logo资料库

Partial Differential Equations with Numerical Methods.pdf

第1页 / 共262页
第2页 / 共262页
第3页 / 共262页
第4页 / 共262页
第5页 / 共262页
第6页 / 共262页
第7页 / 共262页
第8页 / 共262页
资料共262页,剩余部分请下载后查看
Texts in Applied Mathematics 45 Editors J.E. Marsden L. Sirovich S.S. Antman Advisors G. Iooss P. Holmes D. Barkley M. Dellnitz P. Newton
Texts in Applied Mathematics Sirovich: Introduction to Applied Mathematics. 1. 2. Wiggins: Introduction to Applied Nonlinear Dynamical Systems and Chaos. 3. 4. 5. 6. Hale/Koçak: Dynamics and Bifurcations. Chorin/Marsden: A Mathematical Introduction to Fluid Mechanics, Third Edition. Hubbard/West: Differential Equations: A Dynamical Systems Approach: Ordinary Differential Equations. Sontag: Mathematical Control Theory: Deterministic Finite Dimensional Systems, Second Edition. Perko: Differential Equations and Dynamical Systems, Third Edition. Seaborn: Hypergeometric Functions and Their Applications. Pipkin: A Course on Integral Equations. 7. 8. 9. 10. Hoppensteadt/Peskin: Modeling and Simulation in Medicine and the Life Sciences, Second Edition. 11. Braun: Differential Equations and Their Applications, Fourth Edition. 12. Stoer/Bulirsch: Introduction to Numerical Analysis, Third Edition. 13. Renardy/Rogers: An Introduction to Partial Differential Equations. 14. Banks: Growth and Diffusion Phenomena: Mathematical Frameworks and Applications. 15. Brenner/Scott: The Mathematical Theory of Finite Element Methods, Second Edition. 16. Van de Velde: Concurrent Scientific Computing. 17. Marsden/Ratiu: Introduction to Mechanics and Symmetry, Second Edition. 18. Hubbard/West: Differential Equations: A Dynamical Systems Approach: Higher-Dimensional Systems. 19. Kaplan/Glass: Understanding Nonlinear Dynamics. 20. Holmes: Introduction to Perturbation Methods. 21. Curtain/Zwart: An Introduction to Infinite-Dimensional Linear Systems Theory. 22. Thomas: Numerical Partial Differential Equations: Finite Difference Methods. 23. Taylor: Partial Differential Equations: Basic Theory. 24. Merkin: Introduction to the Theory of Stability. 25. Naber: Topology, Geometry, and Gauge Fields: Foundations. 26. Polderman/Willems: Introduction to Mathematical Systems Theory: A Behavioral Approach. 27. Reddy: Introductory Functional Analysis: with Applications to Boundary Value Problems and Finite Elements. 28. Gustafson/Wilcox: Analytical and Computational Methods of Advanced Engineering Mathematics. 29. Tveito/Winther: Introduction to Partial Differential Equations: A Computational Approach. 30. Gasquet/Witomski: Fourier Analysis and Applications: Filtering, Numerical Computation, Wavelets. 31. Brémaud: Markov Chains: Gibbs Fields, Monte Carlo Simulation, and Queues. 32. Durran: Numerical Methods for Wave Equations in Geophysical Fluid Dynamics. 33. Thomas: Numerical Partial Differential Equations: Conservation Laws and Elliptic Equations. (continued after index)
Stig Larsson · Vidar Thomée Partial Differential Equations with Numerical Methods 123
Stig Larsson Vidar Thomée Mathematical Sciences Chalmers University of Technology and University of Gothenburg 412 96 Göteborg Sweden stig@chalmers.se thomee@chalmers.se Series Editors J.E. Marsden Control and Dynamical Systems, 107-81 California Institute of Technology Pasadena, CA 91125 USA marsden@cds.caltech.edu L. Sirovich Laboratory of Applied Mathematics Mt. Sinai School of Medicine Box 1012 New York City, NY 10029-6574 USA lawrence.sirovich@mssm.edu First softcover printing 2009 S.S. Antman Department of Mathematics and Institute for Physical Science and Technology University of Maryland College Park, MD 20742-4015 USA ssa@math.umd.edu ISBN 978-3-540-88705-8 e-ISBN 978-3-540-88706-5 DOI 10.1007/978-3-540-88706-5 Texts in Applied Mathematics ISSN 0939-2475 Library of Congress Control Number: 2008940064 Mathematics Subject Classification (2000): 35-01, 65-01 c 2009, 2003 Springer-Verlag Berlin Heidelberg This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer. Violations are liable to prosecution under the German Copyright Law. The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Coverdesign: WMXDesign GmbH, Heidelberg Printed on acid-free paper 9 8 7 6 5 4 3 2 1 springer.com
Series Preface Mathematics is playing an ever more important role in the physical and biological sciences, provoking a blurring of boundaries between scientific disciplines and a resurgence of interest in the modern as well as the classical techniques of applied mathematics. This renewal of interest, both in re- search and teaching, has led to the establishment of the series Texts in Applied Mathematics (TAM). The development of new courses is a natural consequence of a high level of excitement on the research frontier as newer techniques, such as numeri- cal and symbolic computer systems, dynamical systems, and chaos, mix with and reinforce the traditional methods of applied mathematics. Thus, the purpose of this textbook series is to meet the current and future needs of these advances and to encourage the teaching of new courses. TAM will publish textbooks suitable for use in advanced undergraduate and beginning graduate courses, and will complement the Applied Mathe- matical Sciences (AMS) series, which will focus on advanced textbooks and research-level monographs. Pasadena, California New York, New York College Park, Maryland J.E. Marsden L. Sirovich S.S. Antman
Preface Our purpose in this book is to give an elementary, relatively short, and hope- fully readable account of the basic types of linear partial differential equations and their properties, together with the most commonly used methods for their numerical solution. Our approach is to integrate the mathematical analysis of the differential equations with the corresponding numerical analysis. For the mathematician interested in partial differential equations or the person using such equations in the modelling of physical problems, it is important to realize that numerical methods are normally needed to find actual values of the solutions, and for the numerical analyst it is essential to be aware that numerical methods can only be designed, analyzed, and understood with suf- ficient knowledge of the theory of the differential equations, using discrete analogues of properties of these. In our presentation we study the three major types of linear partial differ- ential equations, namely elliptic, parabolic, and hyperbolic equations, and for each of these types of equations the text contains three chapters. In