Tunnel Tour

Nancy Marie Brown
May 01, 1997

A literature professor stopped me on my way to tour the Garfield Thomas Water Tunnel last May.

"I've heard," he said, dropping his voice, "that it goes all the way under campus—from that building on Atherton Street all the way over to the nuclear reactor. How else could they test the nuclear subs?" He raised his eyebrows in mock innocence.

I laughed.

"Seriously, though," he said, "I bet there are a lot of myths about that place."

Another professor, a historian who ended up accompanying me on my tour (along with his 6-year-old son and a representative from Senator Rick Santorum's office), was more genuinely suspicious. For years he had been pressing Research/Penn State to run an exposé of the University's defense-related research. "What're they really doing in that water tunnel?" he mused.

It's true most of the work has been classified since the water tunnel opened in 1950. Yet it's also, paradoxically, been in plain sight. "The blue tubes you see from outside?" Our tour guide, research assistant Kevin Farrell, gestured toward the wall of windows. "That's all there is."

Even the thick brochure the Applied Research Lab published to mark the water tunnel's dedication as a Historic Mechanical Engineering Landmark addressed the question: ". . . visitors may wonder why the Garfield Thomas Water Tunnel building, the site of classified research, has such large window panes." Hide it in plain sight? No: "The original designers wanted removable windows so that they could easily repair or change tunnel sections." No mystery after all.

And what about those nuclear subs? Farrell tries not to sound condescending, but anyone can see a nuclear sub won't fit into those "blue tubes." "We have models," he said. "We have to make allowances."

It isn't a tunnel the way the Lincoln Tunnel is a tunnel. Instead, it's a loop, a rectangular tube made of pipes of gradated size. The 48-inch-diameter test section resides in the skinniest 14 feet of the 257-foot loop: There the model—of a torpedo or a sub's hull, most likely—sits while the water rushes by it at 60 feet per second. (At least once the water stream was cranked up to 80 feet per second, former director Blaine Parkin recalled at the ASME ceremony, "and I tell you it was really hopping around on its foundations when we did that. But we got our data.")

Until 1990, the Garfield Thomas Water Tunnel (named for a Penn State journalism grad killed in World War II) was the largest high speed water tunnel in the world. On May 6 it joined the cable cars of San Francisco, the Apollo Command Module, the Johnstown incline, and the Penn State Heart-Assist Pump to be the 189th gizmo honored by the American Society of Mechanical Engineers as "a progressive step in the evolution of mechanical engineering." For the first time it let engineers analyze the wake left by an underwater propellor and so design quieter and more efficient propulsion systems.

Its "measurement capabilities," according to the commemorative brochure, are so numerous they begin to blur: propulsion—steady thrust and torque, dependency on Reynolds number and advance ratios; acoustics—shaft and afterbody unsteady thrust, side forces, flush-mounted unsteady pressures . . .; cavitation—inception, desinence, form, model angle of attack, nuclei content . . .; flow field characteristics—linear and circumferential surveys with five-hole pressure probes . . .; flow visualization—oil paint, laser light sheet, bubbles, mini-tufts, particle image velocimetry . . . (Wait: Oil paint? Laser lights? Bubbles? Maybe that's why the 6-year-old came on our tour.)

In 1995, the ARL received $73 million, more than 20 percent of the University's entire $344 million research budget, for Navy-related research on "advanced undersea technology." Much of this work depends on the tunnel. In addition, says an ARL press release, "tunnel-based research has been applied to artificial heart valves, vacuum cleaner fans, car heating and cooling systems, advanced propulsors for commercial ships, pumps for the Space Shuttle, and other products. Graduate students still conduct theses there and undergraduates can participate in research there through the Computer Science and Engineering Honors Program, the Mathematics Honors Program, the Engineering Cooperative Program, or as part-time employees."

The tunnel was given "a complete overhaul" in 1992, according to ARL director Ray Hettche. "The facility is in as good shape as when it opened," he noted, and "in its 48th year is probably as productive as it's ever been."

The water tunnel building was filled last May with more people than it usually holds in a year, stepping over cables, climbing up the brightly painted metal steps, eyeing the technicians' desks—bolts, clamps, clock radio—peering into the open hatches or through the plexiglass windows into the 48-inch-wide core of the tunnel's test section. TV crews were ushered into the control room, where banks of monitors give a power-plant air. Tourists wound past the lab's other, smaller tunnels: the wind tunnel, the glycerine tunnel, the 12-inch tunnel ("It lends itself to graduate research," said our tour guide, Farrell. "It doesn't have the overhead costs."). They clumped in the halls, reading panels on "Propulsor Design," "Fluid Dynamics," "Cavitation," "Flow Acoustics."

Cavitation—the noise and wear-and-tear bubbles cause—is Farrell's research area. We paused by a photograph from his dissertation work: "It illustrates the power of these exploding bubbles," he explained. "They blow the metal right away, just like tiny bombs."

A diagram of the tunnel sported a funny little 1940s figure in a Fedora. The legend gave the tunnel's capacity: 106,000 gallons.

"How often are you testing?" asked Santorum's aide.

"Continuously," said Farrell. He was dressed for the occasion in a green double-breasted suit and floral tie. "Sometimes we're doing shifts."

"Where does the water come from?" the historian asked. His 6-year-old was pulling on his arm. (Ask about the laser lights and bubbles, Dad.)

"It uses the public water supply," Farrell said. "But we don't change the water very often."

"Does it use a lot of power?"

Farrell shook his head. "The way the tunnel works, the only energy we're losing is through friction. It's a momentum thing."

"Does it leak?" I asked.

"Well, not leak, exactly . . . ," he smiled, then launched into the story. "I was initiated. They told me the pressure was down, and it wasn't. I had a probe in there, a half-inch diameter probe, and when I pulled it out a geyser came with it. I had a bath."

Director of The Garfield Thomas Water Tunnel is Michael L. Billet, Ph.D., 400 Garfield Thomas Water Tunnel Building, University Park, PA 16802; 814-863-3001; mlb@psu.edu. Ray Hettche, Ph.D., is director of the Applied Research Laboratory in the Intercollege Research Programs and professor of engineering research in the College of Engineering, 224 Applied Sciences Building, 814-865-6353; lrh3@psu.edu.

Last Updated May 01, 1997