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 27 for “"stratified flows"”.
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A model for nonlinear gravity waves in stratified flows
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, September 2002.
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Dynamics of large-amplitude internal waves in stratified flows over topography
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1997.
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The role of background flow variations in stratified flows over topography
… variations with depth, the flow of a density-stratified fluid over topography is central to various geophysical and meteorological applications and has been studied extensively. For reasons of convenience and mathematical tractability, the majority of theoretical treatments of stratified flow …
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The geometry of mixing in stratified flows: theory, experiments, observations and simulations
The world's oceans are stably stratified in density. They are also often turbulent. Turbulence, which stirs reversibly the oceans on relatively large scales, can enhance the rate at which parcels with different densities irreversibly mix. Mixing is a process that happens on (very) small scales but …
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Nonlinear interaction of long-wave distrubances with short-scale oscillations in stratified flows
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1996.
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A Multi-Resolution Direct Numerical Simulation of Turbulent Stratified Flows with High Prandtl Numbers
The turbulent structure of stratified open-channel flow subjected to a radiative volumetric heat source modelled by the Beer–Lambert law, for Prandtl numbers (𝑃𝑟) ranging 0.07 to 7, is investigated using direct numerical simulation (DNS). Most prior DNS studies of stratified turbulent open-channel …
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Numerical Simulation Of Stratified Flows And Droplet Deformation In 2D Shear Flow Of Newtonian And Viscoelastic Fluids
… and the drop in a flow problem in 2D shear flows of viscoelastic and/or Newtonian fluids. The code is validated against linear stability theory for the two-layer flow case and against experimental and other documented numerical investigations for the droplet-matrix case.
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Evaluation of RANS-Based Turbulence Models for the Propagation of Stratified Fronts in Buoyancy-Driven Flow
… buoyancy-driven f lows, including thermally stratified flow. Inaccuracies in these cases are often attributed to the Reynolds analogy, a simplification of the turbulent heat flux. To evaluate the validity of the Reynolds analogy under thermal stratification, the HiRJet experiment was …
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Uma equação para o cálculo do atrito entre fases em escoamentos turbulentos estratificados em tubulações circulares
Multiphase flows are present in several areas of the industry. Modeling these types of flow are, therefore, imperative to engineering. In literature, there are several methods to calculate friction pressure losses in such processes. These methods involve friction factors, parameters that depend on …
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Mixing in stably stratified turbulent flows: improved parameterizations of diapycnal mixing in oceanic flows
… phenomenon in both natural and engineered flows. Fundamental understanding and quantitative prediction of turbulent mixing in stratified flows is a challenging problem, with a broad range of applications including (but not limited to) prediction of climate, ocean thermohaline circulation, …
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Magneto-thermal Instability in Dilute Magnetized Plasmas
… gradient, destabilises otherwise stable entropy-stratified flows (according to the classic Schwarzschild criterion) via the magneto-thermal instability (MTI) and generates turbulence. The MTI is relevant in the outskirts of galaxy clusters, where it may supply a source of observed turbulence in …
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Estudo de modelos de dois fluidos acoplados ao método FCT em escoamentos bifásicos
Numerical simulation of two-phase flows is a tool of great importance to various areas of industry, especially in the oil and gas industry, in predicting the behavior of the flows according to the main parameters of the problem. This work aims to study two different two-phase flow models, named …
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CFD Analyses of Flow Structures in Air-Ingress and Rod Bundle Problems
… instability of the gravity-driven stratified flows inside a coaxial pipe and the effects caused by two types of spacers at the downstream of the rod bundle problem. Richardson extrapolation is used for the grid independent study. Simulation results give good agreements with the …
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Nonlinear effects on interfacial wave growth into slug flow
… model for predicting interfacial instability in stratified flows. This linear instability occurs when the lower phase inertia and the pressure from the upper phase overcome the stabilizing effects of gravity and surface tension. This mechanism is most unstable to short waves and does not allow …
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On vortex rings impacting a sharply-stratified interface
… the dynamics of vortex rings impacting a sharply-stratified density interface. This problem has a long history and is important for understanding how individual eddies in stratified turbulence mix the density field. We tackle this problem using a combination of experimental, numerical and …
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Experimental and numerical investigation of turbulence in Stable Boundary Layer flows
… current understanding of turbulence in stably stratified flows. An extensive literature review is presented on the mechanisms governing turbulence under stratified conditions, with a special focus on the Richardson number parameter, as it is often adopted as a switch to turn turbulence …
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An experimental study of the atmospheric boundary layer modified by a change in surface roughness and surface temperature
… These results for moderately, thermally stratified flows compare quite well with the Kansas data which were obtained in the surface layer. The results for very stable flow (z/L > 2.0) do not follow the same trend as was established in the moderately stable range.
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The effect of operating conditions on emissions from a two-stage lump coal combustor
… in the secondary combustion zone, and highly stratified flows are created by certain burning conditions. The CO oxidation model does not correlate well with the experimental results since possible CO formation from hydrocarbons, and stratified flow effects are not considered.
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The flow stability of linear low-density polyethlene at polymer and metal interfaces
… melt fracture on the interface behavior in stratified bicomponent flow has been examined. First, the factors and conditions leading to the onset of surface melt fracture in linear low-density polyethylene (LLDPE) were identified using fluoro-elastomer (FE) as a blending additive and as a die …
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Energetics and mixing in stratified turbulent flows
… the upwelling of water through the stably stratified ocean interior, needed to close the global circulation, is only possible through the enhanced vertical mixing resulting from turbulence. The transport of heat, carbon and nutrients is also affected by this mixing. Understanding its …
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