Waves in Particulate Materials: Beyond Low Frequencies
Speaker: Artur Gower, University of Manchester
Title: Waves in Particulate Materials: Beyond Low Frequencies
Abstract: Particulate materials (powders, composites, emulsions, and gases) are everywhere in nature and industry. However, a quantitative understanding of how waves interact with these materials is still lacking, even for the scalar wave equation. This is primarily due to multiple scattering and complex interference patterns that appear beyond the low frequency regime. To date, the prevailing thought is that a wave will perceive the (ensemble) averaged particulate material as a homogeneous medium, and therefore there will exist only one wave (for the scalar wave equation) that propagates in the medium. Here I will show that this is only true in the low frequency regime. In general, a series of waves emerge from the interference patterns. This realisation leads to a highly accurate method, when compared with numerical benchmarks. This result helps answer long standing problems on modelling wave reflection from particulate materials.