What are the dimples for on a golf ball?

Question

do they have a purpose? I was just looking at a golf ball and got curious.. i dunno just interested...

Answer 1

the ball would drop almost instantly if it didnt have dimples

Answer 2

aerodynamics

Answer 3

I think they're to increase traction between the ball and golf club so you have more control over it's direction & trajectory when it's hit

Answer 4

they decrease wind resistance on a ball. They also force the ball to spin when hit so it goes in a straight line rather than having it curve.

Answer 5

I think it is so the ball could stand on the tee by itself without rolling off of it.

Answer 6

When a golf ball is flying through the air, it has three forces on it. Two of them are gravity and drag from the air. In addition, if the golf ball is spinning, there will be a Magnus force on it (which may point up or down or either side, depending on how it is spinning -- the Magnus force cannot point along the flight path of the ball however -- see our answer on the Magnus force for more information).

The main goal of making a golf ball go farther however is to reduce the force of drag as it flies throught the air. In general, turbulence increases drag, because the energy needed to stir the air up and make it swirl around is energy that the ball has lost. One might think that a rough ball will induce more turbulence in the air than a smooth one, but it depends on how fast the ball is going. For balls going slowly through a viscous fluid, then the fluid just moves a bit to the side as the ball passes, and then it returns more or less to where it was. If the fluid motion is smooth, we call the motion "laminar", otherwise it is "turbulent." A ball moving quickly through a fluid like the air will have air flowing in a laminar fashion in some places and in a turbulent fashion in others. Directly behind the ball there will be a turbulent "wake", and surrounding that will be smoothly flowing air. The whole idea behind reducing the drag is to make the turbulent wake small.

The air that slides past the ball very close to it is called the "boundary layer". At the place where the turbulent wake starts is called "separation of the boundary layer" where the smoothly flowing air departs from the ball and does not close up behind the ball nicely but rather swirls around in small vortices. If the boundary layer can be encouraged to stick to the ball a little longer, then the turbulent part of the wake can be reduced. It turns out that adding a little extra turbulence in the boundary layer itself all over the ball allows the main smoothly-flowing air currents to stay closer to the ball and delays the separation of the boundary layer. Some nice pictures of balls in wind tunnel showing this effect can be found here.

There is also an increase in the Magnus force, giving the ball some lift when it is spinning in the correct direction. This force helps keep the ball in the air longer, allowing it to travel farther.

People have thought of putting dimples on everything from swimsuits to cars to airplanes. You only get an advantage from these dimples if the boundary layer can be made to stick longer to the object. Some cars just have vertical flat ends to them where the trunk comes down and there is no way to reduce the turbulent wake of these no matter how dimpled the paint is. And the boundary layer stays with airplane wings except maybe a bit at the ends (some gain can be made by putting small rods out on the tips or on the trailing edges of the wings).

Answer 7

The dimples are similar to the shape of the underside of an airplane wing (concave). So the dimples help the ball to stay up longer. Otherwise the ball would not go nearly as far as it does. Amazing what a little dimple can do. Or in this case, many little dimples.

Answer 8

Mr. Peanut went pretty in depth.  Dimples are made simply to reduce the amount of drag on the ball.

Here's a little history on golf balls:  A featherie was the first golf ball.   A featherie is a hand sewn leather pouch stuffed with goose feathers and coated with paint. The feathers in the ball were enough to fill a top hat. They were boiled and put in the cowhide bag. As it cooled, the feathers would expand and the hide would shrink, making a compact ball. Due to its superior flight characteristics, the featherie remained the standard ball for more than two centuries.

In 1848, the Rev. Dr. Robert Adams (or Robert Adam Paterson)[1] invented the gutta-percha ball (or guttie). The gutta was created from dried sap of a Sapodilla Tree. The sap had a rubber-like feel and could be made round by heating and shaping it while hot. The ball suffered from cuts and nicks from the golf club constantly striking the ball, many noticed the ball flew better with these little defects.  Thus, makers started creating intentional defects in the surface to have a more consistent ball flight. Because gutties were cheaper to produce and could be manufactured with textured surfaces to improve their aerodynamic qualities, they replaced feather balls completely within a few years.

This ultimately led to today's golf balls, with different manufacturers creating balls from different materials, experimenting with layer numbers, dimple size, and even dimple shape.