Contents -- Preface -- 1. Propagation of Waves in Ducts -- 1.1 Plane Waves in an Inviscid Stationary Medium -- 1.2 Three-Dimensional Waves in an Inviscid Stationary Medium -- 1.2.1 Rectangular Ducts -- 1.2.2 Circular Ducts -- 1.3 Waves in a Viscous Stationary Medium -- 1.4 Plane Waves in an Inviscid Moving Medium -- 1.5 Three-Dimensional Waves in an Inviscid Moving Medium -- 1.6 One-Dimensional Waves in a Viscous Moving Medium -- 1.7 Waves in Ducts with Compliant Walls (Dissipative Ducts) -- 1.7.1 Rectangular Duct with Locally Reacting Lining -- 1.7.2 Circular Duct with Locally Reacting Lining -- 1.7.3 Rectangular Duct with Bulk Reacting Lining -- 1.7.4 Circular Duct with Bulk Reacting Lining -- 1.8 Three-Dimensional Waves along Elliptical Ducts -- References -- 2. Theory of Acoustic Filters -- 2.1 Units for the Measurement of Sound -- 2.2 Uniform Tube -- 2.3 Radiation Impedance -- 2.4 Reflection Coefficient at an Open End -- 2.5 A Lumped Inertance -- 2.6 A Lumped Compliance -- 2.7 End Correction -- 2.8 Electroacoustic Analogies -- 2.9 Electrical Circuit Representation of an Acoustic System -- 2.10 Acoustical Filter Performance Parameters -- 2.10.1 Insertion Loss, IL -- 2.10.2 Transmission Loss, TL -- 2.10.3 Level Difference, LD -- 2.10.4 Comparison of the Three Performance Parameters -- 2.11 Lumped-Element Representations of a Tube -- 2.12 Simple Area Discontinuities -- 2.13 Gradual Area Changes -- 2.13.1 Conical Tube -- 2.13.2 Exponential Tube -- 2.13.3 Elliptical Tube -- 2.14 Extended-Tube Resonators -- 2.15 Helmholtz Resonator -- 2.16 Concentric Hole-Cavity Resonator -- 2.17 An Illustration of the Classical Method of Filter Evaluation -- 2.18 The Transfer Matrix Method -- 2.18.1 De.nition of Transfer Matrix -- 2.18.2 Transfer Matrix of a Uniform Tube -- 2.18.3 A General Method for Derivation of Transfer Matrix.

2.18.4 Transfer Matrices of Lumped Elements -- 2.18.5 Transfer Matrices of Variable Area Tubes -- 2.18.6 Overall Transfer Matrix of the System -- 2.18.7 Evaluation of TL in Terms of the Four-Pole Parameters -- 2.19 TL of a Simple Expansion Chamber Muffler -- 2.20 An Algebraic Algorithm for Tubular Mufflers -- 2.20.1 Development of the Algorithm -- 2.20.2 Formal Enunciation and Illustration of the Algorithm -- 2.21 Synthesis Criteria for Low-Pass Acoustic Filters -- References -- 3. Flow-Acoustic Analysis of Cascaded-Element Mufflers -- 3.1 The Exhaust Process -- 3.2 Finite Amplitude Wave Effects -- 3.3 Mean Flow and Acoustic Energy Flux -- 3.4 Aeroacoustic State Variables -- 3.5 Aeroacoustic Radiation -- 3.6 Insertion Loss -- 3.7 Transfer Matrices for Tubular Elements -- 3.7.1 Uniform Tube -- 3.7.2 Extended-Tube Elements -- 3.7.3 Simple Area Discontinuities -- 3.7.4 Physical Behavior of Area Discontinuities -- 3.8 Perforated Elements with Two Interacting Ducts -- 3.8.1 Concentric-Tube Resonator -- 3.8.2 Cross-Flow Expansion Element -- 3.8.3 Cross-Flow Contraction Element -- 3.8.4 Some Remarks -- 3.9 Acoustic Impedance of Perforates -- 3.10 Matrizant Approach -- 3.11 Perforated Elements with Three Interacting Ducts -- 3.11.1 Three-Duct Cross-Flow Expansion Chamber Element -- 3.11.2 Three-Duct Reverse Flow Expansion Chamber Element -- 3.12 Other Elements Constituting Cascaded-Element Mufflers -- References -- 4. Flow-Acoustic Analysis of Multiply-Connected Perforated Element Mufflers -- 4.1 Herschel-Quincke Tube Phenomenon -- 4.2 Perforated Element with Several Interacting Ducts -- 4.3 Three-Pass Double-Reversal Muffler -- 4.4 Flow-Reversal End Chambers -- 4.5 Meanflow Lumped Resistance Network Theory -- 4.6 Meanflow Distribution and Back Pressure Estimation -- 4.6.1 A Chamber with Three Interacting Ducts -- 4.6.2 Three-Pass Double-Reversal Chamber.

