Julian L. Davis

Mathematics of Wave Propagation (eBook, PDF)

• Format: PDF

Produktbeschreibung

Earthquakes, a plucked string, ocean waves crashing on the beach, the sound waves that allow us to recognize known voices. Waves are everywhere, and the propagation and classical properties of these apparently disparate phenomena can be described by the same mathematical methods: variational calculus, characteristics theory, and caustics. Taking a medium-by-medium approach, Julian Davis explains the mathematics needed to understand wave propagation in inviscid and viscous fluids, elastic solids, viscoelastic solids, and thermoelastic media, including hyperbolic partial differential equations and characteristics theory, which makes possible geometric solutions to nonlinear wave problems. The result is a clear and unified treatment of wave propagation that makes a diverse body of mathematics accessible to engineers, physicists, and applied mathematicians engaged in research on elasticity, aerodynamics, and fluid mechanics.

This book will particularly appeal to those working across specializations and those who seek the truly interdisciplinary understanding necessary to fully grasp waves and their behavior. By proceeding from concrete phenomena (e.g., the Doppler effect, the motion of sinusoidal waves, energy dissipation in viscous fluids, thermal stress) rather than abstract mathematical principles, Davis also creates a one-stop reference that will be prized by students of continuum mechanics and by mathematicians needing information on the physics of waves.

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Produktdetails

• Verlag: University of Pittsburgh Press
• Erscheinungstermin: 12. Januar 2021
• Englisch
• ISBN-13: 9780691223377
• Artikelnr.: 60403452

Autorenporträt

Julian L. Davis is the author of Wave Propagation in Solids and Fluids and Wave Propagation in Electromagnetic Media, in addition to two texts on the dynamics of continuous media. Following many years as a research scientist at the Army Armament Research Laboratory and the Army's Ballistic Research Laboratory, he works as a consultant in the engineering sciences. He has also served as an aerodynamicist in the commercial aircraft industry and taught applied mathematics at the Stevens Institute of Technology.

