
Physics 2013
Circular band formation for incompressible viscous fluidrigid particle mixtures in a rotating cylinderDOI: 10.1103/PhysRevE.89.023013 Abstract: In this paper we have investigated a circular band formation of fluidrigid particle mixtures in a fully filled cylinder horizontally rotating about its cylinder axis by direct numerical simulation. These phenomena are modeled by the NavierStokes equations coupled to the EulerNewton equations describing the rigid solid motion of the nonneutrally particles. The formation of circular bands studied in this paper is not resulted by mutual interaction between the particles and the periodic inertial waves in the cylinder axis direction (as suggested in Phys. Rev. E, 72, 021407 (2005)), but due to the interaction of particles. When a circular band is forming, the part of the band formed by the particles moving downward becomes more compact due to the particle interaction strengthened by the downward acceleration from the gravity. The part of a band formed by the particles moving upward is always loosening up due to the slow down of the particle motion by the counter effect of the gravity. To form a compact circular band (not a loosely one), enough particles are needed to interact among themselves continuously through the entire circular band at a rotating rate so that the upward diffusion of particles can be balanced by the compactness process when these particles moving downward.
