In this blog post, we’ll explore the principles behind how the dimples on a golf ball’s surface reduce air resistance and increase distance, as well as the historical evolution of these dimples.
What is the secret behind a golf ball?
“Inbee Park wins the gold medal!” South Korea’s Inbee Park won the gold medal in the golf event at the 2016 Rio Olympics. When watching a golf match, you’ll notice that players send a lightweight golf ball very far with a single shot. As a golf ball flies through the air, it encounters air resistance. Since the ball itself is quite light, one might expect its speed to drop rapidly when subjected to this resistance. According to data from TrackMan, a golf data measurement equipment company, in 2016, the average driving distance for male golfers was approximately 246 meters, while for female golfers it was approximately 199 meters. In professional golf today, players’ driving distances have increased even further, and TrackMan’s 2024 tour average data shows that players are now hitting the ball farther than ever before with higher ball speeds and lower spin. So how can a golf ball fly so far? The secret lies in the dimples on the surface of the golf ball.
How do dimples increase a golf ball’s distance?
One of the key factors that allows a golf ball to fly farther is the dimples on its surface. Dimples are small indentations carved into the surface of a golf ball in a specific pattern. So, how can a golf ball with dimples fly farther than a smooth, dimple-free one? First, let’s consider what happens when a smooth ball travels through the air at high speed. At the front of the ball, high pressure builds up as the air collides with it, while at the rear, the airflow separates from the surface early, creating a wide area of low pressure known as the wake. This creates a significant pressure difference between the front and rear of the ball, causing it to experience substantial drag—air resistance—opposed to its direction of travel. Consequently, a smooth ball experiences significant resistance as it flies, causing its speed to decrease rapidly. Now, let’s examine a ball with dimples. As the ball moves through the air, the dimples cause the boundary layer of air flowing along the ball’s surface to become turbulent, causing the air to flow along the surface for a longer period. As a result, the point at which the airflow separates from the ball’s surface moves farther back, and the size of the wake formed behind the ball decreases. When the wake becomes smaller, the pressure difference between the front and back of the ball decreases, reducing drag. Ultimately, a dimpled ball experiences much less air resistance than a smooth ball, and because its speed decreases less under the same conditions, it can travel a greater distance. Without dimples, a golf ball would struggle to achieve the long-distance flight it currently does, and even when struck with the same force, its distance would be significantly reduced.
What is the vortex phenomenon caused by dimples?
So, what is the vortex phenomenon caused by dimples? A vortex refers to the phenomenon where air rotates or swirls within a fluid flow. When a golf ball moves rapidly through the air, the airflow follows the ball’s surface and then breaks away from the rear, forming a complex, swirling wake behind the ball. These vortices and turbulent phenomena can also be observed when an airplane flies through the sky. Sometimes, swirling clouds appear in the wake of an airplane; this phenomenon is also related to the vortices generated by the airflow around the aircraft. In this way, various forms of vortices can occur around objects moving rapidly through the air. This phenomenon also occurs with golf balls, where the dimples alter the airflow. However, it would be inaccurate to simply explain the role of dimples as “vortices formed behind the ball pushing it forward from behind.” Instead, the dimples create a turbulent boundary layer on the surface of the golf ball, delaying the separation of the airflow from the surface and, as a result, reducing the low-pressure wake and drag behind the ball. Furthermore, the aerodynamic properties of the dimples influence the lift generated as the golf ball spins.
How did the dimples on golf balls come about?
So how did people discover that dimples allow a golf ball to fly farther? When golf first began in England, the balls used did not have dimples like those found on today’s golf balls. Through repeated use, golfers empirically discovered that balls with scratches or damage on their surfaces flew farther than new, smooth ones. Based on these observations, they began intentionally creating various patterns of indentations and grooves on the surface of golf balls, and research was conducted to determine which surface patterns would make the ball travel farther. Later, William Taylor of the United Kingdom researched methods for creating a regular pattern of concave grooves on the surface of golf balls, and in 1905, he registered a patent for a dimple design, marking a significant development that led to the dimpled golf balls we use today. Research into the aerodynamics of golf balls continued thereafter, and aerodynamicists P. W. Bearman and J. K. Harvey conducted experimental studies on the relationship between the shape of a golf ball’s dimples and aerodynamic forces. Through wind tunnel experiments, they analyzed the differences in lift and drag depending on the shape of the dimples, and this research played a crucial role in understanding and improving the flight characteristics of golf balls.
How can dimples be utilized in science?
As shown, golf balls can fly farther by altering airflow and reducing drag thanks to their unique surface structure—the dimples. The turbulence and changes in airflow created by dimples may initially appear to complicate the flow of air, but they ultimately benefit the golf ball’s flight. While aerodynamic phenomena such as vortices and turbulence can be put to good use—as demonstrated with golf balls—they have long been regarded as sources of unwanted errors and uncertainties in scientific experiments and engineering design processes. Nevertheless, through extensive research and experimentation, we are coming to understand the principles behind these phenomena and, in some cases, discovering ways to utilize them to our advantage. Therefore, rather than simply trying to eliminate elements in our surroundings that appear harmful or inconvenient, we need to adopt an attitude of constant reflection and effort—understanding their underlying principles and viewing them from a new perspective—so that we can develop them in a beneficial direction.
