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 33 for “"Subgrid-scale"”.
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Subgrid Scale Modeling for Large Eddy Simulation of Buoyant Turbulent Flows
… flows, requires accurate modeling of the subgrid sclae (SGS) momentum and buoyancy fluxes. This thesis presents a series of LES and direct numerical simulation (DNS) studies towards a priori and a posteriori evaluation of existing SGS models, and development of new SGS models for the …
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Implementation of 3DPTV for turbulence analysis and subgrid-scale stress model testing of a backward-facing step flow
… data for assessment and development of Subgrid-Scale (SGS) Models. An experimental technique well-suited to this application is Three-Dimensional Particle Tracking Velocimetry (3DPTV) utilizing the epipolar line triangulation method is an accepted method of quantifying volumes of …
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Landsurface hydrology parameterization for atmospheric general circulation models : inclusion of subgrid scale spatial variability and screening with a simple climate model
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1990.
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Entropy behavior for underresolved discontinuous Galerkin discretizations of the Navier-Stokes equations
… Navier Stokes perform some compensation for subgrid scale effects, like subgrid-scale modeling in explict LES. In this work, the mathematical formulation of the finite element method is used to create a new technique for quantifying the artificial generation of entropy due to stabilization in …
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The cloud-radiative forcing of the U.S. landfalling atmospheric rivers
… the U.S. Landfalling ARs in weather and climate scales. Three crucial questions are addressed. First, how do clouds produced by the ARs modulate the moisture and heat balance of the Earth-Atmospheric system? Even though studies of ARs date back to the 90s, past research has been primarily focused …
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Large eddy simulation of compressible channel flow
… validated. The method separates the resolvable scale motions from the unresolvable (subgrid) scales by applying a spatial filter to the compressible Navier-Stokes equations. The Leonard and cross terms which appear due to the filtering procedure are modeled based on a Taylor series expansion. …
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Reduced-Order Modeling of Complex Engineering and Geophysical Flows: Analysis and Computations
… dominated turbulent flows: the dynamic subgrid-scale model and the variational multiscale model. These models, which are considered state-of-the-art in large eddy simulation, are carefully derived and numerically investigated. Since modern closure models for turbulent flows generally …
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Synoptische, diagnostische und numerische Untersuchungen der Intensitätsänderungen von tropischen Wirbelstürmen und Monsuntiefs
… the symmetric, the resolved asymmetric and the subgrid-scale contributions are fully separated. The tangential wind changes can be interpreted in terms of absolute vorticity flux, angular momentum flux, PV flux or the Eliassen-Palm flux-divergence. The corresponding eddy fluxes are compared, and …
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Study of two-way coupled particle laden turbulent flow over a backward-facing step using large-eddy simulation
… study, we perform a comprehensive assessment of subgrid-scale (SGS) models for LES by considering a two-way coupled particle-laden turbulent flow over a backward-facing step. We consider dynamic eddy viscosity, wall-adapting local eddy viscosity (WALE), and dynamic one-equation models for the …
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Wall-modeled Large-eddy Simulation Based on Building-block Flows
A unified subgrid-scale (SGS) and wall model—the building-block flow model (BFM) — for wall modeled large-eddy simulation (WMLES) is proposed by devising the flow as a collection of building blocks that enables the prediction of the eddy viscosity. The core assumption of the model is that simple …
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Large Eddy Simulation and Analysis of Shear Flows in Complex Geometries
… (inclined jet in crossflow). Verification of subgrid scale model is done through comparisons with measurements for a turbulent flow over back step, present cases of counter current shear and film cooling flow. In the first part, a three dimensional stability analysis is conducted for …
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Study of natural ventilation in buildings with large eddy simulation
… is computed directly and only the smallest scales of turbulence are modeled. This investigation has identified a filtered dynamic subgrid-scale model of LES to study natural ventilation. The experimental data from a wind tunnel, a full-scale test chamber, and other research data have been …
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Studies of Lagrangian modeling techniques with applications to deep ocean carbon sequestration
… difficult due to complications in specifying the subgrid scale variation of isopycnal slope and diffusivity in steeply sloped or convectively unstable regions, and in accurately implementing the Gent-McWilliams eddy-induced transport.
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A direct numerical simulation of fully developed turbulent channel flow with passive heat transfer
… physical space (128 x 65 x 128 in x, y, z). No subgrid scale model is employed since all essential turbulence scales are resolved. The Reynolds number is 2262, based on the half channel height and bulk velocity, and the Prandtl number is 1. The Nusselt number is predicted to be 25.36. A large …
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THE OBSERVED VARIATION OF COHERENT UPDRAFT OBJECTS WITH HEIGHT IN THE CONVECTIVE BOUNDARY LAYER
… These results will help inform refinements to subgrid scale parameterizations for the boundary layer and cloud layer processes in coarse resolution numerical models.
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Modelling of radioactive particle resuspension after a dirty bomb event
… In a prototypical study using data from a full-scale dirty bomb experiment by DRDC Canada, maximum committed effective inhalation radiation doses were calculated as 1.89E+02 μSv for the public and 1.89E-2 μSv for first responders, considering a 35.2 × (1 ± 10%) GBq dirty bomb. Subsequently, …
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