Particle dynamics and granular temperatures in dense fluidized beds as revealed by diffusing wave spectroscopy

Diffusing wave spectroscopy (DWS) can be used to elucidate the fundamentals of particle motion in dynamic dense granular media and the associated mean of the square of the particle velocity fluctuations about the mean flow velocity, which is related directly to the so-called ‘granular temperature’ that underpins many theories for dynamic granular processes. In this paper, we provide an overview of DWS and, by drawing on our previous and new work, demonstrate its application to various fluidized bed (FB) configurations.