Attenuation of sound in concentrated suspensions: Theory and experiments

Ensemble-averaged equations are derived for small-amplitude acoustic wave propagation through non-dilute suspensions. The equations are closed by introducing suspension effective properties such as the compressibility, density, viscoelasticity, heat capacity, and conductivity. These effec-tive properties as a function of frequency, particle volume fraction, and physical properties of the individual phases are estimated using a self-consistent, effective-medium approximation. The the-ory is shown to be in excellent agreement with various rigorous analytical results accounting for multiparticle interactions. The theory is also shown to agree well with the experimental data on concentrated suspensions of small polystyrene particles in water obtained by Allegra and Hawley and for glass particles in water obtained in the present study