Coherent attenuation of acoustic waves by pair-correlated random distribution of scatterers with uniform and Gaussian size distributions

Acoustic wave attenuation due to multiple scattering in a two-phase medium consisting of a fluid with embedded rigid, fluid, or elastic particles of varying sizes is discussed. The formulation, involving the exciting and scattered fields of an incident acoustic plane wave, is based on the T-matrix method. The propagation features of coherent waves in the mixture are described by the dispersion equation which is derived by applying standard statistical approximations to the discrete random medium. Special attention is focused on the pair-correlation function between the scatterers using the self-consistent approximation (SCA) which seems better than the Percus-Yevick approximation (PYA) when the volume fraction becomes significant. Besides deriving low-frequency analytical results for coherent wave speed and attenuation, the dispersion equation has been solved numerically for higher frequencies for particles with uniform and Gaussian size distributions.