Spatial trapping of acoustic waves in bubbly liquids

The propagation of acoustic waves in fluids containing low-density bubbles is investigated, using a plane wave approach. Band structures, densities of modes and density of energy maps are computed in order to understand the mechanisms responsible for the generation of complete frequency gaps in these three-dimensional structures. The dependence of the band gap on different parameters such as the mass density and the sound velocity for different symmetries is discussed. A large unit cell containing randomly placed bubbles shows, for optimized values of the parameters. a strong level of wave confinement and the appearance of wide gaps. (C) 2001 Elsevier Science B.V. All rights reserved.