by Jake Morrison

Created on: July 04, 2010   Last Updated: July 08, 2010

Golf balls have dimples because they maximize the distance the ball travels and allow more precise accuracy for the golfer.  This strange fact surprises many who once thought that the little indents are just for aesthetics.  The seemingly strange phenomenon that allows dimpled balls to travel up to four times farther than smooth balls was actually discovered by accident and has since changed the game of golf.

The story of why golf balls have dimples begins in the early 20th century when golf was becoming more and more popular.  Back then, experienced players played with smooth golf balls.  With time and repeated use, the surface of these once smooth balls would be replaced by a texture characterized by a series of bumps, nicks, and scrapes.  Some golfers, who were looking for a way to get a better shot, would test out different balls.  Golfers who tested old, used balls and found that these preformed much better than the new ones. 

Many experts began to look at the trend of golf balls seasoned with use going farther than new smooth balls.  It was decided that those cuts and scratches were acting as turbulators.  Basically, a turbulator is a factor that increases the rate of turbulence involved with and object.  In the event of a golf ball, this means that the nicked up surface was introducing turbulence into the layer of air around the ball as it sails toward the target.  The presence of the turbulence reduces the drag on the ball, which allows it to be more predictable and go a greater distance.  The dimples on a golf ball are simply formal, synthetic way of creating the same or better turbulence in the boundary layer that nicks and cuts do.

If you want to dive deeper into the aerodynamics of a golf ball, there are two types of flow around an object: laminar and turbulent.  Laminar flow, has less drag but is also prone to something called “separation”.  Once separation of the laminar boundary layer occurs, drag rises drastically because of gaps and backwards flow called eddies that form in those gaps. 

Turbulent flow has more drag initially but also better adhesion, and therefore is less prone to separation.  If the shape of an object is such that separation occurs easily, like the shape of a smooth sphere, it is better to tabulate the boundary layer.  That is done by the dimples which increase adhesion and reduce eddies.

Sports manufacturers were eager to supply for the growing demand of dimpled golf balls.  By the middle of the 20th century very few companies were still making smooth golf balls.  Dimpled balls have stayed the favored golf balls for almost all professional and amateur golfers
 
Typical golf balls have around three to four hundred dimples per ball.  Based on the average distance that is projected today, golf balls with dimples are capable of traveling up to four times the amount of distance that is achieved with smooth balls.  This difference is the reason that golfers choose the dimpled balls, which maximize distance, reduce drag, and improve predictability and accuracy

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