Sedimentation of two unequal spheres in a square tube at low Reynolds numbers

Abstract

The settling behaviors of two unequal spheres in a square tube at low Reynolds numbers were numerically studied through a three-dimensional lattice Boltzmann method (LBM). Due to the hydrodynamic interaction, a periodic state or a steady state is achieved according to the density ratio between the spheres. In addition, it is seen that the spheres form a staggered stable configuration at the steady state, for which both spheres rotate in the same manner. The effects of the Reynolds number were also examined.