1 Institute Jean le Rond d’Alembert Mechanics, Acoustics, Energetics Univ. Paris 6 - UPMC and CNRS, Paris and Saint-Cyr l’École A hundred staff members in five teams : Complex Fluids and Hydrodynamic Instabilities FCIH Reacting Fluids and Turbulence FRT Lutheries, Acoustics, Music LAM Modelling, Propagation and Acoustic Imaging MPIA Mechanics and Engineering of Solids and Structures MISES Director: Stéphane Zaleski UMR 7190

2 Droplet impact on a liquid layer Helical vortices (occurs in helicopter-blade wakes, windmills) Fluid biomechanics: Modeling sleep apnea FCIH: Complex Fluids and Hydrodynamic Instabilities Head: Maurice Rossi Fluid mechanics in complex configurations, instabilities, two-phase flow, granular media. Granular flow

3 Vorticity field arising from radiated acoustic pressure numerical simulation Variability of the spatial distribution of the vorticity field in a 2D forced mixing layer. Numerical simulation. The effect of the forcing amplitude is shown. FRT : Reacting Fluids and Turbulence Head: Pierre Sagaut Large eddy simulation, internal combustion engines, uncertainty propagation. Rapid Compression Device The inset shows chemoluminescence data that track the emission of free radicals in the reacting zone.

4 Use of a time reversal mirror to focus on the harmony table The identification of relevant parameters for the quality of musical instruments (violins, flutes, harpsichords) relies on specific techniques.. Nozzle loudspeaker enclosure These shapes are motivated by the need to minimize the sound distortion by jets and vortices. Sound recording in urban environment Correlating sound and measurement is of particular interest here. LAM : Lutheries, Acoustics, Music Head: Hugues Genevois Acoustical, mechanical, and social science studies of music and sound.

5 Reconstructing the vorticity field in the wake of a delta wing by acoustic tomography Acoustic rays contain information about the media they travel in, here vorticity is reconstructed. Plate with piezolelectric transducers The goal is to limit acoustic radiation using active devices. Wave fronts on the surface of a copper cristal. Comparison of Theory and Experiment. Wavespeeds and wavefronts on the surface of a cristal are predicted and measured. MPIA : Modelling, Propagation and Acoustic Imaging Head: Bernard Collet wave propagation in radom media, nonlinear waves, vibration, underwater imaging, time reversal. Numerical simulation of an acoustic shock wave near a fold caustic.

6 Localisation of micro- stresses in concrete or injected sand. MISES : Mechanics and Engineering of Solids and Structures Head: Sébastien Neukirch damage, rupture, slender elastic bodies, structural optimization. Spontaneous spiraling of slender elastic bodies Ductile fracture Optimisation of composite materials