Acoustic wave spectroscopy inside a reverberant media with moving scatterers

Abstract

In this work, we present an original method in order to measure static and dynamic parameters of moving scatterers confined inside a strong reverberant cavity. In such media, wave propagation is very complex due to multiple scattering and multiple reflections. In a previous article (de Rosny et al., J. Acoust. Soc. Am. (2001)], we have shown that the number or the elastic cross section of moving scatterers, like a school of fish in an aquarium, are deduced from the pressure field averaged over different and independent positions of the scatterers cloud. In this talk, we present an extension of this work which also takes into account the scatterer’s dynamics, e.g., mean speed. Basically, the idea is to relate the correlation of the pressure field to the scatterer’s motion. A DAWS-like (Diffusive Acoustic Wave Spectroscopy) theory based on a statistical approach of this system is presented. The theory is compared with experimental data obtained with scatterers whose motion and elastic cross section are known. Finally this method is applied in order to survey the dynamic behavior of a school of fish inside an aquarium under some environmental modifications as luminosity or temperature.