This course provides an introduction to Acoustics. The focus will be on phenomena that are relevant for industrial and transport applications in the contexts of noise pollution and mechanical fatigue due to acoustic-structure interactions. It should be noted that the lecture focuses on the derivation and interpretation of analytical expression to explain various acoustic phenomena.
This course is proposed for Master and PhD students interested in getting knowledge in acoustics. Students will be able to understand, describe analytically and quantify sound generation, absorption and propagation in configurations that are relevant for practical industrial applications (for example in aeronautics, automotive industry or power plants).
First, orders of magnitudes characterizing sound propagation are reviewed and the constitutive equations for acoustics are derived. Then the different types of sources (monopole/dipole/quadrupole, punctual, non-compact) are introduced and linked to the noise generated by turbulent flows, coherent vortical structures or fluctuating heat release. The scattering of sound by rigid bodies is given in basic configurations. Analytical, experimental and numerical methods used to analyze sound in ducts and rooms are presented (Green functions, Galerkin expansions, Helmholtz solvers). Modeling strategies to predict self-sustained acoustic oscillations driven by reacting and non-reacting flows are presented. Finally, guidelines to design active and passive control systems are given.