Experiments and simulations of settling cylinders over a wide range of Archimedes numbers

Quantitative visualization experiments and particle-resolved simulations of rigid cylindrical particles settling in a Newtonian liquid have been conducted. By varying the viscosity of the liquid – a glycerol-water mixture – as well as the density of the cylinders we were able to cover an Archimedes number range that spans almost 6 orders of magnitude in the experiments. The length over diameter aspect ratio of the cylinders ranged from 2.5 to 20.
Cylinders were released vertically and rotated to a stable horizontal orientation in most of the lower viscosity solutions. The time required for reaching a horizontal orientation, as well as the Reynolds number at that stage scale with the Archimedes number and only weakly depend on the aspect ratio. Particle-resolved numerical simulations based on the lattice-Boltzmann
method complement the experimental study and illustrate the relevance of the experimental data as a benchmark for numerical approaches to solid-liquid flow with non-spherical particles.