This post was originally published on Wired - Science

When it comes to engineering water features, “controlling turbulence is the name of the game,” says Garrett Young, who leads WET’s team of 40 engineers. In short, turbulence breeds chaos. It causes water to slosh, spill, and spray in ways that are difficult to predict. These effects are compounded by variables like air flow, temperature, or textured surfaces, which make it staggeringly difficult to get a large water feature to behave. To understand how water will move in such a complex system requires modeling water very precisely at the level of its individual particles—and that requires a lot of computing power. The environments in some of WET’s upcoming water features are so chaotic that the company is renting time on a supercomputer at Oak Ridge National Laboratory just to make their simulations.

“What we do is very simulation intense,” says Young. “But it allows us to give the illusion that we’re breaking physics.”

You know those plaza fountains that shoot up thin streams of water that then disappear underground through cracks in the tiles? They’re now a mainstay of corporate plazas everywhere, but that was originally WET’s idea. When they first floated the design for a client in Texas back in the 1980s, Fuller says no one outside the company thought it would work. The cracks in the tiles seemed too narrow to let the water drain fast enough. But if you work through the math, it’s the total lengths of the cracks around the tiles that matter, not their width—so there was more than enough space to move water off the plaza and into the underground collection pool.

fountain with image of guitarist

Courtesy of WET

“I made a couple of bucks betting all the stonemasons that the water would get out there,” says Fuller. “It just seems like magic because all the water disappears before your eyes.”

But even with all the theory in the world, things don’t always work as planned. The Bellagio fountain in Las Vegas was WET’s first major project and arguably its biggest claim to fame. Steve Wynn, the hotel magnate building the Bellagio, wanted the largest fountain in the world, complete with thousands of dancing water jets, some of which would send water over 300 feet into the air. But to blast water that high, traditional pumps just aren’t going to cut it. They would require an obscene amount of energy that would have to be dumped into the system all at once.

So instead, Fuller and his team developed what they refer to as “shooters,” giant water cannons that use highly pressurized air to blast water through a nozzle. These reduced the fountain’s energy needs to just a fraction of what they would have been had they gone with pumps. But when they installed the shooters in the Bellagio pool, there was a problem. The valves in the water cannons would get stuck open at random, sending a torrent of water streaming into the air. “It looked like Old Faithful,” says Fuller.

Wynn, who was spending $40 million on the project, was less than pleased, Fuller recalls. But when the WET team sent divers out into the pool to look for a problem, everything seemed fine. At the time, WET was still a small company and didn’t have its own research labs to use to figure out what was happening. So Fuller turned to a friend of his who worked as a scientist at Caltech to do a root cause analysis. Soon he had an answer: When air expands, it sucks thermal energy out of a system, which is why cans of compressed air like hairspray or computer dusters get cold when you use them. When pressurized air was fed into the shooters at the Bellagio, it caused temperatures to drop to -50 degrees Fahrenheit. This made large balls of ice build up in the valves and hold them open. The solution was simple: WET added a component to the pipe that caused the ice to form in a different section of the shooter rather than in the valve. But without getting into the fundamental science, the problem would have been difficult, if not impossible, to solve.