Numerical studies of the flow past a rotating sphere at \textit{Re} = 500

The flow past a rotating sphere is of interest in many engineering applications. A number of numerical studies have been performed to investigate the flow past a streamwise and transversely rotating sphere in the laminar flow regime (\textit{Re} $\le $ 300, where \textit{Re} is the Reynolds number based on freestream velocity, $U_{\infty }$, and sphere diameter, $d)$. In order to extend the understanding of a sphere's trajectory due to the rotating motion of the sphere, the flow past a rotating sphere is investigated for \textit{Re} = 500. This Reynolds number sits in the unsteady asymmetric regime for a stationary sphere. The non-dimensional rotation rates, 0 $\le \quad \Omega ^{\ast}$ $\le $ 1, are considered. The sphere rotation axis is orientated in two of the principle axis directions, namely streamwise and transverse directions. The effect of the rotation axis and $\Omega ^{\ast}$ on the flow structures and the aerodynamic forces of a rotating sphere will be presented.