The objective of this third edition is the same as in previous two editions: to provide a broad coverage of various mathematical techniques that are widely used for solving and to get analytical solutions to Partial Differential Equations...
moreThe objective of this third edition is the same as in previous two editions: to provide a broad coverage of various mathematical techniques that are widely used for solving and to get analytical solutions to Partial Differential Equations of first and second order, which occur in science and engineering. In fact, while writing this book, I have been guided by a simple teaching philosophy: An ideal textbook should teach the students to solve problems. This book contains hundreds of carefully chosen worked-out examples, which introduce and clarify every new concept. The core material presented in the second edition remains unchanged. I have updated the previous edition by adding new material as suggested by my active colleagues, friends and students. Chapter 1 has been updated by adding new sections on both homogeneous and nonhomogeneous linear PDEs, with constant coefficients, while Chapter 2 has been repeated as such with the only addition that a solution to Helmholtz equation using variables separable method is discussed in detail. In Chapter 3, few models of non-linear PDEs have been introduced. In particular, the exact solution of the IVP for non-linear Burger's equation is obtained using Cole-Hopf function. Chapter 4 has been updated with additional comments and explanations, for better understanding of normal modes of vibrations of a stretched string. Chapters 5-7 remain unchanged. I wish to express my gratitude to various authors, whose works are referred to while writing this book, as listed in the Bibliography. Finally, I would like to thank all my old colleagues, friends and students, whose feedback has helped me to improve over previous two editions. It is also a pleasure to thank the publisher, PHI Learning, for their careful processing of the manuscript both at the editorial and production stages. Any suggestions, remarks and constructive comments for the improvement of text are always welcome. With the remarkable advances made in various branches of science, engineering and technology, today, more than ever before, the study of partial differential equations has become essential. For, to have an in-depth understanding of subjects like fluid dynamics and heat transfer, aerodynamics, elasticity, waves, and electromagnetics, the knowledge of finding solutions to partial differential equations is absolutely necessary. This book on Partial Differential Equations is the outcome of a series of lectures delivered by me, over several years, to the postgraduate students of Applied Mathematics at Anna University, Chennai. It is written mainly to acquaint the reader with various well-known mathematical techniques, namely, the variables separable method, integral transform techniques, and Green's function approach, so as to solve various boundary value problems involving parabolic, elliptic and hyperbolic partial differential equations, which arise in many physical situations. In fact, the Laplace equation, the heat conduction equation and the wave equation have been derived by taking into account certain physical problems. The book has been organized in a logical order and the topics are discussed in a systematic manner. In Chapter 0, partial differential equations of first order are dealt with. In Chapter 1, the classification of second order partial differential equations, and their canonical forms are given. The concept of adjoint operators is introduced and illustrated through examples, and Riemann's method of solving Cauchy's problem described. Chapter 2 deals with elliptic differential equations. Also, basic mathematical tools as well as various properties of harmonic functions are discussed. Further, the Dirichlet and Neumann boundary value problems are solved using variables separable method in cartesian, cylindrical and spherical coordinate systems. Chapter 3 is devoted to a discussion on the solution of boundary value problems describing the parabolic or diffusion equation in various coordinate systems using the variables separable method. Elementary solutions are also given. Besides, the maximum-minimum principle is discussed, and the concept of Dirac delta function is introduced along with a few properties. Chapter 4 provides a detailed study of the wave equation representing the hyperbolic partial differential equation, and gives D'Alembert's solution. In addition, the chapter presents problems like vibrating string, vibration of a circular membrane, and periodic solutions of wave equation, shows the uniqueness of the solutions, and illustrates Duhamel's principle. Chapter 5 introduces the basic concepts in the construction of xi Preface to the First and Second Edition ( , ) 0 . F x y z xy z 1 1 1 2 x C C C § • ¨© ¹ (8) 1 c ξ and 2 c η are families of straight lines parallel to the axes as shown in Fig. 1.1(b). From Eqs. (1.50) and (1.51), we have 2 2 2 2 ( ) *( ) 2 2 2 2 0