the first of these we introduce basic mathematical properties of the differential equa- tion, and discuss existence, uniqueness, stability, and regularity of solutions of the various boundary value problems, and the remaining two chapters are devoted to the most important and widely used classes of numerical methods, namely finite difference methods and finite element methods. Historically, finite difference methods were the first to be developed and applied. These are normally defined by looking for an approximate solution on a uniform mesh of points and by replacing the derivatives in the differential equation by difference quotients at the mesh-points. Finite element methods are based instead on variational formulations of the differential equations and determine approximate solutions that are piecewise polynomials on some par- tition of the domain under consideration. The former method is somewhat restricted by the difficulty of adapting the mesh to a general domain whereas the latter is more naturally suited for a general geometry. Finite element methods have become most popular for elliptic and also for parabolic prob- lems, whereas for hyperbolic equations the finite difference method continues to dominate. In spite of the somewhat different philosophy underlying the two classes it is more reasonable in our view to consider the latter as further
VIII Preface developments of the former rather than as competitors, and we feel that the practitioner of differential equations should be familiar with both. To make the presentation more easily accessible, the elliptic chapters are preceded by a chapter about the two-point boundary value problem for a second order ordinary differential equation, and those on parabolic and hy- perbolic evolution equations by a short chapter about the initial value prob- lem for a system of ordinary differential equations. We also include a chapter about eigenvalue problems and eigenfunction expansion, which is an impor- tant tool in the analysis of partial differential equations. There we also give some simple examples of numerical solution of eigenvalue problems. The last chapter provides a short survey of other classes of numerical methods of importance, namely collocation methods, finite volume methods, spectral methods, and boundary element methods. The presentation does not presume a deep knowledge of mathematical and functional analysis. In an appendix we collect some of the basic material that we need in these areas, mostly without proofs, such as elements of abstract linear spaces and function spaces, in particular Sobolev spaces, together with basic facts about Fourier transforms. In the implementation of numerical methods it will normally be necessary to solve large systems of linear algebraic equations, and these generally have to be solved by iterative methods. In a second appendix we therefore include an orientation about such methods. Our purpose has thus been to cover a rather wide variety of topics, notions, and ideas, rather than to expound on the most general and far-reaching results or to go deeply into any one type of application. In the problem sections, which end the various chapters, we sometimes ask the reader to prove some results which are only stated in the text, and also to further develop some of the ideas presented. In some problems we propose testing some of the numerical methods on the computer, assuming that Matlab or some similar software is available. At the end of the book we list a number of standard references where more material and more detail can be found, including issues concerned with implementation of the numerical methods. This book has developed from courses that we have given over a rather long period of time at Chalmers University of Technology and G¨oteborg Uni- versity originally for third year engineering students but later also in begin- ning graduate courses for applied mathematics students. We would like to thank the many students in these courses for the opportunities for us to test our ideas. G¨oteborg, January, 2003 Stig Larsson Vidar Thom´ee In the second printing 2005 we have corrected several misprints and minor SL & VT inadequacies, and added a few problems.
Contents 1 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2 Notation and Mathematical Preliminaries . . . . . . . . . . . . . . . . . . 1.3 Physical Derivation of the Heat Equation . . . . . . . . . . . . . . . . . . 7 1.4 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2 A Two-Point Boundary Value Problem . . . . . . . . . . . . . . . . . . . 15 2.1 The Maximum Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.2 Green’s Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2.3 Variational Formulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2.4 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 3 Elliptic Equations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3.1 Preliminaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3.2 A Maximum Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 3.3 Dirichlet’s Problem for a Disc. Poisson’s Integral . . . . . . . . . . . 28 3.4 Fundamental Solutions. Green’s Function . . . . . . . . . . . . . . . . . . 30 3.5 Variational Formulation of the Dirichlet Problem . . . . . . . . . . . 32 3.6 A Neumann Problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 3.7 Regularity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 3.8 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 4 Finite Difference Methods for Elliptic Equations . . . . . . . . . . 43 4.1 A Two-Point Boundary Value Problem . . . . . . . . . . . . . . . . . . . . 43 4.2 Poisson’s Equation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 4.3 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 5 Finite Element Methods for Elliptic Equations . . . . . . . . . . . . 51 5.1 A Two-Point Boundary Value Problem . . . . . . . . . . . . . . . . . . . . 51 5.2 A Model Problem in the Plane . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 5.3 Some Facts from Approximation Theory . . . . . . . . . . . . . . . . . . . 60 5.4 Error Estimates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 5.5 An A Posteriori Error Estimate . . . . . . . . . . . . . . . . . . . . . . . . . . 66 5.6 Numerical Integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 5.7 A Mixed Finite Element Method . . . . . . . . . . . . . . . . . . . . . . . . . 71 5.8 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
分享到:
收藏