GEOMETRIC AND DYNAMIC SIMILARITY IN PARTICLE MIXING

Detailed studies have been made of the displacement of tracer, particles in a granular material over a long horizontal blade that is moving relative to the bed. Three different sized species of the same material were used. Initial and final coordinate positions were determined, and the results for all the sizes can be very satisfactorily correlated in dimensionless form. Experiments have thus been performed in which geometric and dynamic similarity exist. This is particularly encouraging for at least two prominent mixing mechanisms are certainly present, convective and surface mixing. The horizontal movement in a particular material is determined by the depth considered, the blade height, the blade immersion, the relative velocity of the bed to the blade and, by inference, the acceleration due to gravity. The vertical movement, the standard deviation of the horizontal movement and the standard deviation of the vertical movement all depend, in addition to the parameters already mentioned, upon the particle diameter. © 1969.