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 152 for “"Physics, Fluid and Plasma"”.
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Particle Dynamics in Inhomogeneous Flow at Moderate to High Reynolds Number
… resolves the smallest scales in the ambient flow and in the particle wake, and provides detailed microscale information on flow-particle interaction. We address the following sequence of problems. (a) Irrotational flow: We perform DNS of stationary and freely moving particles in straining flows. …
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Theory of Instability and Nonlinear Evolution of Self -Sustained Detonation Waves
Linear stability properties and nonlinear dynamics of self-sustained detonations is investigated by means of asymptotic analysis and numerical simulations. The normal-mode linear stability analysis is carried out for gaseous detonations propagating in cylindrical tubes. By comparison of the …
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Edge-Flames and Combustion at the Microscale
… quenching limits. The behavior of premixed and nonpremixed edge-flames in tune-periodic counterflows is modeled using a constant-density approximation and a single-step Arrhenius reaction rate. Results of numerical simulations indicate that the unsteady strain rate is generally a …
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Interaction Between a Spherical Particle and Wall -Bounded Flows at Finite Reynolds Number
… wall-normal locations, the buffer region and the channel center. Near-wall region mechanisms are observed consisting of such different events as bursting, sweep, and ejection, whereas channel center can be considered as nearly isotropic turbulence. We compare the computed forces with the …
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Boundary Integral Method for Interfacial Potential Flows in Unbounded Axi-Symmetric Domains
… with surface tension driven singularities at fluid interface in general. Within this study, different regimes are found and the conditions which define them are summarized with a phase diagram.
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Integrable Vortex Motions in Unbounded and Periodic Domains
… about the motions of the vortices themselves and the fact that the advected fluid is a continuous field, Thurston-Nielsen theory establishes a lower bound on the stretching in the advected field. Some of the vortex motions investigated produce exponential stretching in the flow field. This …
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The Spatial Structure of Turbulent Rayleigh-Benard Convection
… approximately 40% of the total kinetic energy, and this fraction was found to be approximately independent of the Rayleigh number. This leads to the conclusion that the wind of turbulence (U) scales with the velocity fluctuations (ufluct), U ∼ u fluct. The visualizations indicate that the …
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The Initial Value Problem for the Zakharov System
… application of techniques developed by Bourgain and Kenig, Ponce and Vega. The equivalent fixed point problem is solved via the contraction principle in the $X\sb{s,b}$ spaces introduced by Bourgain. A detailed analysis of the nonlinear terms, exploiting the arithmetical properties of the …
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Study of Plasma/flowing Liquid Metal Interactions
Interaction between an ion beam and flowing liquid Li has been studied in the FLIRE facility as a first step towards a plasma/flowing liquid metal interaction experiment. The retained fraction of implanted helium transport was quantified as a function of energy and velocity, yielding the expected …
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Thermoelectric Magnetohydrodynamic and Thermocapillary Driven Flows of Liquid Conductors in Magnetic Fields
Experiments show that TEMHD dominates the flow in SLiDE, consistent with the theory governing these flows. This is verified by series of qualitative experiments, as well as quantitative comparison with theoretical flow predictions. This constitutes the first direct observation of TEMHD driven flow …
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Research on Edge Ionization and Star Mode Discharge Physics in Inertial Electrostatic Confinement Neutron/proton Sources
… of the IEC Star Mode incorporating the new physics understandings unearthed over the last eight years. Experimental benchmarking was successful at testing key model assumptions and validating the code simulation results. And finally, the PAIGS concept was studied and found to provide a …
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The Effects of Diabatic Heating on Storm Track Dynamics
… nonlinear primitive equation model with vertical and horizontal resolution adequate to capture shallow, short wavelength baroclinic waves. The model is forced by realistic orography and diabatic processes including radiative relaxation, surface heating and condensational heating. Time-mean …
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Propellant Surface Temperature and Plume Characteristics of Micro-Pulsed Plasma Thrusters
The micro-Pulsed Plasma Thruster is a device capable of supplying discrete impulses for propulsive maneuvering of small satellites. These devices suffer from low propellant utilization related to late-time propellant ablation, causing a drop in specific impulse and thruster efficiency. The exhaust …
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Thermo-Capillary Driven Flow Under the Influence of Rotation and Magnetic Fields
… conditions pose unique challenges for fluid handling and heat transfer applications. By controlling (curtailing or augmenting) the buoyant and thermocapillary convection, the latter being the dominant convective flow in a microgravity environment, significant advantages can be achieved …
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Charging of Macroparticles Ejected From a Pulsed Vacuum Arc
A pulsed vacuum arc discharge emits a plasma as well as macroparticles in the form of micron-sized molten droplets of cathode material. Due to their direction of flight and submicron to 100 mum diameter, these macroparticles often pose a contamination threat for both spacecraft-based thrusters, and …
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Simulation of Flowing Plasma Discharges With Applications to Lasers, Fuel Cells, and Microthrusters
… MDs deposit power to flowing Ar (at 10s Torr), and the incremental velocity, gas temperature, and thrust are studied. Due to the large surface-to-volume ratio and low Reynolds number, heat conduction to the walls and viscous losses play a significant role in determining thrust. Geometrical …
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An Experimental Investigation Into the Effect of Plasma on the Flow Features of an Axisymmetric Jet
The plasma did influence the mean and turbulent velocity profiles of the jets tested - allowing the jet core to penetrate further downstream. Large scale structure tracking indicated an increase in convective velocity of up to 5%. Heating of the shear layer by the plasma field was believed to bias …
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Computational Fluid Dynamics Methodologies for Simulation of Chemical Oxygen-Iodine Laser Flowfields
… of the airborne laser military research program and ongoing commercial development programs. As a part of these efforts, a 3-D COIL simulation model was developed based on the Computational Fluid Dynamics (CFD) code GASP which solves the conservative, finite-volume formulation of the full …
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A Low Power Pulsed Arcjet Thruster for Spacecraft Propulsion
… reduce energy losses in the storage capacitor, and greater than 85% of the initial stored energy is transferred to the arc in a unipolar pulse. A high current diode installed across the capacitor terminals is used to eliminate voltage reversals in the current. The experimental breakdown voltage …
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