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why do golf balls have dimples physics

why do golf balls have dimples physics插图

Aerodynamics

Why do golf balls have those little dents in them?

Those dimples serve an aerodynamic purpose. The reason why golf balls have dimples is a natural selection story. Originally, the golf balls were smooth; but the golfers noticed that the older balls, which had been beaten with nicks, bumps, and slices in the cover, seemed to fly further.

Why are golf ball dimples make it go further?

Lift. Lift is obviously the motion which occurs when an object moves upwards,and dimples in your golf ball help to produce this by creating more pressure at the top …Pressure Drag. As a concept,drag is relatively straightforward. …Skin Friction. …More lift +less drag = more distance. …

Why do golf balls have depressions on it?

The dimples cause turbulence in the air around the ball, creating lift and reducing drag, so a dimpled golf ball travels farther and straighter than a golf ball with a smooth surface would. The dimples give the golfer more control over the flight of the ball.

Why does golf ball have more mass then a tennis ball?

A golf ball has more mass than a tennis ball because.Contains more matter. Which is a physical change. Evaporation. What is true for all chemical reactions. Total mass of reactants equals the total mass of the products.

Have Golf Balls Always Had Dimples?

However, at some point in the 1800s, players noticed that their dented golf balls actually performed better than the perfectly smooth ones.

Are All Golf Ball Dimples the Same?

After learning how vital dimples are to a golf ball’s success, you may be surprised to learn that golf ball dimples are not regulated. They can have different shapes, different depths and appear in varying amounts on balls.

Why are dimples important in golf?

Aerodynamics is all about altering the lift and drag on an object, and this is the purpose of the dimples on a golf ball. Aerodynamics is extremely important in the game of golf.

How do dimples affect golf ball lift?

A golf ball’s lift comes from its spin. The spinning motion of a golf ball causes the pressure beneath the ball to be greater than the pressure above, which causes lift. The dimples optimize the spinning effect by cutting down drag and increasing the ball’s lift.

Why do golf balls have dimples?

A golf ball’s dimples allow for a smooth, controllable flight and also give the ball lift by impacting the way the air flows around the ball. There is science behind the design, and the dimples are not just for show.

How does a golf ball travel?

To get your ball to travel, you also need lift, and golf ball dimples are key in this aspect as well. About half of the lift you get on a golf ball is caused by the spin on the ball, but the other half is due to how well the dimples optimize this spinning.

How deep is a golf ball dimple?

The average depth of a golf ball dimple is 0.010 inches, but this too can vary slightly.

Did Golf Balls Always Have Dimples?

Like many other great inventions in history, dimples on a golf ball were discovered accidentally. Throughout history, golf balls took on many different designs. At one point, they were even constructed with feathers inside them.

What do the Dimples on a Golf Ball do to Ball Flight?

A great alternative to this question is, what would happen if there were no dimples on the golf ball? This experiment was conducted by Titleist several years back, and the result was a line drive type shot that wavered on its line. The ball only went about half as far as a dimpled ball, and the ball flight was not nearly as high.

Are There Different Dimple Patterns and How Do They Affect Ball Flight?

Most golf ball dimples are spherical. They follow a pattern, and generally, one will be shallow, followed by a deep dimple across the surface of the golf ball. Major manufacturers seem to be more likely to change materials or interior makeup of a golf ball before they alter the dimple pattern.

How Many Dimples Will Work Best for My Game?

If all this talk about golf ball dimples has you thinking that the number of dimples on your ball could be causing your slice, you are probably looking for a solution in the wrong place.

What is a dimple in golf?

Dimples give the golf ball the correct amount of lift and drag to promote the best possible result with each swing. Nick Lomas is the founder of GolfSpan, an avid golfer, not quite a pro but has over 15-years of experience playing and coaching golfers from all over the world.

Why do golf balls have dimples?

Very simply stated, if a golf ball were smooth, the air would flow quickly over the top and create quite a bit of turbulence behind the ball.

How many dimples are there on a golf ball?

