If you think it’s windy outside, that’s nothing compared to the wind speeds inside the wind tunnel at Virginia Tech. Built by NASA during World War Two to test aircraft stability, it remains one of the best of its kind in the world.
“It’s called the Stability tunnel and there’s a reason for that it was designed to measure stability so it really wasn’t designed to do the kinds of things that we’re doing now,” says William Devenport, who has been the Director of the Stability Wind Tunnel at Virginia Tech for 10 years. He wasn’t here when it came to the university, but he knows the history.
“Then about 1958, for reasons that I think were later regretted, NASA decided that it didn’t want the wind tunnel any more. And it sold it to Virginia Tech for; I think it was a 99% discount off the scrap value, so I think it was $1700. And it took 67 truckloads to transport it from NASA Langley to Blacksburg.”
Back then this part of campus was a cow pasture. Now it’s part of a bustling crossroads of old and new. From the outside, the wind tunnel looks like some kind of pop art rendition of a huge air duct – more cartoonish than high tech
“A lot of what makes it high tech is what goes on inside.”
Inside are several high-speed fans as large as 15 feet in diameter. They push air through a series of smaller and smaller chambers, creating winds inside that can reach one hundred ninety miles an hour.
We go through two heavy-duty doors into a chamber that is so insulated you can ‘feel’ the quiet. About ten years ago, they started using the stability wind tunnel to measure sound as well.
“Our wind tunnel configuration, particularly the acoustic configuration is something that is invented at Virginia Tech, so we’re kind of leading the field in learning how to exploit this kind of configuration.”
And that’s caught the ear of large Wind energy companies who come here from around the world to rent testing time in the tunnel. “Because we’re the only wind tunnel in the world that can air acoustically test wind turbine blade sections near full scale conditions.”
“What we’re trying to do is, we’re measuring different geometries and we’re trying to figure out, in absolute terms, which is the quietest,” says Aurelien Borgoltz,Research Scientist & Assistant Director of the VT Stability Wind Tunnel.
“The main goal of the research is to make them more efficient and quiet, so they can be extended closer to population areas.”
For this experiment 117 small microphones are mounted on a panel inside an echo proof chamber. The sound of the tunnel’s huge fans is kept out, isolating the sound of device being measured. You can hear this noise increase as it spins faster.
Devenport says the main role of this wind tunnel is for undergraduate education, but as interest in wind power grows, more and more companies are looking to book time in it.
“The percentages vary but we run about 30% of the tunnel time is run purely for undergraduate education. I see these experiments and these undergraduate tests as the main purpose of the tunnel regardless of what our national or international profile might be. The whole point of this thing is to try to give undergraduate students a state of the art experience.”
A few years back, Japanese scientists came to Virginia Tech to use the wind tunnel. They were so impressed, they copied it and now there is a sister tunnel like it operating there with another on the way in Denmark.
