization of the First Stage Fan Blade of a Low Bypass Turbofan Engine
… effect of varying other parameters, such as the axial velocity at the rotor's trailing edge, circumferential velocity at the rotor's trailing edge, and the blade hub-to-tip ratio, over a wide range. The preliminary rotor geometry and its complimentary fluid flow field parameters were then solved …
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An examination of flow characteristics in collapsing elastic tubes
… flow rate into and out of the models as well as axial pressure drop were monitored. It was found that the driven collapse of the vessel acts as a pump, the effectiveness of which is dependent on upstream and downstream resistance. There was noted a difference in the volumetric flow curves …
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