Flow Visualization around Oloid

This paper deals with a visualization around the so-called Oloid. This is a particular shape constructed by two circular disks which are inserted each other by right angle. It is possible to move this like a paddle of a boat. It is known, however, that it is very difficult to have a practical one because of large loading and control of the moving rod. Recently, it has been achieved using recent electronics technique, a new direct- current motor. It is used for a practical stirring machine and said that this is effective for saving energy though the flow phenomena has not been investigated yet. The results of flow visualization with micro bubbles show that the vortex behind the Oloid is a vortex ring. This makes effective mixing with small flow velocity.