Golf Ball Aerodynamics

Principle

Backspin leads to creation of lift force. Flight path of a golf ball is the main objective in golf ball aerodynamics, hence effect of drag cannot be ignored. The Magnus effect is the reason for generation of lift force and an example of flow around golf ball induced with a spin in shown in Fig.1.

Figure 1: Left to right flow over a golf ball with a clockwise spin at Re = 1950 [1]

Role of dimples

In a golf ball with a spin, an upward lift force is generated as the separation becomes asymmetric and wake gets deflected in the downward direction. Also, the major drag is pressure drag and not skin drag. Hence, the critical Re can be reduced with the presence of dimples in a golf ball as per analysis done and shown in figure 2. In the supercritical region, very less increase in the drag value of a golf ball can be seen. Hence, dimples are very effective in a golf ball.

Figure 2. A graphical relation between C_D, coefficient of drag and

Re, Reynolds number of a golf ball [1]

Source: 

1. R.D. Mehta, “Sports Ball Aerodynamics,” In SPORT AERODYNAMICS, Pg. 229-298. Edited By H. NØRSTRUD, Springer 2008.