Visualization of Vortical Flows in Flat Scull

Abstract

Artistic swimming, which is also known as ‘synchronised swimming’, uses an underwater upper limb motion called sculling. We focused on the force generated by a hand motion called a flat scull. The flat scull movements produced the vortical flow and it is presumed that the synchronised swimmers utilize the unsteady fluid forces obtained by this vortex for raising the body to above the surface of the water. In the flat scull, the hand changes its velocity and angle to the flow during the motion. Furthermore, it is necessary to consider a three-dimensional unsteady flow to elucidate the phenomenon because the shape of the hand is three-dimensional. This research finally aims to investigate the three-dimensional vortex structure generated by sculling motion and clarify the relationship between effective propulsion behavior and vortex generation. In the present study, we visualized the vortical flow generated by hand during sculling.