Inhaltsangabe

Preface xiii
CHAPTER ONE Physics of Propagating Waves 3
Introduction 3
Discrete Wave-Propagating Systems 3
Approximation of Stress Wave Propagation in a Bar by a Finite System of
Mass-Spring Models 4
Limiting Form of a Continuous Bar 5
Wave Equation for a Bar 5
Transverse Oscillations of a String 9
Speed of a Transverse Wave in a Siting 10
Traveling Waves in General 11
Sound Wave Propagation in a Tube 16
Superposition Principle 19
Sinusoidal Waves 19
Interference Phenomena 21
Reflection of Light Waves 25
Reflection of Waves in a String 27
Sound Waves 29
Doppler Effect 33
Dispersion and Group Velocity 36
Problems 37
CHAPTER TWO Partial Differential Equations of Wave Propagation 41
Introduction 41
Types of Partial Differential Equations 41
Geometric Nature of the PDEs of Wave Phenomena 42
Directional Derivatives 42
Cauchy Initial Value Problem 44
Parametric Representation 49
Wave Equation Equivalent to Two First-Order PDEs 51
Characteristic Equations for First-Order PDEs 55
General Treatment of Linear PDEs by Characteristic Theory 57
Another Method of Characteristics for Second-Order PDEs 61
Geometric Interpretation of Quasilinear PDEs 63
Integral Surfaces 65
Nonlinear Case 67
Canonical Form of a Second-Order PDE 70
Riemann's Method of Integration 73
Problems 82
CHAPTER THREE The Wave Equation 85
PART I ONE-DIMENSIONAL WAVE EQUATION 85
Factorization of the Wave Equation and Characteristic Curves 85
Vibrating String as a Combined IV and B V Problem 90
D'Alembert's Solution to the IV Problem 97
Domain of Dependence and Range of Influence 101
Cauchy IV Problem Revisited 102
Solution of Wave Propagation Problems by Laplace Transforms 105
Laplace Transforms 108
Applications to the Wave Equation 111
Nonhomogeneous Wave Equation 116
Wave Propagation through Media with Different Velocities 120
Electrical Transmission Line 122
PART II THE WAVE EQUATION IN TWO AND THREE DIMENSIONS 125
Two-Dimensional Wave Equation 125
Reduced Wave Equation in Two Dimensions 126
The Eigenvalues Must Be Negative 127
Rectangular Membrane 127
Circular Membrane 131
Three-Dimensional Wave Equation 135
Problems 140
CHAPTER FOUR Wave Propagation in Fluids 145
PART I INVISCID FLUIDS 145
Lagrangian Representation of One-Dimensional Compressible Gas Flow 146
Eulerian Representation of a One-Dimensional Gas 149
Solution by the Method of Characteristics: One-Dimensional Compressible Gas
151
Two-Dimensional Steady Flow 157
Bernoulli's Law 159
Method of Characteristics Applied to Two-Dimensional Steady Flow 161
Supersonic Velocity Potential 163
Hodograph Transformation 163
Shock Wave Phenomena 169
PART II VISCOUS FLUIDS 183
Elementary Discussion of Viscosity 183
Conservation Laws 185
Boundary Conditions and Boundary Layer 190
Energy Dissipation in a Viscous Fluid 191
Wave Propagation in a Viscous Fluid 193
Oscillating Body of Arbitrary Shape 196
Similarity Considerations and Dimensionless Parameters; Reynolds' Law 197
Poiseuille Flow 199
Stokes' Flow 201
Oseen Approximation 208
Problems 210
CHAPTER FIVE Stress Waves in Elastic Solids 213
Introduction 213
Fundamentals of Elasticity 214
Equations of Motion for the Stress 223
Navier Equations of Motion for the Displacement 224
Propagation of Plane Elastic Waves 227
General Decomposition of Elastic Waves 228
Characteristic Surfaces for Planar Waves 229
Time-Harmonic Solutions and Reduced Wave Equations 230
Spherically Symmetric Waves 232
Longitudinal Waves in a Bar 234
Curvilinear Orthogonal Coordinates 237
The Navier Equations in Cylindrical Coordinates 239
Radially Symmetric Waves 240
Waves Propagated Over the Surface of an Elastic Body 243
Problems 247
CHAPTER SIX Stress Waves in Viscoelastic Solids 250
Introduction 250
Internal Friction 251
Discrete Viscoelastic Models 252
Continuous Marwell Model 260
Continuous Voigt Model 263
Three-Dimensional VE Constitutive Equations 264
Equations of Motion for a VE Material 265
One-Dimensional Wave Propagation in VE Media 266
Radially Symmetric Waves for a VE Bar 270
Electromechanical Analogy 271
Problems 280
CHAPTER SEVEN Wave Propagation in Thermoelastic Media 282
Introduction 282
Duhamel-Neumann Law 282
Equations of Motion 285
Plane Harmonic Waves 287
Three-Dimensional Thermal Waves; Generalized Navier Equation 293
CHAPTER EIGHT Water Waves 297
Introduction 297
Irrotational, Incompressible, Inviscid Flow; Velocity Potential and
Equipotential Surfaces 297
Euler's Equations 299
Two-Dimensional Fluid Flow 300
Complec Variable Treatment 302
Vortex Motion 309
Small-Amplitude Gravity Waves 311
Water Waves in a Straight Canal 311
Kinematics of the Free Surface 316
Vertical Acceleration 317
Standing Waves 319
Two-Dimensional Waves of Finite Depth 321
Boundary Conditions 322
Formulation of a Typical Surface Wave Problem 324
Example of Instability 325
Approximation Aeories 327
Tidal Waves 337
Problems 342
CHAPTER NINE Variational Methods in Wave Propagation 344
Introduction; Fermat's Principle 344
Calculus of Variations; Euler's Equation 345
Configuration Space 349
Kinetic and Potential Energies 350
Hamilton's Variational Principle 350
Principle of Virtual Work 352
Transformation to Generalized Coordinates 354
Rayleigh's Dissipation Function 357
Hamilton's Equations of Motion 359
Cyclic Coordinates 362
Hamilton-Jacobi Theory 364
Extension of W to 2n Degrees of Freedom 370
H-J Theory and Wave Propagation 372
Quantum Mechanics 376
An Analogy between Geometric Optics and Classical Mechanics 377
Asymptotic Theory of Wave Propagation 380
Appendix: The Principle of Least Action 384
Problems 387
Bibliography 389
Index 391

Rezensionen

An excellent book that covers seemingly diverse wave phenomena in a unified, coherent manner. Students and practicing engineers and physicists will find this book a useful addition to their collections.