2408 PIV計測法を用いたモノフィン後流の流れ場の可視化(S43-2 スポーツ流体工学(2),S43 スポーツ流体工学)  [in Japanese] 2408 Visualization of Flow Field behind a Monofin Using PIV  [in Japanese]

The shape of monofin and the properties of the material have not be optimized yet, because it is difficult to know the unsteady flow field and to relate it to the unsteady flow force. To develop the efficient monofin, we need to know the details of the flow field around monofin. For this purpose, we constructed a system for measuring flow field and flow force. The flow field was visualized using PIV (Particle Image Velocimetry). It is known that the vortex behavior plays an essential role in the generation of flow force. Therefore, our aim is to know the characteristics of flow fields. It was found that the flow field in the wake of monofin consists of two types of vortices ; one is wing-tip vortex and the other vortex shed at the top and bottom dead points. The latter is called the inverse Karman vortex street. Simplified 3D picture of the wake was obtained.