The aim of this study was to visualize and to analyze the unsteady flow field around swimmer's hand during sculling motion using two-component Particle Image Velocimetry (2C-PFV). Also 3D-DLT motion analysis was executed to check the relationship between flow and the attack angle of the swimmer's hand. PIV allows us to visualize the unsteady flow field instantaneously and to estimate the fluid force. Two subjects were participated in this study. One was the ex-competitive swimmer (Sub.M), and the other (Sub.O) has no competitive carrier. Subjects were asked to keep their position by sculling motion in a swimming flume tank with 0.5 m/s flow speed. We focused on the transition phase from out-scull to in-scull. The attack angle of Sub.M reached nearly 90 degrees at just before the transition phase ; meanwhile that of Sub.O was nearly 70 degrees. As the result of flow visualization, Sub.M seemed to shed the vortex after the transition phase and to create the jet flow for thrust between his hand and shed vortex. On the other hand, Sub.O seemed not at the same situation. The results of present study suggested that ex-competitive swimmer created the propulsive force by generating the shed vortex using proper attack angle change, but the beginner could not obtain the propulsive force effectively.
