Thesis (M.App.Sc.) - Carleton University, 2005. / Includes bibliographical references (p. 224-244). Also available in electronic format on the Internet.

Thèse (D.Eng.)--Université du Québec à Chicoutimi, 2001. / Document électronique également accessible en format PDF. CaQCU

Thesis (M.S.)--Mississippi State University. Department of Aerospace Engineering. / Title from title screen. Includes bibliographical references.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2002. / Restricted until May 2003. Bibliography: leaves 98-101.

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xviii, 178 p.; also includes graphics (some col.) Includes bibliographical references (p. 173-178). Available online via OhioLINK's ETD Center

Thesis (Ph. D.)--University of Texas at Austin, 2005. / Supervisors: Clinton N. Dawson and Yannis Kallinderis. Vita. Includes bibliographical references.

We introduce new methods based on the L2 Optimal Transport (OT) problem and the Navier-Stokes equations to approximate a fluid velocity field from images obtained with Particle Image Velocimetry (PIV) measurements. The main idea is to consider two successive images as the initial and final densities in the OT problem, and to use the associated OT flow as an estimate of the underlying physical flow. We build a simple but realistic model for PIV data, and use it to analyze the behavior of the transport map in this situation. We then design and implement a series of post-processing filters created to improve the quality of the numerical results, and we establish comparisons with traditional cross-correlation algorithms. These results indicate that the OT-PIV procedure performs well on low to medium seeding densities, and that it gives better results than typical cross-correlation algorithms in some cases. Finally, we use a variational method to project the OT velocity field on the space of solutions of the Navier-Stokes equations, and extend it to the rest of the fluid domain, outside the particle locations. This extension provides an effective filtering of the OT solution beyond the local post-processing filters, as demonstrated by several numerical experiments. / Graduate

Neste trabalho, apresenta-se o resultado da existência de soluções fracas em domínios não-limitados para as equações de Navier-Stokes, desde que a fronteira satisfaça uma certa condição de regularidade que é necessária para a obtenção de estimativas em domínios não-limitados semelhantes à desigualdade de Poincaré em domínios limitados. Apresenta-se o desenvolvimento detalhado do método de Galerkin para as equações de Navier-Stokes em domínios não-limitados com cálculo explícito de várias constantes e com forças externas não nulas. Apresenta-se dois teoremas fundamentais: um fornecendo condições para existência de soluções do problema estacionário e o outro fornecendo condições para existência de soluções do problema não-estacionário. / In the work it is presented results of existence of weak solutions in unbounded doroains for the Navier-Stokes equations. The roain condition to obtain similar results as those for bounded doroains; for e."'Carople the Poincaré inequality; is a certain condition of regularity at the boundary of the doroain. It is presented the detailed developroent of the Galerkin roethod for the t.he Navier-Stokes equations in unbounded doroains ~vith the explicit calculat ions of many constants and ''rith non null externai forces. It is presented two basic theorern: one presenting condition for the existence of solutions for the stationary problem and the other presenting conditions for existence of solution for the non stationary problem.

A 3D parallel CFD code is written to investigate the characteristics of and differences between Large Eddy Simulation (LES) models in the context of simulating a thermal buoyant plume. An efficient multigrid scheme is incorporated to solve the Poisson equation, resulting from the fractional step, projection method used to solve the Low Mach Number (LMN) Navier-Stokes equations. A wide range of LES models are implemented, including a variety of eddy models, structure models, mixed models and dynamic models, for both the momentum stresses and the temperature fluxes. Generalised gradient flux models are adapted from their RANS counterparts, and also tested. A number of characteristics are observed in the LES models relating to the thermal plume simulation in particular and turbulence in general. Effects on transition, dissipation, backscatter, equation balances, intermittency and energy spectra are all considered, as are the impact of the governing equations, the discretisation scheme, and the effect of grid coarsening. Also characteristics to particular models are considered, including the subgrid kinetic energy for the one-equation models, and constant histories for dynamic models. The argument that choice of LES model is unimportant is shown to be incorrect as a general statement, and a recommendation for when the models are best used is given.

Made available in DSpace on 2014-06-11T19:23:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-07-24Bitstream added on 2014-06-13T20:47:57Z : No. of bitstreams: 1 pereira_whk_me_ilha.pdf: 3240220 bytes, checksum: 737a7c61a264dc8da602a9eac1498d3c (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Neste trabalho foram realizadas simulações numéricas de escoamentos viscosos, incompressíveis e transientes com efeitos de rotação em um sistema não-inercial de referência, por meio do método de elementos finitos por volumes de controle; com a metodologia de simulação de grandes escalas (LES) para a modelagem da turbulência. Os domínios de cálculo foram discretizados utilizando elementos finitos quadrilaterais de nove nós e as equações são integradas em volumes de controle ao redor dos nós dos elementos finitos. Com a aplicação da metodologia de simulação de grandes escalas (LES), as equações governantes passam por um processo de filtragem e assim as maiores escalas são resolvidas diretamente pela solução das equações de Navier-Stokes filtradas, enquanto as escalas menores são modeladas pelo modelo de viscosidade turbulenta de Smagorinsky. Alguns casos de escoamentos bidimensionais nas variáveis primitivas u, v e p aplicados às máquinas de fluxo, tanto axiais, como radias, foram realizados para estudar o efeito das acelerações centrípeta e de Coriolis, por meio do adimensional número de rotação Ro, e das instabilidades geradas nos escoamentos / In this work it has been done numerical simulations of viscous transient incompressible fluid flows with rotation effects in a non inertial system of reference, by the control volume based finite element method; with the methodology of large-eddy simulation (LES) to model turbulence. The domains of calculation are discretized in quadrilateral finite elements with nine nodes and the equations are integrated in control volumes around the node of the finite elements. By the application of LES, the governing equations are filtered and this way the large scales are directly solved by the solution of the filtered Navier-Stokes equations, while the sub-grid scales are modeled by the eddy viscosity model of Smagorinsky. Some cases of two-dimensional flows in primitive variables u, v and p applied to axial and radial turbomachines were simulated to analyze the effect of the centripetal and Coriolis accelerations, considering the dimensionless number of rotation and the instabilities generated in the flows