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Towards the control of acoustic waves using Sonic Crystals

"Towards the control of acoustic waves using Sonic Crystals"

par
CV. Romero-Garcia Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas
L.M. Garcia-Raffi Instituto Universitario de Matematica Pura y Aplicada, Universidad Politecnica de Valencia

le Jeudi 21 Avril à 14h00 salle de conférence du 4ème étage

Phononic Crystals are periodic distribution of elastic scatterers in an elastic host medium. In the case in which one of the media is a fluid these systems are known as Sonic Crystals (SCs). Both systems are the analogous of Photonic Crystals for the case of elastic and acoustic waves respectively. The control of the acoustical properties of the SCs needs the study of the distribution of the scatterers in the structure as well as of the intrinsic acoustical properties of the scatterers. In this talk we present an analysis of the distribution of the scatterers in SCs and several possibilities to improve the acoustical properties of the SC using scatterers with absorbent and/or resonant properties. Both procedures, working together or independently, provide real possibilities to control the propagation of acoustic waves. From the theoretical point of view, the wave propagation through periodic and quasiperiodic structures has been analysed by means of the multiple scattering theory, the plane wave expansion and the finite elements method. A novel extension of the plane wave expansion to obtain the complex relation dispersion for SC allows us to identify new modes in the structure with evanescent behaviour. This technique gives a more accurate picture of the propagation properties of SC. The interplay between the optimized structures of scatterers and the intrinsic properties of the scatterers themselves is applied to generate devices that present wide ranges of attenuated frequencies.

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