ABSTRACT
In many treatments of powder in industrial processes, mechanical vibration and sonic energy have been used to increase the efficiency of the operation, and to enhance the transport rates in various industrial operations such as emulsification, size reduction, classification, mixing, drying, and agglomeration. Sound, generally, is radiated by the vibration of a surface, the rapid dilation of fluid medium, and the formation of fluctuating eddies in a fluid. In the instrumentation of a particulate system, impact and frictional sound between particles are important to measure the state variables of the processes. The convection phenomenon in a vibrating powder bed has attracted considerable attention as it is similar to the Rayleigh Bernard or Marangoni convection observed in fluids. In the flow and deformation of a granular bed, successive intermittent slip lines are formed in the bed, and the periodicity of the intermittent shear yields relates to the frictional properties of the bed.
