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 41 for “"Variable-Density"”.
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Stationary edge flames in a wedge with hydrodynamic variable-density interaction
Edge flames are a canonical two-dimensional flame structure appearing in more complicated combustion problems, such as lifted jet flames and in the dynamics of the growth and repair of flame holes in nonpremixed turbulent combustion. Typical theoretical configurations to study edge flames are …
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Lightweight concrete : investigations into the production of variable density cellular materials
… creating a cellular lightweight concrete with variable density that can be cured at room temperature. Most aerated concretes traditionally require high temperature and high pressure curing; the goal of this research is to create a lower embodied energy product through the use of room …
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Effects of Compressibility and Variable-Density on the Instability Growth within Buoyancy-Driven Shear Layers
… the effects of compressibility and compositional variable density (VD) on the instability growth within buoyancy-driven shear layers (BSL), which share characteristics with the canonical Rayleigh-Taylor (RT/RTI) and Kelvin-Helmholtz (KH/KHI) instabilities. The 2D simulations are performed in a …
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Coupling tough2 and SEAWAT variable-density models to understand potential geologic carbon sequestration impacts on groundwater resources
… TOUGH2 is suitable for simulating multiphase and variable density flow problems such as GCS, while SEAWAT is suitable for variable density, groundwater flow problems. Rather than using a single TOUGH2 model, coupling SEAWAT and TOUGH2 lowers the computational cost of modeling this system, allowing …
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Three-dimensional effects on flag flapping dynamics ; [and], Study and modeling of incompressible highly variable density turbulence in the bubbly wake of a transom stern
Part I: A classic problem in the field of fluid-structure interaction is the flapping-flag instability. Fluid-mechanical studies of the phenomenon date back to the 19th century, increased in number in recent years with increasingly accurate representations for the coupled fluid-structure …
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Solution of strained edge flames by a boundary value method
… the nonlinear eigenvalue problem based on the variable-density zero Mach number reactive Navier-Stokes equations. It employs a homotopy method to gradually map the solutions from the constant-density edge flame to the more challenging variable-density edge flame. The flow and the combustion …
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The use of numerical groundwater model to improve effectiveness of subsurface drainage system in irrigated field
The research demonstrates that Three-Dimensional Variable-Density Groundwater Flow<br/>models such as the SEAWAT model can be effectively used for design of subsurface<br/>drainage systems for controlling salt concentration in the root zone on salt affected<br/>irrigated land. The SEAWAT model was …
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Modelling, Migration, and Inversion for Angle Domain Common Image Gathers
… However, the FWI sensitivity kernel in acoustic variable-density media differs by parameterization method, and the time-domain gradient equation in velocity-density media has multiple arguments. I tested several velocity-density gradient equations in time-domain full waveform inversion (FWI) for …
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North American and Greenland modern pollen data for multi-scale paleoecological and paleoclimatic applications
… available for almost all of North America, with variable density. The squared-chord distance computed between samples shows that most modern pollen samples find analogues in the same vegetation zone and the temperature and precipitation computed from the best analogue are highly correlated with …
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Regional-Scale Impacts of Fluid Composition and Geologic Structure for Injection-Induced Seismicity in the Southern U.S. Midcontinent
… seismicity by demonstrating that the density differential between injection fluids and formation brines may also drive fluid pressure into the seismogenic basement. In this thesis, variable density groundwater flow is modeled in a numerical simulation comprising parts of the Anadarko …
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Rayleigh-Taylor mixing: confinement by stratification and geometry
… stratification, and by impingement on a stable density interface. Water-based experiments are modelled using a variety of techniques, ranging from simple hand calculation of energy exchange to full three-dimensional numerical simulation. Since there are well known difficulties in modelling …
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Fluid and Pressure Dynamics in Natural and Engineered Coastal Aquifer Systems
… uses 3D numerical modeling to evaluate how variable-density flow and geological heterogeneity influence pressure response, intrusion geometry, and deformation in stressed coastal systems. Three aquifer domains are examined: homogeneous aquifers, confined aquifers with continuous clay layers, …
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Physical controls on water flow and solute transport in coastal aquifers
… MA RU N is used to simulate variably saturated, variable density groundwater flow and subsurface solute transport in coastal aquifers. To investigate evaporation effects, a classic bulk aerodynamic formulation is adopted as a module to the model MARUN for simulating groundwater flow and …
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Modeling ignition and extinction in condensed phase combustion
… analysis is carried on both constant and variable density formulations and compared the solutions to those obtained numerically. In the case of condensed phase reactants, several types of analyses are carried out at increasing levels of complexities: an asymptotic analysis valid in the …
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Advanced parallel magnetic resonance imaging methods with applications to MR spectroscopic imaging
… the solution from data noise and model errors. Variable density k-space sub-sampling is presented to improve the reconstruction with the common uniform sub-sampling. A novel method for massively parallel MRI systems named Superresolution Sensitivity Encoding (SURE-SENSE) is proposed where …
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NEW ALGORITHMS FOR COMPRESSED SENSING OF MRI: WTWTS, DWTS, WDWTS
… have extended the CS framework by performing Variable Density Sampling (VDS) or using wavelet domain as sparsity basis generator. Recent work in this approach considers parent-child relations in the wavelet levels.</p> <p> This paper further extends the prior approach by utilizing the entire …
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Multiphysics modelling of geometrically-complex flow metering devices
… or more fluids, particularly in the presence of variable geometries. This is essential for multiphase flow metering, which allows for production optimisation in oil fields for example. In this work, a novel approach for the numerical simulation of problems involving free-surface flows interacting …
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Micro-Scale Simulation of Evaporation, Condensation and Transport in Porous Media
… is introduced by the incorporation of wedges of variable density and amplitude on the grain surface. A further introduced complication is that the individual grains are of different mineralogy and thus of different wettability. It is observed that steam condenses first in the smallest of wedges, …
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Effect of initial conditions on the development of Rayleigh-Taylor instabilities
… arose to evaluate the performance of the variable density, RANS-type, BHR turbulent transport model. Measurements of velocity statistics necessary to initialize the model accurately have been obtained using particle image velocimetry (PIV). The performance of the BHR model was evaluated …
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