Acoustics and Waves in Fluids

Mechanical waves, like sound or ocean waves, are ubiquitous in our daily lives. They span a wide range of scales, from the vast planetary movements that affect weather patterns to the microscopic scales of ultrasound used in cancer treatment. This course aims to provide basic concepts on mechanical waves in fluids, with a particular focus on acoustic waves. It covers the primary phenomena affecting their propagation, such as reflection, refraction, diffraction, and attenuation. Furthermore, it presents fundamental techniques for studying wave propagation in homogeneous and inhomogeneous media, such as ray theory.

1. Introduction to wave propagation. Dispersion, phase velocity, group velocity.
2. Equations of continuum mechanics, linearization.
3. Acoustic waves in homogeneous media: plane and spherical waves, reflection and transmission, diffusion, diffraction, attenuation.
4. Acoustic waves in inhomogeneous media (atmosphere, ocean), rays.
5. Internal gravity waves and surface waves (water waves, ripples). Lab: calculation of the speed of sound in air and water, propagation of spherical waves, Kundt's tube.