Find out how the dimples on the surface of a golf ball change the flow of air and affect the distance.
If you’ve ever looked closely at a golf ball, you may remember seeing the dimples, the bumpy grooves covering the surface. This unique surface is something that anyone would be curious about at least once. Why are there dimples? Is it because golf balls are made bumpy so that they can fly farther? Common sense tells us that a smooth surface would be better for sending a ball far. This is because a smooth surface seems to reduce air resistance. In fact, for many flying objects, especially aircraft, the goal is to maintain a streamlined, sleek exterior as much as possible to minimize air resistance. So why is the golf ball the only exception to this rule and has a bumpy surface? To find the answer to this question, we first need to look at the history of the golf ball when it was first created.
When golf balls were first created, all of them had a smooth surface. At the time, golf was mainly a sport for the aristocracy and the upper class, and the balls made with the technology of the time were mostly made by hand using leather. These early golf balls were not only simple to make thanks to their smooth surface, but they were also beautiful to look at. However, as time went on, golfers discovered an interesting fact. The idea was that a ball with a rough surface that had been used for a long time would fly farther than a new, smooth ball. How could a ball with a rough surface fly farther? This discovery left many golfers wondering, and it was subsequently studied by scientists.
To answer this question, you need to understand a little bit of fluid dynamics. There are four forces that act on an object as it flies through the air. First, thrust, which is the force that moves the object forward. Second, lift, which helps the object stay up. Third, drag, which hinders the object’s movement. And finally, there is gravity, which pulls objects to the ground. The force associated with the dimple of a golf ball is drag. There are two types of drag. The first is friction drag, which occurs due to friction between the fluid and the surface of the object, and the second is pressure drag, which occurs due to the pressure difference that occurs when an object moves back and forth. In general, friction increases when the fluid is highly viscous, the surface of the object is rough, or the surface area of the object is large. On the other hand, the pressure drag depends on how streamlined the object is, and the more streamlined the object is, the less the pressure drag.
Golf balls are not as streamlined as aircraft, and because they are small, they have a small contact area with the air. Therefore, golf balls are more affected by pressure drag than friction drag. Let’s take a closer look at how pressure drag works. When an object that is not streamlined flies through the air, the air around the ball initially flows along the surface of the object, but then detaches from the surface at the back of the ball. This is called “flow separation.” This is a phenomenon in which the airflow does not follow the surface of the object all the way, causing the back to become like a vacuum. This causes the front of the ball to have high air pressure and the back to have low air pressure, creating a strong pressure difference from front to back. This pressure difference pushes the ball backward, creating the force of drag.
The dimples on the surface of the golf ball play an important role in this. Dimples are not just decorative elements, but they also physically add momentum to fluids. When air passes over a bumpy surface with dimples, the air flow becomes irregular depending on the shape of the dimples. This adds momentum and causes the air flow to follow the surface of the ball for a longer period of time. In other words, dimples delay the separation of the fluid. If the separation of the fluid occurs late, the vacuum formed at the back of the ball is reduced, and the resulting pressure drag is reduced.
Another important effect caused by dimples is rotation. Golf balls usually rotate when hit, and this rotation also affects the ball’s distance and direction. In particular, dimples make balls with backspin fly more stably and further. Smooth balls without dimples do not induce such airflow and thus have a relatively shorter flight distance. In fact, when comparing the flight distance of smooth golf balls and dimpled golf balls, there is almost a twofold difference.
In conclusion, the dimple of a golf ball plays an important role in effectively reducing air resistance and improving the ball’s distance. Thanks to the dimple, the ball can fly farther and more stably. This scientific design of the golf ball is the result of a long period of experience and research, and it is an important factor that helps golfers maximize their skills.
