High-frequency wave propagation in suspensions of elastic particles: Experimental validation of a time domain numerical simulation.

Abstract

Sound propagation in suspensions of elastic particles immersed in a fluid is a difficult problem due to (i) the random distribution of the particles and (ii) possible multiple scattering and mode conversion effects. The ultrasonic propagation in suspensions has mostly been studied in the frequency domain and time domain approaches may also be of interest. Here, two‐dimensional finite difference time domain numerical simulations of ultrasonic propagation in suspensions of polystyrene 6‐μm‐diameter microspheres immersed in water were performed around 50 MHz. The numerical results were compared with the Faran analytical model, leading to a maximum difference of 15%, which constitutes a validation of the numerical approach. Experiments were carried out in transmission and backscattering modes. The attenuation coefficient 50 MHz [α(50)], the ultrasonic velocity (V) and the relative backscattered intensity (IB) were measured for different concentrations (from 2 to 25 mg/ml). Each experimental ultrasonic paramet...