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 28 for “"Scalar Transport"”.
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Momentum and scalar transport in vegetated shear flows
… that describe the salient hydrodynamic and transport features of vegetated flows. Flume experiments were conducted with dowels and buoyant polyethylene strips used to mimic rigid canopies and flexible seagrass meadows respectively. Although traditionally treated as rough boundary layers, …
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Propagation and scattering of beam waves in vegetation using scalar transport theory
… can be studied effectively by using transport theory. In prior studies, theories have been developed for microwave and mm-wave propagation in vegetation using transport theory for continuous wave and pulsed signals. In this study, the theory has been extended to the more realistic …
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Passive Scalar Transport by Non-Smooth Incompressible Fluids: Mixing and Vanishing Viscosity
… rigorous mathematical analysis of the passive scalar transport model. Our investigation centers on the behaviour of fluid flows characterised by vector fields of lower regularity—a crucial feature in understanding turbulent dynamics. Through careful examination of these flows in various …
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Improving parameterization of scalar transport through vegetation in a coupled ecosystem-atmosphere model
… models currently parameterize subcanopy scalar transport using a rough-wall boundary eddy diffusivity formulation. This formulation predicts unreasonably high soil evaporation beneath tall, dense forests and low soil evaporation beneath short, sparse grass. This study investigates …
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A numerical and experimental study of the scalar transport at a turbulent liquid free surface
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1989.
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Theoretical and numerical aspects of advection-pressure splitting for 1D blood flow models
… (1D) blood flow equations with a passive scalar transport equation. Our analysis involves a two-step framework that includes splitting at the level of partial differential equations (PDEs) and numerical methods for discretizing the ensuing problems. This study is inspired by the original …
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An experimental investigation of organized structure and mixing in compressible turbulent free shear layers
The large scale structure and scalar transport characteristics of compressible turbulent mixing layers have been experimentally investigated at various levels of compressibility in order to study the fundamental effects of compressibility on the nature of the mixing layer. Nonintrusive optical …
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Hydrodynamic and transport phenomena at the interface between flow and aquatic vegetation : from the forest to the blade scale
… kelp produce a wide array of hydrodynamic and scalar transport phenomena. At the kilometer scale of the kelp forest, coastal currents transport nutrients, microorganisms and spores. But, kelp forests exert a drag force on currents, causing the flow to decelerate and divert as it encounters the …
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Prediction of turbulent mixing at the interface of density stratified, shear flows using CFD
… In all the simulations a single fluid, scalar transport multiphase model and the k-epsilon turbulence model were used. In the simulations involving miscible fluids an interfacial thickness relationship given by delta/H∼(Ri*)--2.1 and an entrainment relationship given by …
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A fast 3D particle method for simulations of buoyant and reacting flows
… problems. The first is the solution of a generic scalar transport equation by advecting and diffusing the scalar gradient along a particle trajectory and onto a mesh, respectively, and recovering the scalar values using a Biot-Savart-like summation. The second is the accurate, high-resolution …
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Multigrid solution for high-order discontinuous Galerkin discretizations of the compressible Navier-Stokes equations
… elements in a p = 0 discretization of the scalar transport equation. Fourier analysis of 2-D scalar convection-diffusion shows that the element-line Jacobi smoother as well as the simpler element Jacobi smoother are stable independent of p and flow condition. Mesh refinement studies for …
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Modeling Outdoor Air Pollution and the Urban Form
… thesis develops a solver for aerial pollutant transport by adding a passive-scalar transport equation to buoyantBoussinesqPimpleFoam, the OpenFOAM transient solver for buoyant, turbulent flow of incompressible fluids, with Reynolds Averaged Navier-Stokes (RANS) turbulence modeling. It then …
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A 3-dimensional h-adaptive algorithm for species transport prediction
… the Navier-Stokes equations for fluid flow and scalar transport; This h-adaptive algorithm, in combination with the finite element solver, has been designed to solve simple to moderately complex 3-dimensional problems on high-end PC's with at least 16 megabytes of ram, and more complex …
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A discontinuous Galerkin spectral element method compressible flow solver
… for effective regularization of challenging scalar transport problems in high-order methods and have found application in shock-capturing for the compressible flow solver. Moving-mesh capabilities via the arbitrary Lagrangian-Eulerian method are verified and have enabled simulation of complex …
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Model order reduction in the frequency domain via spectral proper orthogonal decomposition
… using the example PDE of steady passive scalar transport in an inhomogenous, time-invariant flow field. Finally, we compare the performance of our ROM with the standard POD-Galerkin ROM in terms of accuracy and computational speedup.
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Quantification of Mixing in Microchannels
… of mixing: (a) via calculation of a passive scalar transport equation, (b) by following fluid particle trajectories and calculating the statistics. The first approach suffers from presence of numerical diffusion. The second approach is usually used to only obtain qualitative information …
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Modelling the generation of toxic combustion products and its transport in enclosure fires
… products generated in enclosure fires can be transported throughout the enclosure causing death and injury to occupants and a great deal of damage to property and the environment. The ability to estimate the generation and transport of toxic combustion products in real fire scenarios involving …
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Uncertainty assessment for CFD using error transport equation
… difference and/or finite volume approach. A transport equation for the error (referred to as the error transport equation) is formulated and solved along with a localized residual estimation based on the modified equation concept. Spatiotemporal evolution of the error distribution is mapped …
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Multi-Scale Localized Perturbation Method for Geophysical Fluid Flows
… URANS equations with turbulence model and scalar transport within OpenFOAM is then documented, followed by verification cases. A stratified wake collapse case in a domain containing a background shear layer is then presented, showing how complex internal gravity wave-shear layer …
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Turbulent Simulations of a Buoyant Jet-in-Crossflow
… is utilized. Temperature and salinity scalar transport equations are utilized in conjunction with a linear equation of state (EOS) to obtain the density field and thus the buoyancy forcing. Comparing simulation data to experimental data of a point heat source in a stratified environment …
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