Sound Propagation: An Impedance Based Approach / Edition 1

by Yang-Hann Kim

Overview

In Sound Propagation: An Impedance Based Approach, Professor Yang-Hann Kim introduces acoustics and sound fields by using the concept of impedance. Kim starts with vibrations and waves, demonstrating how vibration can be envisaged as a kind of wave, mathematically and physically. One-dimensional waves are used to convey the fundamental concepts. Readers can then understand wave propagation in terms of characteristic and driving point impedance. The essential measures for acoustic waves, such as dB scale, octave scale, acoustic pressure, energy, and intensity, are explained. These measures are all realized by one-dimensional examples, which provide mathematically simplest but clear enough physical insights.

Kim then moves on to explaining waves on a flat surface of discontinuity, demonstrating how propagation characteristics of waves change in space when there is a distributed impedance mismatch. Next is a chapter on radiation, scattering, and diffraction, where Kim shows how these topics can be explained in a unified way, by seeing the changes of waves due to spatially distributed impedance. Lastly, Kim covers sound in closed space, which is considered to be a space that is surrounded by spatially distributed impedance, and introduces two spaces: acoustically large and small space. The bulk of the book is concerned with introducing core fundamental concepts, but the appendices are included as the essentials as well to cover other important topics to extend learning.

• Offers a less mathematically-intensive means to understand the subject matter
• Provides an excellent launching point for more advanced study or for review of the basics
• Based on classroom tested materials developed over the course of two decades
• Companion site for readers, containing animations and MATLAB code downloads
• Videos and impedance data available from the author's website
• Presentation slides available for instructor use

Sound Propagation is geared towards graduate students and advanced undergraduates in acoustics, audio engineering, and noise control engineering. Practicing engineers and researchers in audio engineering and noise control, or students in engineering and physics disciplines, who want to gain an understanding of sound and vibration concepts, will also find the book to be a helpful resource.

Product Details

ISBN-13:	9780470825839
Publisher:	Wiley
Publication date:	10/04/2010
Pages:	416
Product dimensions:	6.70(w) x 9.80(h) x 1.00(d)

About the Author

Yang-Hann Kim is a Professor of Mechanical Engineering at Korea Advanced Institute of Science and Engineering (KAIST), where he is also Director of the Center for Noise and Vibration Control (NOVIC). He has been teaching acoustics at undergraduate and graduate levels for more than 20 years. Kim's research interests include sound visualization, active noise/vibration control, sound focusing, structural acoustics and duct acoustics. He has won numerous awards, including the Excellence Award in Technology Teaching from Ministry of Industrial Development, Second Place Award at the Gallery of Acoustics during the 132nd meeting of the ASA, and other awards at KAIST and from Korean acoustical societies. He is an active with various journals and societies, having served on the editorial board of the Journal of Sound and Vibration for 11 years and continuing to serve on the Editorial Board as the Handling editor of the Journal of Mechanical Systems and Signal Processing. Kim holds a B.S in Naval Architecture and Marine Engineering from Seoul National University and a PhD in Mechanical Engineering from MIT.

Table of Contents

Preface xi

Acknowledgments xv

1 Vibration and Waves 1

1.1 Introduction/Study Objectives 1

1.2 From String Vibration to Wave 1

1.3 One-dimensional Wave Equation 7

1.4 Specific Impedance (Reflection and Transmission) 10

1.5 The Governing Equation of a String 14

1.6 Forced Response of a String: Driving Point Impedance 17

1.7 Wave Energy Propagation along a String 22

1.8 Chapter Summary 25

1.9 Essentials of Vibration and Waves 25

1.9.1 Single- and Two-degree of Freedom Vibration Systems 25

1.9.2 Fourier Series and Fourier Integral 34

1.9.3 Wave Phenomena of Bar, Beam, Membrane, and Plate 36

Exercises 59

2 Acoustic Wave Equation and Its Basic Physical Measures 69

2.1 Introduction/Study Objectives 69

2.2 One-dimensional Acoustic Wave Equation 69

2.3 Acoustic Intensity and Energy 77

2.4 The Units of Sound 85

2.5 Analysis Methods of Linear Acoustic Wave Equation 96

2.6 Solutions of the Wave Equation 103

2.7 Chapter Summary 110

2.8 Essentials of Wave Equations and Basic Physical Measures 110

2.8.1 Three-dimensional Acoustic Wave Equation 110

2.8.2 Velocity Potential Function 116

2.8.3 Complex Intensity 116

2.8.4 Singular Sources 118

Exercises 125

3 Waves on a Flat Surface of Discontinuity 129

3.1 Introduction/Study Objectives 129

3.2 Normal Incidence on a Flat Surface of Discontinuity 129

3.3 The Mass Law (Reflection and Transmission due to a Limp Wall) 134

3.4 Transmission Loss at a Partition 140

3.5 Oblique Incidence (Snell's Law) 144

3.6 Transmission and Reflection of an Infinite Plate 149

3.7 The Reflection and Transmission of a Finite Structure 153

3.8 Chapter Summary 156

3.9 Essentials of Sound Waves on a Flat Surface of Discontinuity 156

3.9.1 Locally Reacting Surface 156

3.9.2 Transmission Loss by a Partition 159

3.9.3 Transmission and Reflection in Layers 159

3.9.4 Snell's Law When the Incidence Angle is Larger than the Critical Angle 168

3.9.5 Transmission Coefficient of a Finite Plate 169

Exercises 172

4 Radiation, Scattering, and Diffraction 177

4.1 Introduction/Study Objectives 177

4.2 Radiation of a Breathing Sphere and a Trembling Sphere 178

4.3 Radiation from a Baffled Piston 188

4.4 Radiation from a Finite Vibrating Plate 196

4.5 Diffraction and Scattering 201

4.6 Chapter Summary 213

4.7 Essentials of Radiation, Scattering, and Diffraction 214

4.7.1 Definitions of Physical Quantities Representing Directivity 214

4.7.2 The Radiated Sound Field from an Infinitely Baffled Circular Piston 217

4.7.3 Sound Field at an Arbitrary Position Radiated by an Infinitely Baffled Circular Piston 218

4.7.4 Understanding Radiation, Scattering, and Diffraction Using the Kirchhoff-Helmholtz Integral Equation 219

4.7.5 Scattered Sound Field Using the Rayleigh Integral Equation 236

4.7.6 Theoretical Approach to Diffraction Phenomenon 237

Exercises 265

5 Acoustics in a Closed Space 273

5.1 Introduction/Study Objectives 273

5.2 Acoustic Characteristics of a Closed Space 273

5.3 Theory for Acoustically Large Space (Sabine's theory) 274

5.4 Direct and Reverberant Field 282

5.5 Analysis Methods for a Closed Space 287

5.6 Characteristics of Sound in a Small Space 292

5.7 Duct Acoustics 302

5.8 Chapter Summary 312

5.9 Essentials of Acoustics in a Closed Space 313

5.9.1 Methods for Measuring Absorption Coefficient 313

5.9.2 Various Reverberation Time Prediction Formulae 317

5.9.3 Sound Pressure Distribution in Closed 3D Space Using Mode Function 319

5.9.4 Analytic Solution of ID Cavity Interior Field with Any Boundary Condition 320

5.9.5 Helmholtz Resonator Array Panels 323

Exercises 335

Index 339

Editorial Reviews

"These measures are all illustrated by one-dimensionalexamples, which provide mathematically
simplest but clear enough physical insights ... The bulk of thebook is concerned with introducing fundamental concepts, but theappendices cover some additional topics to extend the learning."(Zentralblatt MATH, 2011)

 

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