4.6.3 A Complex Muffler Configuration -- 4.7 Integrated Transfer Matrix Approach -- 4.7.1 A Muffler with Non-Overlapping Perforated Ducts and a Baffle -- 4.7.2 Muffler with Non-Overlapping Perforated Elements, Baffles and Area Discontinuities -- 4.7.3 A Combination Muffler -- References -- 5. Flow-Acoustic Measurements -- 5.1 Impedance of a Passive Subsystem or Termination -- 5.1.1 The Probe-Tube Method -- 5.1.1.1 Evaluation of the Attenuation Constant and Wave Number -- 5.1.1.2 Evaluation of α± and k± -- 5.1.1.3 Evaluation of the Reflection Coefficient

6.10 The Effect of Terminations on the Performance of Dissipative Ducts -- 6.11 Lined Bends -- 6.12 Plenum Chambers -- 6.13 Flow-Generated Noise -- 6.14 Insertion Loss of Parallel Baffle Mufflers -- References -- 7. Three-Dimensional Analysis of Mufflers -- 7.1 Collocation Method for Simple Expansion Chambers -- 7.1.1 Compatibility Conditions at Area Discontinuities -- 7.1.2 Extending the Frequency Range -- 7.1.3 Extension to Other Muffler Configurations -- 7.2 Finite Element Methods for Mufflers -- 7.2.1 A Single Element -- 7.2.2 Variational Formulation of Finite Element Equations -- 7.2.3 The Galerkin Formulation of Finite Element Equations -- 7.2.4 Evaluation of Overall Performance of a Muffler -- 7.2.5 Numerical Computation -- 7.3 Green's Function Method for a Rectangular Cavity -- 7.3.1 Derivation of the Green's Function -- 7.3.2 Derivation of the Velocity Potential -- 7.3.3 Derivation of the Transfer Matrix -- 7.3.4 Validation Against FEM -- 7.4 Green's Function Method for Circular Cylindrical Chambers -- 7.5 Green's Function Method for Elliptical Cylindrical Chambers -- 7.6 Breakout Noise -- 7.6.1 Breakout Noise from Hoses -- 7.6.2 Breakout Noise from Rectangular Ducts -- 7.6.3 Breakout Noise from Elliptical Ducts -- 7.6.4 Breakout Noise from Mufflers -- References -- 8. Design of Mufflers -- 8.1 Requirements of an Engine Exhaust Muffler -- 8.2 Simple Expansion Chamber -- 8.3 Double-Tuned Extended-Tube Expansion Chamber -- 8.4 Tuned Concentric Tube Resonator -- 8.5 Plug Mufflers -- 8.6 Side-Inlet Side-Outlet Mufflers -- 8.7 Designing for Insertion Loss -- 8.8 Three-Pass Double-Reversal Chamber Mufflers -- 8.9 Perforated Baffle Muffler -- 8.10 Forked Dual Muffler System -- 8.11 Design of Short Elliptical and Circular Chambers -- 8.11.1 Short Chamber Con.gurations -- 8.11.2 Theory -- 8.11.3 Results and Discussion.

8.11.4 Acoustical Equivalence of Short Expansion and Flow-reversal End Chambers -- 8.12 Back-Pressure Considerations -- 8.13 Practical Considerations -- 8.14 Design of Mufflers for Ventilation Systems -- 8.15 Active Sound Attenuation -- References -- Appendix A: Bessel Functions and Some of Their Properties -- Appendix B: Entropy Changes in Adiabatic Flows -- B.1 Stagnation Pressure and Entropy -- B.2 Pressure, Density, and Entropy -- Appendix C: Nomenclature -- Index.