The average golf ball has about 336 dimples on it. Most have anywhere from 250 to 500. The interesting thing about dimples is that they must be symmetrical, but there is no limit to how many you can have on a ball. There was once a golf ball created with 1700 dimples on it.

What is a dimple in golf?

The dimples on a golf ball are simply a formal, symmetrical way of creating the same turbulence in the boundary layer that nicks and cuts do. What is the history of golf?

What is the effect of nicks and cuts on the ball?

At some point, an aerodynamicist must have looked at this problem and realized that the nicks and cuts were acting as " turbulators " — they induce turbulence in the layer of air next to the ball (the "boundary layer"). In some situations, a turbulent boundary layer reduces drag, making the golf ball go further.

What are the two types of flow around an object?

If you want to get deeper into the aerodynamics, 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.

What causes early separation of the laminar boundary layer?

If the contour of a body contracts at a local Reynolds number below that where natural transition to a turbulent boundary layer occurs , the still laminar boundary layer will cause early separation. The dimples of a golf ball help to trip the boundary layer early into its turbulent version, thus delaying separation and reducing drag.

What happens when a laminar boundary layer is shear?

Since the energy transfer across the stratified flow in the laminar boundary layer is reduced to shear, the molecules close to the wall will lose speed quickly, so that even at a modest pressure rise downstream separation occurs quickly.

What happens if you scuff a baseball ball?

In baseball the answer is simple. If you get caught intentionally scuffing the ball, you get in trouble and the ball gets replaced. The game is balanced around an un-scuffed ball. In cricket, scuffing the ball is actually part of the game mechanics. You’ll see players intentionally scuffing one side of the ball to create an uneven effect that permits the bowler to have more control over the ball.

What is the meaning of "back up"?

Making statements based on opinion; back them up with references or personal experience.

Can you put dimples on anything?

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).

Do dimples reduce drag?

To my knowledge there isn’t anything that uses dimples to reduce drag. It’s weird to hear why dimples are useful and help the ball go farther while at the same time finding no other examples.

Do you need dimples for shot putts?

In shot putt, I think they giggle at the idea of air friction against a 16 pound projectile, so dimple s aren’t needed.

Why does the laminar boundary layer have a smaller wake?

The transition from the laminar to turbulent boundary layer occurs for lower Reynolds numbers, due to small vortices induced by the dimples. This generates a smaller wake and therefore a smaller drag.

Why does the Reynolds number decrease when the ball reaches its maximum height?

The explanation comes from the fact that the drag force, acting against the motion of the ball, is much smaller for the golf ball (for a reason addressed at the beginning) throughout the flight. When the ball reaches its maximum height, the potential energy, which is proportional to the height, is also at its maximum. This energy transfer is done in detriment of kinetic energy; the ball goes slower. Hence, the Reynolds number decreases (or equivalently, the spin factor increases) and the drag increases as a consequence.

Why are dimples important in golf?

Dimples are famously crucial for the aerodynamic properties of a golf ball: They generate a turbulent flow that reduces the ball’s drag. However, doesn’t this sound counterintuitive? In general, smooth objects are more aerodynamic than rough ones. In today’s blog post, we will dig into the details of this apparent paradox; learn how to use this knowledge to model the trajectory of a golf ball with the COMSOL Multiphysics® software; and, finally, find the best angle to hit the ball. Keep reading for a hole in one…

What is the Reynolds number of a golf ball?

Comparison of the turbulent wake behind a golf ball and a smooth sphere. The Reynolds number is around 1e5.

How are vortex streets generated?

Throughout history, the flows around many different shapes have been studied by scientists. For example, vortex streets are generated by the flow around cylinders. Although a sphere does not generate this type of large alternating flow structure, the flow characteristics can also be linked to the Reynolds number. For a sphere of diameter in a fluid of density , dynamic viscosity , and velocity , it is defined as:

How to implement Eq 8?

The easiest way to implement this problem is by using the Events interface in a 0D component that can both solve the system of Eq. 8 using a Global Equations node and also stop the computations when the ball touches the ground ( ).

What are the quantities xt and yt?

The quantities xt and yt are the time derivatives of the position, computed by the Events interface.