Stochastic theory for multiple scattering of ultrasound in particulate media

Abstract

Even though there have been published/used several approaches to modeling the complex phenomenon of multiple scattering, they are either of a semi-empirical nature with severe limitations in size/wavelength range and performance or, albeit having a fundamental flavor, have proven not accurate enough to be employed in broad range/application scientific instruments. Fundamental versus phenomenological approaches are discussed. The METAMODEL™ fundamental multiple-scattering theory is as fundamental as Mie (optics) and ECAH (acoustics) single-scattering theories. Besides its fundamental character, its generic validity resides in having described and calculated the detailed interaction between the scattered fields produced by every particle, treating such an interaction in a statistical sense and leading to generic stochastic field equations where the overlapping of all scattered fields is equally contemplated regardless of their physical nature (viscous-inertial, thermal diffusion, elastic, electromagnetic, etc.). The fundamentals of this theory are described in some mathematical detail. Using the Ultra-SCATTERER™ R & D software tool, predicted as well as experimental data in concentrated suspensions, emulsions, and aerosols (collected with commercially available spectrometers) are presented.