Numerical Approximations
Mostrando 1-12 de 57 artigos, teses e dissertações.
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1. A Nodal-iterative Technique for Criticality Calculations in Multigroup Neutron Diffusion Models
ABSTRACT In this work, a nodal and iterative technique to evaluate the effective multiplication factor as well as the neutron flux, in multigroup diffusion problems, is presented. An iterative scheme, similar to the source iteration method, is implemented to decouple the system of differential equations which is the fundamental mathematical model. Then, anal
Trends in Computational and Applied Mathematics. Publicado em: 2022
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2. Numerical experiments with the Generalized Finite Element Method based on a flat-top Partition of Unity
Abstract The Stable Generalized Finite Element Method (SGFEM) is essentially an improved version of the Generalized Finite Element Method (GFEM). Besides of retaining the good flexibility for constructing local enriched approximations, the SGFEM has the advantage of presenting much better conditioning than that of the conventional GFEM. Actually, bad conditi
Lat. Am. j. solids struct.. Publicado em: 29/10/2018
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3. Simple but accurate periodic solutions for the nonlinear pendulum equation
Abstract Despite its elementary structure, the simple pendulum oscillations are described by a nonlinear differential equation whose exact solution for the angular displacement from vertical as a function of time cannot be expressed in terms of an elementary function, so either a numerical treatment or some analytical approximation is ultimately demanded. Su
Rev. Bras. Ensino Fís.. Publicado em: 21/09/2018
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4. Verificação da solução das equações de Saint-Venant com base no método difusivo de lax para propagação de vazões em canais naturais
ABSTRACT Hydrodynamic models, based on the Saint-Venant equations, represent the transient flow in water systems, and simulate flow routing over time and space. Several numerical solutions have been applied to these expressions, but often differences are found in results among distinct procedures, considering that all numerical approaches have limitations. N
RBRH. Publicado em: 20/02/2017
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5. A shell finite element formulation to analyze highly deformable rubber-like materials
Abstract: In this paper, a shell finite element formulation to analyze highly deformable shell structures composed of homogeneous rubber-like materials is presented. The element is a triangular shell of any-order with seven nodal parameters. The shell kinematics is based on geometrically exact Lagrangian description and on the Reissner-Mindlin hypothesis. Th
Lat. Am. j. solids struct.. Publicado em: 2013-11
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6. A stabilized finite element method to pseudoplastic flow governed by the Sisko relation
In this work, a consistent stabilized mixed finite element formulation for incompressible pseudoplastic fluid flows governed by the Sisko constitutive equation is mathematically analysed. This formulation is constructed by adding least-squares of the governing equations and of the incompressibility constraint, with discontinuous pressure approximations, allo
Computational & Applied Mathematics. Publicado em: 2012
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7. A special class of continuous general linear methods
We consider the construction of a class of numerical methods based on the general matrix inverse [14] which provides continuous interpolant for dense approximations (output). Their stability properties are similar to those for Runge-Kutta methods. These methods provide a unifying scope for many families of traditional methods. They are self-starting, to chan
Comput. Appl. Math.. Publicado em: 2012
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8. Indicadores de erros a posteriori na aproximação de funcionais de soluções de problemas elípticos no contexto do método Galerkin descontínuo hp-adaptivo / A posteriori error indicators in the approximation of functionals of elliptic problems solutions in the context of hp-adaptive discontinuous Galerkin method
In this work we study goal-oriented a posteriori error indicators for approximations by the discontinuous Galerkin method for the biharmonic and Poisson equations. The methodology used for the indicators is based on the dual problem associated with the functional, which is known to generate the most effective indicators. The two main error indicators based o
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 30/09/2011
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9. Comportamento crítico da produção de entropia em modelos com dinâmicas estocásticas competitivas / Critical behavior of entropy production in models with competitive stochastic dynamics
We study kinetic phase transitions and the critical behavior of the entropy production in spin models with nearest neighbor interactions subject to two Glauber dynamics, which simulate two thermal baths at different temperatures. In this way, it is assumed that the system corresponds to a continuous time Markov process which obeys the master equation. Thus,
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 25/04/2011
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10. Relaxation approaches to the optimal control of the Euler equations
The treatment of control problems governed by systems of conservation laws poses serious challenges for analysis and numerical simulations. This is due mainly to shock waves that occur in the solution of nonlinear systems of conservation laws. In this article, the problem of the control of Euler flows in gas dynamics is considered. Numerically, two semi-line
Computational & Applied Mathematics. Publicado em: 2011
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11. A family of uniformly accurate order Lobatto-Runge-Kutta collocation methods
We consider the construction of an interpolant for use with Lobatto-Runge-Kutta collocation methods. The main aim is to derive single symmetric continuous solution(interpolant) for uniform accuracy at the step points as well as at the off-step points whose uniform order six everywhere in the interval of consideration. We evaluate the continuous scheme at dif
Computational & Applied Mathematics. Publicado em: 2011
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12. Sobre o acoplamento fluido-casca utilizando o método dos elementos finitos / On fluid-shell coupling using the finite element method
This work consists of the development of computational tools for nonlinear geometric fluid-shell interaction analysis using the Finite Element Method (FEM). The fluid solver is explicit and its time integration based on characteristics. The computational code is able to simulate the Navier-Stokes equations for compressible flows written in the Eulerian descr
Publicado em: 2011