A FLOW VISUALEATION OF UNDULATORY UNDERWATER SWIMMING -A PILOT STUDY OF THREE DEIMENTIONAL AMALYSIS

Hirofumi Shimojo, Ryo Murakawa, Yasuo Sengoku, Jun Sakakibara, Shozo Tsubakimoto, Hideki Takagi

Abstract


The purpose of this study was to visualize the flow characteristic behind a swimmer during undulatory underwater swimming (UUS). A male college swimmer performed dolphin kicks in a water flume channel (flow velocity was set at 0.8 m+sl). By using the stereo PIV system, we captured the flow vector field in cross-sectional areas behind the swimmer and the swimmer's motions with a synchronized motion capture system. The vector fields were averaged for each kicking phase, and for spatial cross-sectional plane. This enabled visualization oft he three dimensional flow field in UUS. The results showed that the swimmer created a counter vortex pair around the feet before the downward kid, and this appeared to assist the generation of thrust during the down kick motion.

Keywords


PIV; vortex; dolphin kick; motion capture

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ISSN 1999-4168