Abstract
The effects of dimples on a golf ball surface are known as the results of boundary layer control; (1) drag reduction, (2) lift production in back-spinning, and (3) trajectory stabilization. The present paper describes the effect of (2) lift production mentioned above. We analyzed its aerodynamics theoretically, measured both coefficients of drag and lift simultaneously for model dimpled spheres using the wind tunnel, visualized the flow field around each model sphere by the smoke wire method, and investigated the characteristics of lift production dependent on the back-spin speed. We verified that a smooth sphere produces the negative lift, in low back-spin speed, and that the dimples make the lift positive always. Hence asymmetric separations determine the descent angle of wake. We also found that the coefficient of lift measured is proportional to the descent angle of wake visualized, same as the result of our analysis.
