Motion of suspended particles in gas flow

Abstract

Suppose we have a moving medium - a liquid or a gas under conditions when the latter can be considered an incompressible liquid. In this medium there are a large number of small particles, which we consider as solid bodies - material points, the position of which we will define by their coordinates, attributing to each particle some small mass and some small volume common to all particles. For definiteness we will assume that all particles have a spherical shape and motion different from the motion of the above-mentioned medium. The mass distribution in the medium will be continuous, while the mass distribution of the particles will be clearly discrete.