Differential Equations Partial Numerical Solutions
Mostrando 13-24 de 26 artigos, teses e dissertações.
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13. A study of the spread of dengue using partial differential equations and fuzzy logic / Um estudo sobre o espalhamento da dengues usando equações diferenciais parciais e logica fuzzy
The aim of this work is to study dengue and, with this purpose, some mathematical models were created to simulate its evolution in the southern district of the city of Campinas. The human population was subdivided into three compartments, according to the state of the individuals { susceptible, infectious or recovered. The interaction between these different
Publicado em: 2009
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14. Simulação numérica do escoamento bifásico em meios porosos heterogêneos empregando uma formulação semi-implícita, imitadores de fluxo e o método dos volumes finitos / Numerical simulation of two-phase flow in heterogeneous porous media applying a semi-implicit formulation, flux limiter and finite volume method
A new numerical method is proposed for the solution of two-phase flow problem in petroleum reservoirs. The two-phase (water and oil) flow problem is governed by a pressure-velocity equation coupled to a saturation equation. For computational eficiency an operator spliting technique is used; distinct time steps can be used for the computation of transport and
Publicado em: 2009
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15. Problemas inversos sobre a esfera / Inverse problems of the sphere
The objective of this thesis is the development of algorithms to determine the solutions, and for determination of sources of, the equations of Poisson and heat conduction for a sphere. We establish the form of equations of Poisson and heat on the sphere, and developed iterative methods, based on a icosaedral mesh and its dual mesh, to obtain the solutions f
Publicado em: 2008
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16. DFLD-EXP: uma solução semi-analítica para a equação de advecção-dispersão / DFLD-EXP: a semi-analytic solution for the advection-dispersion equation
A equação de advecção-dispersão possui grande importância na engenharia e nas ciências aplicadas. No entanto, como é bem conhecido, a obtenção de uma solução numérica apropriada para essa equação é um problema desafiador tanto para engenheiros como para matemáticos, físicos e outros profissionais que trabalham com a modelagem de fenômenos
Publicado em: 2008
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17. Novos esquemas centrais de diferenças finitas para a simulação de escoamentos multifásicos em reservatórios de petróleo / New finite-difference central schemes applied to multiphase flows in petroleum reservoirs
Os escoamentos bifásicos incompressíveis água-óleo são modelados por um sistema de equações diferenciais parciais nas incógnitas velocidade, pressão e saturação. Neste trabalho é apresentado um novo método numérico em duas dimensões espaciais para a resolução numérica da equação de transporte de massa. Suas principais características sã
Publicado em: 2007
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18. Numerical solution of the Euler equations for representation of transonic flows over airfoils / Solução numérica das equações de Euler para representação do escoamento transônico em aerofólios
The study of aerodynamic modeling methods for the transonic flow regime is of great importance in aeronautical engineering. Major challenge on the treatment of those flows is on their nonlinear features due to compressibility effects and shock waves (appearance). Such nonlinear effects present a strong influence on aerodynamic performance, as well as they ar
Publicado em: 2003
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19. Análise e implementação de esquemas de convecção e modelos de turbulência para simulação de escoamentos incompressíveis envolvendo superfícies livres. / Analysis and implementation of convection schemes and turbulence models for simulation of incompressible flows involving free surfaces.
A considerable part of fluid flows encountered in technological applications is characterised by involving high-Reynolds numbers, especially those in turbulent regime and with free-surface. It is extremely difficult to obtain representative numerical solutions for this class of problems, due to the non-linear nature of the partial differential equations invo
Publicado em: 2001
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20. Modelo para analise de deslocamento miscivel no meio poroso usando a teoria dos canais de fluxo
This work describes a model for the analysis of a two-components, single phase miscible displacement, considering both homogeneous and heterogeneous reservoirs, and constant total mobility (M =1). The streamtubes are computed from the solution of the partial differential equation of the Stream Function. The discretization of such equation results in a pentad
Publicado em: 1998
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21. SOLUÇÕES NUMÉRICAS PARA PLOBLEMAS DE OTIMIZAÇÃO DE FORMAS GEOMÉTRICAS ASSOCIADAS À EQUAÇÕES DIFERENCIAIS PARCIAIS ELÍTPTICAS / NUMERICAL SOLUTIONS FOR SHAPE OPTIMIZATION PROBLEMS ASSOCIATED WITH ELLIPTIC PARTIAL DIFFERENTIAL EQUATIONS
This work is directed at the problem of determining numerical solutions for shape optimization problems associated with elliptic partial differential equations. Our primarily motivation is the problem of determining optimal shapes in order to minimize the heat lost of a body, given a fixed volume of insulation and a fixed internal (or external) geometry. The
Publicado em: 1991
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22. Resolução numérica de equações de transporte de cargas elétricas através de isolantes / Numerical solutions of equations describing electric charge transport through insulating materials
Numeral methods for solving partial differential equations of the hiperbolic type, governing some problems of transport of electric charge in dielectrics are presented and then applied to four specific problems: injection of charge via an ohmic contact into a sample with a constant applied voltage; transport of a pulse of charge through a sample in the open
Publicado em: 1988
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23. Approximate solutions of problems involving charge transport in dielectrics using Galerkins method / Soluções aproximadas pelo Método de Galerkin de problemas envolvendo o transporte de cargas em isolantes.
Approximate solutions for some problems of charge transport in dielectrics, unsolved yet by exact methods, are presented using Galerkins Method. This allows to transforming the system of partial differential equations, describing transport with trapping, into a system of ordinary differential equations which are, then, integrated numerically. Whenever possib
Publicado em: 1982
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24. Conservative front tracking and level set algorithms
Hyperbolic conservation laws are foundational for many branches of continuum physics. Discontinuities in the solutions of these partial differential equations are widely recognized as a primary difficulty for numerical simulation, especially for thermal and shear discontinuities and fluid–fluid internal boundaries. We propose numerical algorithms that
The National Academy of Sciences.