Golf balls are the fastest balls in the sport

Golf balls are the fastest balls in the sport, reaching speeds of over 300 kilometres per hour. What must a ball be like that flies as far as possible at such an initial speed and lands near the hole with the very first stroke? The size and weight are specified very precisely by the associations, the only freedom the manufacturers have in the design is the surface. And the dents actually cause a drastic change in flight characteristics - the ball flies up to four times as far as a smooth ball.

This seems paradoxical at first glance. In the design of streamlined car bodies, the aim is to create surfaces that are as smooth as possible and along which the air glides in laminar fashion, i.e. without turbulence. This would also be ideal for the golf ball - if it had a streamlined shape.

But a ball is not an ideal body in a wind tunnel. At first, the airstream nestles up against its surface, but already at the apex, the air stream begins to break off. This creates a wide swirling zone in which there is a negative pressure. That slows down. A ball with dents creates small eddies on the entire surface, which ensure that the flow "sticks" better to the ball. The air flows laminar around the ball for longer, the swirl zone behind it is narrower. The result: The air resistance is halved.

But that's not all: A well-hit golf ball has a good portion of spin, a backspin. Due to the so-called Magnus effect (which is also involved in the spectacular "banana flanks" in football), this leads to a buoyancy force that makes the ball rise higher. And this lift is greater on a rough surface than on a smooth one. The ball rises higher on a flat trajectory than it would if it were smooth, and ends up falling relatively steeply to the ground - just the way golfers like it.