Theoretical and experimental study of ultrasonic attenuation in inhomogeneous media: application to grain size and volume fraction measurements

Attenuation in suspensions is studied theoretically and experimentally, in order to evaluate the influence of parameters such as granulometric dispersion of the scatterers, acoustic contrast and volume fraction. As expected, attenuation magnitude appears mainly due to volume fraction while the general behavior of attenuation depends on the density and compressibility contrasts between particles and fluid. It is shown that multiple scattering produces a nonmonotonous behavior of attenuation versus frequency and that attenuation reaches a maximum, the frequency position of which is related to the average and standard deviation of scatterer size. Multiple scattering theories are then fitted to experimental data in order to obtain average grain size.