Ultrasonic propagation in close-packed disordered suspensions

Measurements on two systems (each with porosity φ=0.38) show that the ultrasonic response of fluid saturated granular composites is not easily predicted in terms of the acoustic properties of the individual constituents. In particular, systems comprised of unconsolidated glass and Plexiglas grains exhibit anomolous behavior in both the low and high frequency regimes. We find, however, that a satisfactory description of these composites can be developed using the same multiple scattering techniques employed in the analysis of electronic states in liquid and amorphous metals.