Hejie Lin

Turgay Bengisu

Zissimos P. Mourelatos

Lecture Notes on Acoustics and Noise Control

Lecture Notes on Acoustics and Noise Control

Hejie Lin • Turgay Bengisu

Zissimos P. Mourelatos

Lecture Notes on Acoustics and Noise Control

ISBN 978-3-030-88212-9 ISBN 978-3-030-88213-6 (eBook) https://doi.org/10.1007/978-3-030-88213-6

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Two significant projects in numerical analysis of sound propagation are included in this course. The first project revolves around numerically calculating the sound pressure induced by a vibrating plate. This project requires students to understand the formulations for acoustic point sources and apply them to the real-world situations. The first project concludes the fundamental acoustics theory in the first half of the course (Chaps 1, 2, 3, 4, 5 and 6). The second project requires numerical calculation of the sound power transmission in pipes. This project requires students to understand the formula for power transmission in pipes as filters and apply them to real-world problems. The second project concludes the filter design in the second half of the course (Chaps. 7, 8, 9, 10, 11 and 12).

Prerequisites

Students should have a basic knowledge of practical experience with calculus and differential equations.

The Big Picture

The first half of this book covers the fundamentals of acoustic wave formulations. Chapter 1 reviews complex numbers and introduces four equivalent forms of complex numbers for harmonic waves. Understanding these four equivalent forms of complex numbers is crucial for understanding the mathematical formulations of acoustics and noise control. Chapters 2, 3, and 4 derive and solve the plane acoustic wave equation. Chapters 5 and 6 derive and solve the spherical wave equation. At the end of Chap. 6, Project #1 is included to reinforce and consolidate the learning from Chaps. 1 to 6 (the first half of the course). This project requires students to numerically calculate sound pressure using the point source formulation obtained in Chap. 6.

The second half of this book covers applications of acoustics in the field of noise control. Chapters 7 and 8 explain and formulate the sound resonance in rectangular cavities and sound propagation in wave guides. Chapter 9 introduces the concept of weighted sound pressure levels. Chapter 10 introduces the basic formulations for noise control of room acoustics. Chapters 11 and 12 cover the theory of three basic acoustic filters: the high-pass filter, the low-pass filter, and the band-stop (Helmholtz) filters.

At the end of Chapter 11, Project 2A is included to numerically calculate sound power transmission in pipelines using the formulas developed in this chapter. At the end of Chapter 12, Project 2B is included to model low-pass filters, high-pass filters, and band-stop filters as pipes with side branches. In this project, sound power transmission of filters will be calculated.