Control and manipulation of hydro-elastic waves
Par Antonin Eddi, Physique et mécanique des milieux hétérogènes, ESPCI, Paris
Mardi 5 Février, 14h00, Salle des séminaires (215), 2ème étage, Bâtiment A4N
Wave control has undergone remarkable developments during the past decades as it has applications in many fields from medical imaging to telecommunications or seismology. Most of the wave manipulation techniques proposed so far are based on spatial control of the material properties. Nevertheless, controlling wave propagation in these complex media faces major challenges: their fabrication is out of range due to the spatial and temporal scales involved, the complete knowledge of their properties is extremely though to obtain and direct observations of wave propagation is hard to achieve.
In this presentation, I will introduce a new experimental approach based on the the use of hydro-elastic waves obtained by covering a liquid surface with a thin elastic sheet. By modifying the properties of the membrane we can affect the hydroelastic waves that propagate in this system. We show that if we locally change the thickness of the elastic cover, we can deviate, reflect or focus the waves. We then periodically structure the membrane and thus unveil effects due to he periodicity and/or the nature of the objects that form the regular array. We use an ensemble of circular perforations of which we vary the diameter, the spacing and the pattern, in order to accurately control the propagation of the waves in this artificial crystal.