Aerodynamics of the Golf Ball

Abstract

The aerodynamics of golf balls is still not well understood, primarily because the aerodynamic performance of the golf ball depends crucially on the details of the airflow over the ball, and those details are controlled by many factors. As the ball flies through the air, it develops lift and drag forces that depend on its velocity, spin rate, the atmospheric conditions, and, most importantly, the shapes of the individual dimples, and their arrangement over the surface of the ball. It has been said that it is more difficult to predict the performance of a golf ball than it is to predict the performance of a full-scale aircraft (see, for example, Moin & Kim, 1997). Nevertheless, a great deal of experimental work has been done, and our basic understanding is reasonably complete. In this chapter, we describe the factors that govern the aerodynamic performance of a golf ball. We will discuss the complicated nature of the flow over a spinning golf ball, and why the dimples, and their arrangement on the surface, play such a crucial role. We will describe the design methods used by the golf ball companies in their search for better performance, and the testing procedures used by the regulating bodies, notably the USGA, in enforcing the Rules.