Why do golf balls have dimples?

09.03.2015

Have you ever wondered why do golf balls have dimples? It sounds at least strange that something we want to throw as far as we can, is not as smooth as possible. Actually, a classic golf ball with dimples travels more than twice as far as a smooth ball with the same weight and size.

 

The reason behind this comes from the aerodynamic characteristics of laminar and turbulence airflow. Whenever an object moves through the air, the very first layer of air close to the object's surface is slowed down by the friction, causing a boundary layer moving more slowly.

 

 

At the front of a non-dimpled ball the boundary layer is smooth and the air around it flows with very low drag. Farther back instead, the airflow separates from the ball, creating a large amount of drag. Laminar flow is relatively easy to separate, so considering a smooth ball moving through the air, it brakes right behind it. If the ball has dimples, the laminar flow is broken up very close to front part of the ball and the turbulence caused, highly energized, resists to airflow separation. This effect causes the drag wake to be smaller in diameter, thus allowing a greater traveling distance.

 

The amount of drag caused by the disruption of the laminar airflow is relatively small compared with the drag of the larger wake.

 

Source: Flight Instructor Andrea Vignati, Flying Academy

Foto: Wiki

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