Interaction between a vortex ring and a rigid sphere

The vortex distortion effect on the flow arising from the interaction between a vortex ring and a rigid sphere was studied for three-dimensional incompressible flow. The vorticity field was represented by a concentrated finite core along the vortex filament described by a parabolic curve function. The trajectories of the centroid of vorticity were obtained to study motion of vortex filament. With small changes of the vertical separation of the vortex ring and rigid sphere, three different interacting patterns were observed. The instantaneous forces acting on the sphere were obtained by Bernoulli equation. The unsteady pressure term calculated by potential based panel method, contributed to the unsteady lift and drag forces during interactions.