ABSTRACT
Sedimentation is the most important phenomenon not only in measuring fundamental characteristics of particles but also in understanding mechanisms of unit operations such as dust and mist collection, classification, and pneumatic transport. This chapter describes the resistance force on a spherical particle moving through a fluid, the Lagrangian Equation of a particle motion, and the sedimentation velocities of particles in various situations. The atmospheric air in the minimum separation between a particle and a plane surface or two particles whose diameters are less than several tens of microns creates the discontinuum. The rate of sedimentation of the particles in a suspension which are well distributed throughout the fluid in a vessel is slower than the velocity given by the Stokes resistance law. The measured rate of sedimentation vc is not a relative velocity between a particle and a fluid in suspension but a settling velocity of the particle relative to a fixed cross section.
