Objectives
Have the basic knowledge in acoustics and wave propagation in fluids
Keywords
Acoustics, Sound, Noise, Waves, Dispersion relation, Phase and group velocities
Programme
I Acoustics
- Sound waves as linear perturbations of fluid mechanics equations.
- Sourd perception : deciBels, weighting curves.
- Wave propagation equations ; acoustic energy and intensity. Description in the frequency domain ; Helmholtz equation.
- Plane and spherical waves ; characteristic impedance; near field, far field.
- Reflection of waves at interfaces. Notion of impedance,
- Sound radiation from vibrating structures. Integral formulation.
II Waves in fluids
- Dispersive waves with the example of surface gravity waves,
- Propagation of a wave packet, phase velocity, group velocity, dispersion relation.
- High-frequency approximation and ray-tracing.
TP on acoustic materials. BE on the design of a muffler.
Learning Outcomes
- Basic calculations in acoustics (sound pressure levels, source power, dB, ...)
- Kknowledge of elementary sources (plane and spherical)
- Know the basics about the dB scale, the characterization of noise pollution and its perception
- Master the general techniques to analyse linear propagation of waves in fluids: dispersion relation, high-frequency approximation
Assesment
Final mark = 0.6 Exam + 0.4 (BE + TP) BE = report on the work done on the muffler design TP = report on the TP on acoustic materials Exam = written exam of 2 h