Mode conversion effect on the scattering of elastic spheres near resonance

Presents experimental and theoretical investigations about the effect of mode conversion on the ultrasonic total cross section of polystyrene spheres near the resonance. An ultrasonic continuous-wave was transmitted through a random medium consisting of a suspension of polystyrene spheres (mean diameter 0.589 mm, standard deviation 0.066 mm) in a solution of water and sugar. The average total cross section of the particle distribution was obtained from measurements of the wave intensity attenuation, for frequency ranges of 0.85 to 3.0 MHz and 5.0 to 6.0 MHz, equivalent to ka ranges (k as the wave number and a as the average radius of the particles) of 1.05 to 3.71 and 6.18 to 7.41, respectively. Experimental results of the total cross section presents a resonant behavior, for ka between 1.07 to 1.38, that is demonstrated to be due to propagation of acoustic shear waves inside the particles