The Piecewise Linear Discontinuous Finite Element Method Applied to the RZ and XYZ Transport Equations

The Piecewise Linear Discontinuous Finite Element Method Applied to the RZ and XYZ Transport Equations PDF Author: Teresa S Bailey
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
In this dissertation we discuss the development, implementation, analysis and testing of the Piecewise Linear Discontinuous Finite Element Method (PWLD) applied to the particle transport equation in two-dimensional cylindrical (RZ) and three-dimensional Cartesian (XYZ) geometries. We have designed this method to be applicable to radiative-transfer problems in radiation-hydrodynamics systems for arbitrary polygonal and polyhedral meshes. For RZ geometry, we have implemented this method in the Capsaicin radiative-transfer code being developed at Los Alamos National Laboratory. In XYZ geometry, we have implemented the method in the Parallel Deterministic Transport code being developed at Texas A & M University. We discuss the importance of the thick diffusion limit for radiative-transfer problems, and perform a thick diffusion-limit analysis on our discretized system for both geometries. This analysis predicts that the PWLD method will perform well in this limit for many problems of physical interest with arbitrary polygonal and polyhedral cells. Finally, we run a series of test problems to determine some useful properties of the method and verify the results of our thick diffusion limit analysis. Finally, we test our method on a variety of test problems and show that it compares favorably to existing methods. With these test problems, we also show that our method performs well in the thick diffusion limit as predicted by our analysis. Based on PWLD's solid finite-element foundation, the desirable properties it shows under analysis, and the excellent performance it demonstrates on test problems even with highly distorted spatial grids, we conclude that it is an excellent candidate for radiativetransfer problems that need a robust method that performs well in thick diffusive problems or on distorted grids.

The Piecewise Linear Discontinuous Finite Element Method Applied to the RZ and XYZ Transport Equations

The Piecewise Linear Discontinuous Finite Element Method Applied to the RZ and XYZ Transport Equations PDF Author: Teresa S Bailey
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
In this dissertation we discuss the development, implementation, analysis and testing of the Piecewise Linear Discontinuous Finite Element Method (PWLD) applied to the particle transport equation in two-dimensional cylindrical (RZ) and three-dimensional Cartesian (XYZ) geometries. We have designed this method to be applicable to radiative-transfer problems in radiation-hydrodynamics systems for arbitrary polygonal and polyhedral meshes. For RZ geometry, we have implemented this method in the Capsaicin radiative-transfer code being developed at Los Alamos National Laboratory. In XYZ geometry, we have implemented the method in the Parallel Deterministic Transport code being developed at Texas A & M University. We discuss the importance of the thick diffusion limit for radiative-transfer problems, and perform a thick diffusion-limit analysis on our discretized system for both geometries. This analysis predicts that the PWLD method will perform well in this limit for many problems of physical interest with arbitrary polygonal and polyhedral cells. Finally, we run a series of test problems to determine some useful properties of the method and verify the results of our thick diffusion limit analysis. Finally, we test our method on a variety of test problems and show that it compares favorably to existing methods. With these test problems, we also show that our method performs well in the thick diffusion limit as predicted by our analysis. Based on PWLD's solid finite-element foundation, the desirable properties it shows under analysis, and the excellent performance it demonstrates on test problems even with highly distorted spatial grids, we conclude that it is an excellent candidate for radiativetransfer problems that need a robust method that performs well in thick diffusive problems or on distorted grids.

A Piecewise Linear Discontinuous Finite Element Spatial Discretization of the Transport Equation in 2D Cylindrical Geometry

A Piecewise Linear Discontinuous Finite Element Spatial Discretization of the Transport Equation in 2D Cylindrical Geometry PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 16

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Book Description
We present a new spatial discretization of the discrete-ordinates transport equation in two-dimensional cylindrical (RZ) geometry for arbitrary polygonal meshes. This discretization is a discontinuous finite element method that utilizes the piecewise linear basis functions developed by Stone and Adams. We describe an asymptotic analysis that shows this method to be accurate for many problems in the thick diffusion limit on arbitrary polygons, allowing this method to be applied to radiative transfer problems with these types of meshes. We also present numerical results for multiple problems on quadrilateral grids and compare these results to the well-known bi-linear discontinuous finite element method.

Finite Element Methods and Their Applications

Finite Element Methods and Their Applications PDF Author: Zhangxin Chen
Publisher: Springer Science & Business Media
ISBN: 3540240780
Category : Science
Languages : en
Pages : 415

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Book Description
Introduce every concept in the simplest setting and to maintain a level of treatment that is as rigorous as possible without being unnecessarily abstract. Contains unique recent developments of various finite elements such as nonconforming, mixed, discontinuous, characteristic, and adaptive finite elements, along with their applications. Describes unique recent applications of finite element methods to important fields such as multiphase flows in porous media and semiconductor modelling. Treats the three major types of partial differential equations, i.e., elliptic, parabolic, and hyperbolic equations.

