Flying characteristics and flow pattern of a sphere with dimples

It is known that the flying characteristics of the golf ball is influenced by flying speed, rotational frequencies and the dimples, etc. In this study, the drag and lift acting on the test balls are measured using a three components loadcell by changing Reynolds number and the spin rate ratio, the number and the depth of dimples. And the flow around the balls is visualized by applying the oil film method and PIV in the stationary state. From these results, the aerodynamic drag and lift coefficients of the balls in the stationary and the rotational state are made clear.