ABSTRACT
Interaction of radiation, or more precisely, electromagnetic waves, with a cloud of particles is significant in many applications such as dust clouds and combustion flames at high temperatures, as well as in thermal insulations using particulate materials at very low temperatures. Propagation of sound waves through a suspension is basically a momentum transfer phenomenon. The response of droplets and particles to electric fields is measured by their mobility. When applied to high temperature systems, the electrical conductivity of a mixture of charged solid particles, electrons, ions, and gas atoms of suspending gas is often a useful quantity. For transparent or partially transparent solid particles, the index of refraction depends on their surface condition. Many of the boundary conditions arising from phase interactions are directly accountable or can be directly extended from general concepts of fluid dynamics. It is opportune to treat a boundary condition which is particular with multiphase flow at this point.
