Fundamentals of Acoustic Waves and Applications (Synthesis Lectures on Wave Phenomena in the Physical Sciences)

This book discusses acoustic waves in five chapters. Chapter 1 reviews the general properties of waves. Chapter 2 presents the acoustic waves in fluid and solids, including the wave equations in the respective media. Chapter 3 discusses the propagation of audible acoustic waves in the air. The discussion includes analyses of speech and music we hear in the time and frequency domains. Chapter 4 discusses the propagation of acoustic waves in solids. Unlike in the air, sound waves take complicated forms in solids; they can be both in longitudinal and transverse modes, and mode conversions can occur upon reflection. Although these behaviors make the analysis difficult, we can apply them to engineering problems. Chapter 5 describes the transduction of acoustic signals. It presents acoustic transmitters and sensors along with their operation principles. Finally, Chapter 6 presents several techniques used in engineering. It is also useful to consider applying acoustic and optical techniques to engineering problems. Preface Contents 1 General Discussions of Waves [DELETE] 1.1 Wave as a Movement of an Oscillatory Pattern 1.1.1 Terms to Represent a Wave 1.1.2 Longitudinal and Transverse Waves 1.2 Mathematics of Waves 1.2.1 Wave Function as a Periodic Function of Time and Space 1.2.2 Wave Equations 1.2.3 Wave Solutions References 2 Wave Dynamics 2.1 Oscillations and Waves 2.1.1 Harmonic Oscillations 2.1.2 Equation of Motion of Point Mass-Spring System 2.1.3 Oscillation to Waves 2.1.4 Wave Equations 2.2 Acoustic Wave Equations and Solutions 2.2.1 Acoustic Wave in Air 2.2.2 Longitudinal and Transverse Vibrations in Solid 2.2.3 Decaying Acoustic Wave Equations and Solutions 2.2.4 Nonlinear Wave Equations 2.3 Wave as a Flow of Energy 2.3.1 Acoustic Energy 2.3.2 Intensity of Acoustic Wave 2.4 Acoustic Wave Reflection and Transmission 2.4.1 Laws of Reflection and Refraction 2.4.2 Behavior of Acoustic Waves Near Boundary References 3 Propagation of Acoustic Waves in Air [DELETE] 3.1 Dynamics of Air Particles and Acoustic Wave Equation in Air 3.1.1 Particle Motions in Longitudinal Waves 3.1.2 Wave-Generating Mechanism in Air 3.1.3 Decaying Pressure Waves in Air 3.2 Sound We Hear 3.2.1 Our Ear 3.2.2 Sounds of Speech and Music 3.3 Transmission of Audible Sound Waves References 4 Propagation of Acoustic Waves in Solids [DELETE] 4.1 Acoustic Wave as Solutions to the Equation of Motion 4.1.1 Equation of Motion 4.2 Propagation of Acoustic Waves in Solid Under Various Conditions 4.2.1 Plane Waves in an Elastic Medium 4.2.2 Plane Waves in a Medium with Free Surface 4.2.3 Surface Waves 4.2.4 Waves Propagating in Plates References 5 Electrical-Mechanical Transduction 5.1 General Argument 5.2 Reciprocal Transduction 5.2.1 Electrostatic Transducer 5.2.2 Electrical Governing Equation of Electrostatic Transducer 5.2.3 Mechanical Governing Equation of Electrostatic Transducer 5.2.4 Physics Behind Electrostatic Transducer's Operation 5.3 Anti-reciprocal Transducers 5.3.1 Moving-Coil Transducer References A Direction Cosines B Gradient Operation C Orthogonality of Sine and Cosine Functions D Notes on Standing Waves E Generalized Hooke's Law and Equation of Motion for Isotropic Media E.1 Strain and Stress Matrices E.2 Compliance and Stiffness Matrices E.3 Principal Axes E.4 Isotropic Case E.4.1 Axis Inversion E.4.2 Rotation Around Axis E.5 Expression of Compliance Matrix with Elastic Constants E.6 Equation of Motion References Index