Understanding and Implementing the Finite Element Method

Understanding and Implementing the Finite Element Method PDF Author: Mark S. Gockenbach
Publisher: SIAM
ISBN: 9780898717846
Category : Mathematics
Languages : en
Pages : 364

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Book Description
Understanding and Implementing the Finite Element Method Mark S. Gockenbach "Upon completion of this book a student or researcher would be well prepared to employ finite elements for an application problem or proceed to the cutting edge of research in finite element methods. The accuracy and the thoroughness of the book are excellent." --Anthony Kearsley, research mathematician, National Institute of Standards and Technology The infinite element method is the most powerful general-purpose technique for computing accurate solutions to partial differential equations. Understanding and Implementing the Finite Element Method is essential reading for those interested in understanding both the theory and the implementation of the finite element method for equilibrium problems. This book contains a thorough derivation of the finite element equations as well as sections on programming the necessary calculations, solving the finite element equations, and using a posteriori error estimates to produce validated solutions. Accessible introductions to advanced topics, such as multigrid solvers, the hierarchical basis conjugate gradient method, and adaptive mesh generation, are provided. Each chapter ends with exercises to help readers master these topics.

Galerkin Finite Element Methods for Parabolic Problems

Galerkin Finite Element Methods for Parabolic Problems PDF Author: Vidar Thomée
Publisher: Springer Science & Business Media
ISBN: 9783540632368
Category :
Languages : en
Pages : 320

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Book Description


Recent Developments in Discontinuous Galerkin Finite Element Methods for Partial Differential Equations

Recent Developments in Discontinuous Galerkin Finite Element Methods for Partial Differential Equations PDF Author: Xiaobing Feng
Publisher: Springer
ISBN: 9783319378404
Category : Mathematics
Languages : en
Pages : 0

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Book Description
The field of discontinuous Galerkin finite element methods has attracted considerable recent attention from scholars in the applied sciences and engineering. This volume brings together scholars working in this area, each representing a particular theme or direction of current research. Derived from the 2012 Barrett Lectures at the University of Tennessee, the papers reflect the state of the field today and point toward possibilities for future inquiry. The longer survey lectures, delivered by Franco Brezzi and Chi-Wang Shu, respectively, focus on theoretical aspects of discontinuous Galerkin methods for elliptic and evolution problems. Other papers apply DG methods to cases involving radiative transport equations, error estimates, and time-discrete higher order ALE functions, among other areas. Combining focused case studies with longer sections of expository discussion, this book will be an indispensable reference for researchers and students working with discontinuous Galerkin finite element methods and its applications.

The Mathematical Foundations of the Finite Element Method with Applications to Partial Differential Equations

The Mathematical Foundations of the Finite Element Method with Applications to Partial Differential Equations PDF Author: A. K. Aziz
Publisher: Academic Press
ISBN: 1483267989
Category : Technology & Engineering
Languages : en
Pages : 814

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Book Description
The Mathematical Foundations of the Finite Element Method with Applications to Partial Differential Equations is a collection of papers presented at the 1972 Symposium by the same title, held at the University of Maryland, Baltimore County Campus. This symposium relates considerable numerical analysis involved in research in both theoretical and practical aspects of the finite element method. This text is organized into three parts encompassing 34 chapters. Part I focuses on the mathematical foundations of the finite element method, including papers on theory of approximation, variational principles, the problems of perturbations, and the eigenvalue problem. Part II covers a large number of important results of both a theoretical and a practical nature. This part discusses the piecewise analytic interpolation and approximation of triangulated polygons; the Patch test for convergence of finite elements; solutions for Dirichlet problems; variational crimes in the field; and superconvergence result for the approximate solution of the heat equation by a collocation method. Part III explores the many practical aspects of finite element method. This book will be of great value to mathematicians, engineers, and physicists.

Finite Element Methods for Particle Transport

Finite Element Methods for Particle Transport PDF Author: Ron Tunstall Ackroyd
Publisher: Taylor & Francis Group
ISBN:
Category : Mathematics
Languages : en
Pages : 776

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Book Description
Focuses on the transport of neutral particles, neutrons and photons, using the finite element method to address practical problems in nuclear power and mineral prospecting. Includes discussions of how the method began and has matured to become a practical tool complementing the stochastic Monte Carlo method, spatial finite elements, examples of calculations, equivalent forms of the Boltzmann equation, neutron streaming in voids, some aspects of discontinuous variational solutions, complementary principles and benchmarking, time-dependent transport, and modelling three-dimensional systems. Double spaced. Annotation copyright by Book News, Inc., Portland, OR

Continuous and Discontinuous Galerkin Finite Element Methods for Stochastic Differential Equations

Continuous and Discontinuous Galerkin Finite Element Methods for Stochastic Differential Equations PDF Author: Bryan P. Johnson
Publisher:
ISBN: 9781321664003
Category : Differential equations
Languages : en
Pages : 122

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Book Description
In this thesis, we develop high order numerical methods for strong solution of Itô stochastic differential equations (SDEs). We first construct an approximate deterministic ODE with a random coefficient on each element using the Wong-Zakai approximation theorem. Since the resulting equation converges to the solution of the corresponding Stratonovich SDE, we apply a transformation to the drift term to obtain an ODE which converges to the solution of the original SDE. The corrected equation is then discretized using the standard continuous and discontinuous finite element methods for deterministic ODEs. Our methods are demonstrated to be strongly convergent, accurate, and computationally efficient. More precisely, numerical evidence demonstrate that our proposed continuous and discontinuous finite element methods, respectively, have strong convergence order of p/2 and p, when p-degree piecewise polynomials are used. Several linear and nonlinear test problems are presented to show the accuracy and effectiveness of the proposed method.

An adaptive discontinuous finite element method for the transport equation

An adaptive discontinuous finite element method for the transport equation PDF Author: Jens Lang
Publisher:
ISBN:
Category :
Languages : de
Pages : 14

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Book Description