Study on the behavior of a light sphere rising in a square tube using the lattice Boltzmann method

Abstract

In this study the motion of a light sphere under gravity in a square tube was numerically investigated through a three-dimensional lattice Boltzmann method. The width of the square tube is fixed at five times the diameter of the sphere. Simulations were carried out in the Reynolds number range of 140 to 200. Three types of behavior of the rising sphere behavior were revealed, namely the steady state, periodic state and chaotic state. In particular, the sphere exhibits a spiral path in the periodic regime. The effects of the Reynolds number on the oscillations of the sphere were also examined.