Taking flight on the course

by Joe Kullman

Predicting how the smallest details of a golf ball's design will make it act in flight is a painstakingly complex task. That is, if you want to be accurate in the extreme.

The necessary mathematical precision simply can't be achieved without the analytical prowess of some of the most advanced computational technology, says Kyle Squires, a mechanical and aerospace engineer.

For that, Squires goes to Dan Stanzione and Arizona State University's High Performance Computing Institute (HPCI).

You want extreme? HPCI can go there.

The research into the aerodynamics of golf-ball flight is giving Stanzione's supercomputers a chance to flex their silicon muscles.

"To get an accurate picture of air flow around a ball, you have to measure the pressure being exerted on it from many, many small points within its ‘flight envelope.' That envelope is the immediate area around the ball," Stanzione explains.

"When you_re trying to find out what happens to a ball during each 1/500th of a second during flight, given a specific dimple pattern on the ball_s surface, that takes a nifty kind of computing trick," he says.

With assistance from Clinton Smith, an ASU doctoral student in mechanical engineering, Squires and Stanzione built a meticulously honed program to gauge pressure exerted from as many as 17 million tiny points surrounding a ball in flight.

To perform such calculations requires a computer system with 70 billion bytes of RAM. That is more than 100 times the memory capacity available on a standard desktop computer. It takes thousands of separate calculations that can keep about 30 processors working for as long as a day and a half.

The engineers also want to know what's happening with such varied factors as velocity, spin rate, and turbulence under the effects of different atmospheric conditions. That also requires finely tuned computing techniques.

"You have to divide up the work among a bunch of computers," Stanzione says. "The hard part is that everything has to be synchronized. The challenge is interconnecting processors in ways in which they can communicate. The computers have to talk back and forth while they're each working on the small pieces of a big problem. Otherwise, you get calculations that don't make sense."

The next step is Smith's job. He takes advantage of the supercomputer's processing power to study the influence of factors such as spin rate of the ball on forces that control its flight.

The result includes a colorful visual show of sophisticated three-dimensional animation that depicts aerodynamics in action. It shows the minute details of air flow around a ball. Such details give engineers ideas for ball designs to improve flight efficiency.

Amid all the heavy-duty computing, mathematics, and engineering, it's where this research brings a little bit of art into play with science.

For more information about engineering golf ball design, see "A different ball game."