Settling and fluidization of tall cylinders in solid‐liquid suspensions

Abstract

We numerically study how rigid solid cylinders with a length over diameter aspect ratio of 10 settle through suspensions consisting of uniformly sized solid spheres and Newtonian liquid. We identify regimes with preference for horizontal settling and vertical settling of the cylinders dependent on the overall solids volume fraction (in the range of 0-0.58) and the Archimedes number of the cylinders. These insights we use to interpret the behavior of fluidized suspensions consisting of mixtures of spheres and cylinders with an emphasis on cylinder orientation distributions and slip velocities between solids and liquid phase. The three-dimensional and timedependent simulations explicitly resolve the solid-liquid interfaces by applying an immersed boundary method contained in a lattice-Boltzmann flow solver.

Experiments on and Simulations of Hollow Cylinders Falling through Quiescent Liquids

“…Such particle-resolved simulations (PRSs) are a relatively recent development [13], initially used for flow around moving spheres [14]. PRSs of sedimenting nonspherical particles have been reported by Wachs et al [15], and PRSs of fluidization of cylindrical particles by Derksen [16].…”