This article explains how dimples on the surface of a golf ball reduce air resistance to improve distance. We will analyze the scientific principles of how dimples increase lift and send the ball farther through flow control and Bernoulli’s theorem.

If you look closely at a golf ball, you’ll notice that instead of a smooth spherical surface, it has small indentations all over it. These are called dimples. Many people know that dimples help golf balls fly farther. However, you may not know exactly how dimples affect the ball’s flight or the science behind it. To understand this, it’s important to first understand the academic concept of flow control. Flow control is the study of how to regulate and control the flow of fluids, and its principles can be found in our daily lives through various engineering applications.

What is flow?

First, we need to explain the word flow. The states of matter can be categorized into solids, liquids, and gases, and fluids are liquids and gases. Flow is the phenomenon of these fluids flowing. Solids have a fixed shape and form, which limits their movement, while fluids flow freely and have no fixed shape. To make it easier to understand, think of students in a schoolyard. A solid is a fixed shape, like the students standing in a line, while a liquid is like the students moving freely around the playground. Gases are almost invisible and flow freely, like the students quickly exiting the playground after school.
With this understanding of the state of fluids, we can think about how to control the flow of fluids. While the movement of solids is easy to see, the flow of liquids and gases is not. Gases, in particular, are invisible to the eye, making it difficult to observe their flow directly. Studying the motion, shape, and properties of these invisible fluids and thinking about how to use them in real life is the essence of flow control.

Flow control in golf balls and the role of dimples

When a golfer hits a golf ball with a driver and the ball takes off into the air, several physical forces begin to act on it. Gravity on the ground and air resistance in the direction opposite to the direction the ball is traveling will interfere with the ball. It’s important to note that the ball doesn’t just fly in a straight line, it has a spin on it. In particular, a golf ball hit with a driver has a spin called “backspin” that greatly affects the ball’s flight trajectory.
A golf ball with backspin interacts with the air depending on the direction of rotation. Due to the viscosity of air, the air flowing around the ball is forced in the same direction as the spin. The viscosity of air is very weak, but when the ball is spinning fast, the effect is strong enough to change the ball’s trajectory. Like a changeup in baseball or a banana kick in soccer, golf balls use this physical principle of rotation to fly farther.

Bernoulli”s theorem and golf ball flight

Backspin on a golf ball causes different airflow on the bottom and top of the ball. At the bottom, the air is pushed in the same direction as it’s traveling, while at the top, it’s pushed in the opposite direction. This difference results in slower speed and higher pressure on the bottom of the ball, and faster speed and lower pressure on the top. This pressure difference gives the golf ball a lift force and keeps it in the air longer. This is one of the important reasons why golf balls can fly farther.
Bernoulli’s theorem is the physical law that explains this phenomenon. It describes the relationship between the speed of flow, pressure, and potential energy of a fluid, and shows that the faster the flow, the lower the pressure, and the slower the flow, the higher the pressure. In other words, just like on the road, when cars suddenly slow down, the gap between them closes and the pressure increases, in a fluid, the pressure increases as the velocity decreases.

The engineering effect of dimples

Now let’s take a look at why dimples play an important role in sending golf balls farther. A dimpled golf ball is more likely to receive stronger backspin than a smooth golf ball without dimples, resulting in greater lift. Dimples help to maximize lift by reducing friction with the air and changing the airflow around the ball. Therefore, dimpled golf balls can stay in the air longer, which increases their distance.
The shape, size, and placement of the dimples can change the ball’s flight characteristics. Research to date suggests that the ideal dimple structure is not yet fully understood, but flow control research is ongoing to optimize it. This research is playing an important role in improving the aerodynamic performance of not only golf balls, but also aircraft, ships, and cars.

The future of flow control and its engineering applications

Flow control is not just limited to golf balls. Flow control technology is having a major impact on many industries, including helping airplanes fly more efficiently, ships save fuel, and cars reduce noise. In the aerospace industry in particular, flow control is helping to maximize aircraft performance and reduce fuel consumption. These advances in flow control will play an important role in helping us develop better technologies and enable more efficient use of resources.
In the future, flow control will lead to more scientific discoveries and engineering breakthroughs and will make our lives easier, especially in sports equipment such as golf balls, but also in many other applications throughout life. Understanding and controlling the flow of air and fluids is one of the most important academic challenges for human creativity and technological advancement.