Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: chris on 16/02/2016 20:50:38

Title: What do the dimples do on the surface of a golf ball?
Post by: chris on 16/02/2016 20:50:38

Why do golf balls have dimpled surfaces? How does this affect the flight of the ball?

Title: Re: What do the dimples do on the surface of a golf ball?
Post by: CPT ArkAngel on 16/02/2016 21:25:40

Just a guess: they cause turbulence that will tend to stop the rotation of the ball... ?

Title: Re: What do the dimples do on the surface of a golf ball?
Post by: Colin2B on 16/02/2016 22:01:01

There are two types of flow around an object, laminar and turbulent.
Laminar flow - smooth layers - has less drag, but the layers can separate and then drag rises very quickly. This drag will typically form on the trailing edge of a ball or wing and eddies form in the gap caused by the separation. The dimples cause turbulence and although turbulent flow has more drag initially it also sticks to the surface better and so is less prone to separation.

Title: Re: What do the dimples do on the surface of a golf ball?
Post by: evan_au on 17/02/2016 09:42:47

Continuing the line of Colin2B...
The golf ball is hit with a backspin, and the golf ball meets the air with a very different velocity on the top and bottom surfaces.
Like an airplane wing, this gives the golf ball lift.
So a golf ball with dimples can fly farther than a perfectly smooth golf ball.
But the dimples also cause increased drag, so the ball tends to drop more vertically towards the end of its flight (compared to a perfectly smooth ball).
See: http://en.wikipedia.org/wiki/Golf_ball#Aerodynamics