How does fuzz on a tennis ball make it fly faster? It seems counterintuitive to me.
Yes, it is counterintuitive. The reason for the fuzz is that a swirling layer of air close to the ball makes a good buffer between the ball and the main airstream. As a result, the main airstream flows most of the way around the ball before it breaks away as a turbulent wake. Without the swirling layer of air on the ball’s surface, the main airstream encounters backward-flowing air near the ball’s surface and breaks away from the ball early, leaving a larger turbulent wake.