Unit information: Applied Partial Differential Equations 2 in 2013/14

Unit name	Applied Partial Differential Equations 2
Unit code	MATH20402
Credit points	20
Level of study	I/5
Teaching block(s)	Teaching Block 2 (weeks 13 - 24)
Unit director	Professor. Porter
Open unit status	Not open
Pre-requisites	MATH11002, MATH11003 and MATH 20900 (may be taken concurrently)
Co-requisites	None
School/department	School of Mathematics
Faculty	Faculty of Science

Description including Unit Aims

Partial differential equations (PDEs) are differential equations involving partial derivatives of functions of several variables. They are essential for understanding ocean waves, the flow of rivers, the diffusion of pollutants, aerodynamics, the operation of musical instruments, atomic physics, and many other branches of science. This unit will give an introduction to simple PDEs and how they arise in physical problems; it will develop techniques for solving them and understanding the behaviour of the solutions. The unit will develop students' understanding of first year multivariable calculus, Fourier series, and linear algebra. It will introduce the Fourier integral and other methods for solving linear and nonlinear PDEs, and will show how eigenvalues play a central role in applied mathematics. The course emphasises techniques and broad understanding rather than proofs. NOTE: This unit is not available to students who took Differential Equations 2 in 2002-3 or 2001-2.

Aims

To provide the student with the necessary mathematical tools in order to model a wide variety of different physical problems, ranging from waves on strings, the propagation of signals, the diffusion of heat in solids and chemicals in solution, traffic flow and the vibrations of membranes and surfaces.

Syllabus

Part I: Introduction

Review of linear ODE's, Boundary and Initial Conditions. Introduction of Eigenvalues and Eigenfunctions for linear homogeneous problems.

Introduction to PDE's: simple examples of linear and nonlinear. Derivation of the wave equation in 1D and 2D. Derivation of the diffusion equation in 1D and 2/3D. Conservation Laws, flux. Meaning of Boundary conditions.

Part II: PDEs in One Space Dimension

Bounded spatial domain. Boundary conditions, separation of variables, solution of initial-value problem by Fourier series. Sturm-Liouville Theory, eigenfunction expansions and Fourier series.

Infinite spatial domain. Fourier transforms and its properties: derivatives, convolution. Use of contour integration. Introduction and use of the delta "function" as a point source and its Fourier transform. Heaviside functions.

Application of Fourier transforms to solve PDE problems on an infinite domain, including diffusion, wave and Laplace's equation.

Solution of wave equation by separation of variables and Fourier series. Solution of the initial-value problem for an infinite string by Fourier transforms. D'Alembert's solution, interpretation as travelling waves.

Linear and Nonlinear first-order PDE's. Characteristic methods for solution of initial-value problems. Shock waves, expansion fans. Derivation of traffic flow models and solution.

Part III: PDEs in two and three space dimensions.

Time-independent solutions of the diffusion equation. Laplace's equation. Solution in Cartesian and plane polar coordinates by separation of variables and Fourier series.

Separation of variables in cylindrical and spheical coordinates. Eigenfunction expansions. Bessel functions and Legendre functions. Laplace and diffusion equations in cylindrical and spherical coordinates.

Waves in three dimensions, including standing waves in a box and eigenfunctions of the Laplacian.

Relation to Other Units

This unit will be a prerequisite for Mathematical Methods, Fluid Dynamics and other applied mathematics units. It gives applications of the vector calculus and other material in Calculus 2, and includes material (Sturm-Liouville theory) relevant to Ordinary Differential Equations 2, though that is not a prerequisite.

Intended Learning Outcomes

At the end of the course the student should should be able to:

• Understand the physical models and derive PDE's representing diffusion and wave propagation;
• identify appropriate boundary conditions for simple linear PDEs;
• solve linear two-dimensional PDEs on bounded spatial domains by separation of variables using Sturm-Liouville Theory and Fourier series;
• calculate and manipulate Fourier transforms, and use them to solve simple linear PDEs on unbounded spatial domains;
• transform to dimensionless variables and identify dimensionless parameters;
• use the method of characteristics to solve simple linear and nonlinear first order PDEs;
• describe some differences between linear and nonlinear PDEs;
• solve multi-dimensional linear PDE's using separation of variables in a variety of coordinate systems

Transferable Skills:

• Clear thinking; mathematical modelling of physical situations; skill in mathematical manipulation.

Teaching Information

Three lectures and one problems class per week. Regular problem sheets will be distributed which will test the students' understanding of the material through a variety of problems ranging from elementary to difficult. Set questions will be marked promptly and returned with comments. Full solutions of all problems will be distributed.Problems classes will go through examples that compliment both the lectures and the worksheets.

Assessment Information

The final mark for Applied Partial Differential Equations 2 is calculated from a 2½ hour written examination in May/June consisting of FIVE questions. A candidate's FOUR best answers will be used for assessment. Calculators are NOT permitted.

Reading and References

There are many books covering the subject. Recommended texts to compliment the course are:

• S. J. Farlow, Partial Differential Equations for Scientists and Engineers, Dover Publications 1993, QA377 FAR (Queen's Building).
• R. Haberman, Applied Partial Differential Equations, Pearson/Prentice-Hall 2004. QA377 HAB (Queen's Building).

Farlow is written in a straightforward and clear style, and covers most of the course, rather briefly. Haberman has much more detail, and includes more up to date and advanced material beyond the scope of this unit, but would be useful to students planning to take more advanced courses in applied mathematics.