抄録
Golf balls are pitted on their surface with hundreds of small hollows called dimples in order to lengthen the range. The effects of dimples are known as the results of boundary layer control; (1) drag reduction, (2) lift rise in spinning, and (3) trajectory stabilization. The present paper describes the effect of (1) drag reduction mentioned above. We measured the drag coefficient of model dimpled spheres, visualized the flow field around each dimpled sphere by means of the smoke wire method, and made clear the characteristics of drag reduction dependent on the dimensions of dimples and their optimizing design conditions. Furthermore we also propose the concrete procedure to design optimally the dimpled spheres with the effect of drag reduction for general purpose.
