As a 6 handicapper, I've long studied golf balls - simply because the one you don't use, is always the best flyer - at least it is until you tee it up, then it magically morphs into a slicing banana. 8)
Golf + Rocketry = hand in hand
The dimples reduce the drag on a golf ball by redirecting more air pressure behind the golf ball rather than in front of it.
In addition, the dimples change the levels of pressure by bringing the main air stream very close to the surface of the golf ball. The dimples increase the turbulence in the layer of air located next to the surface of the ball. This high-speed air stream near the ball increases the amount of pressure behind the ball-thereby forcing the ball to travel farther.
There are two types of flow around an object: laminar and turbulent. Laminar flow has less drag, but it is also prone to a phenomenon called "separation." Once separation of a laminar boundary layer occurs, drag rises dramatically because of eddies that form in the gap.
Like I said, Golf and Rocketry go hand in hand - though I tend to find more rockets than golfballs.
Turbulent flow has more drag initially, but it also has better adhesion, and therefore is less prone to separation.
Therefore, if the shape of an object is such that separation occurs easily, it is better to turbulate the boundary layer (at the slight cost of increased drag) in order to increase adhesion and reduce eddies (which means a significant reduction in drag). Dimples on golf balls turbulate the boundary layer.
Check this link for more info:
https://www.adsources.com/GOLF/GOLFINFO/golfpa2.htm
Hope that helps,
