242 野球ボールの軌道解析に基づく空気力モデルに関する実験的研究(飛翔体の空力特性)

抄録

We conducted the experimental and numerical trajectory analysis of the baseball and investigated the aerodynamic characteristics acting to the baseball. The optical images of the ball released from the pitching machine are taken by the high-speed camera and the translational and rotational motions of the ball are computed by the image processing. In the numerical analysis, the flowfield around the ball is assumed as the ideal fluid and the motion of the sphere without the seam are computed. We compared the aerodynamic characteristics of the baseball with those of the ball used in the lacrosse to investigate the effects of the seam to the motion of the baseball. The experimental results showed that those effects induced the gaps of the forces acting to the ball and of the trajectories between them. Although the aerodynamic coefficients are measured under the steady flow condition in general, they are modified as the parameters for the unsteady flow from the differences between the experimental and the numerical results.