Dynamics analysis of human swimming movement using PIV and development of swimming simulation model

粒子图像测速技术（PIV）使我们能够可视化和分析非定常流场。这种方法通常用于小范围的测量，如分析气流，游泳/飞行生物的机制。本研究的目的是通过利用PIV方法分析游泳人体周围流场的非定常特征，建立游泳人体仿真模型，阐明人体在游泳过程中的推进机制，这是首次在世界范围内利用PIV分析更大的测量区域，如游泳人体周围的流场。PIV研究结果表明，游泳的人利用涡流（动量）进行有效的推进。手和脚的复杂运动是由产生推力的机体区域周围的涡流和环流来处理的。明确了射流是在手周围的脱落涡和束缚涡之间产生的。这种动量的变化解释了手产生推进力的原因。游泳人体仿真模型的研究结果表明，在计算机仿真中再现了水下海豚踢腿的动力学过程。通过确定三个流体系数（附加质量Fa，法向阻力Frr，切向阻力Ft）。在此基础上，计算了水下海豚式踢腿运动产生的推进力和关节力矩。阐明了水下海豚踢腿的推进力主要是由足部产生的。此外，还验证了踝关节柔韧性与游泳成绩之间的关系。

Particle Image Velocimetry (PIV) enables us to visualise and analyse the unsteady flow fields. This method has usually been used for small measurement area like an analysing the airflow, mechanism of swimming/flying creatures.The purpose of this study was to clarify the mechanism of human propulsive mechanism during swimming by analysing the unsteady characteristics of flow field around swimming human using PIV method and by developing the swimming human simulation model, This is the first attempt using PIV to analyse a larger measurement area such as the flow field around a swimming human all over the world.The result of PIV study suggested that the swimming human applies the vortices (momentum) for effective propulsion. The complicated movement of hands and feet are dealt with the shed vortices and the circulation around the thrust generating body region. It was clarified that the jet flow is generated between the shed vortex and bound vortex around the hand. This change in momentum explains the propulsive force generated by the hand.Result of the study of swimming human simulation model showed that the dynamics of the underwater dolphin kick were recreated on the computer simulation. Through identification of three fluid coefficients (added mass, Fa; resistive force for normal direction, Frr, resistive force for tangential direction, Ft). Furthermore, the generated propulsive force and joint torque was calculated during underwater dolphin kicking motion. It was clarified that the propulsive force during underwater dolphin kicking was mainly generated by feet. In addition, the relationship between the flexibility of ankle and swimming performance was verified.