The present numerically investigates the axisymmetric flow past a rotating torus in a viscous incompressible fluid. The surface of the torus rotates with constant velocity around its centerline. A numerical model has been developed for the governing equation in the toroidal coordinate system. The rotating boundary of a torus generates inertia in the surrounding fluid. There are two interesting regimes. In one of them, a rotation of torus surface generates a toroidal fluid region which envelopes the torus. In another one a rotation of torus surface generates the jet of fluid expelled from the hole downward. We focus on the hydrodynamics of a torus effected by a rotational rate (α) and the aspect ratios (Ar). The numerical simulations are performed for three aspect ratios, Ar = 2, 3 and 5, where Ar is defined as ratio of torus radius (b) to cross-section radius of torus (a) and the range of rotational rate -4.0 ≤ α ≤ 2.0, where α is defined as ratio of tangential tank-treading motion of torus surface to the uniform far-field velocity.
