Experiments on and Simulations of Hollow Cylinders Falling through Quiescent Liquids

Abstract

Quantitative visualization experiments of hollow cylinders falling through a Newtonian liquid were performed. The Archimedes number was in the range 5 to 10⁵, the length/outer diameter ratio of the cylinders was in the range 2.5–10, and the inner/outer diameter ratio was 0–0.85. The definition of the Archimedes number includes the inner and outer cylinder diameters, and it is shown that cylinders with the same Archimedes number having different diameter ratios behave similarly. Particle‐resolved simulations were used to enhance the insight into the fluid flow generated by the settling cylinder. They were also used to assess the flow through a hollow cylinder during settling.