This advanced course of acoustics is focused on sources of sound and their propagation. The basics of acoustics, such as the linear acoustic equations and the quantitative evaluation of sound, are briefly presented before going further into the description of sources and their radiation in bounded or unbounded spaces. The sound radiated by vibrating structures and the acoustic propagation in inhomogeneous media are also discussed. The objective of the course is to provide the theoretical background required to approach a complex problem of sound generation and/or radiation. This course also provides a basis for students who might be interested in more specialised sub-domains of acoustics.
I – Equations of linear acoustics (wave equation, acoustic energy, harmonic waves) II – Plane and spherical waves, Boundary conditions, Surface impedance III – Acoustic levels and spectral analysis (Decibels, power spectral density, weightings) IV – Acoustic propagation in ducts (duct modes, cut-off frequency, low frequency models) V – Sources (elementary sources, Green’s function, source distribution) VI – Radiation from vibrating structures (boundary integral equation, Rayleigh integral) VII – Acoustic propagation in inhomogeneous media (geometrical and paraxial approximations) VIII – Further elaborations (thermo-viscous absorption, diffraction by rigid bodies)
Activity contextualised through environmentally sustainable development and social responsibility and/or supported by examples, exercises, applications.
The course presents fundamental elements on the generation and propagation of sound, including noise as a nuisance that can induce a disconfort or even harmful effects on health for long exposures. Part of the lectures is dedicated to accounting to the perception of sound by humans, and the noise generated by a common appliance is measured during a lab session. A special lecture is dedicated to a diagnostic and noise source identification technique: acoustic source localisation.