NASA Ames Research To Close Largest Windtunnels

Makarand writes "The world's largest and second largest wind tunnels operated by the NASA Ames Research center will be shutdown after 60 years and may remain shut unless major defense contracts from the Pentagon or the private sectors are available. The largest windtunnel will be fired up for the last time in June for four hours. It will test the parachutes that will land the Mars exploration rovers onto the Red Planet next year. Fewer defense contracts and the increasing use of computer simulations are being cited as reasons for the windtunnels to face closure."

Comments

Racing...

[JakiChan]

I don't know about aerospace, but I know that even with the fancy computer simulations a lot of motorsports teams use windtunnels to test their designs. All of the biggest Formula 1 teams have them. Not being able to test in a windtunnel was supposedly one of the reasons that Jaguar (a.k.a. Ford) sucked so bad last year, and yet they certainly have the necessary computer gear. For some reason there are improvements that can only be tested in a windtunnel.

It's simply not

[vogon jeltz]

economical to operate such a beast, considering costs that are in the hundreds of thousands dollars per hour. The thing this windtunnel has going for it is its "full scale" character. You can test objects with a crossection of up to 12.1x24.4m^2. The_major_drawback is the maximum test speed of only 51m/s. Today, the big shots are tunnels which can do transonic speeds (up to Mach 0.9, or app. 300m/s). They are not full scale (it'd have power requirements in the order of_thousands_of megawatts). Every and each plane developpded by Airbus and Boeing is being thoroughly tested in tunnels. They are still needed, and will be for a while. Numerical methods only go so far and are mostly used in the early aerodynamical design phase. Polishing is always done in the tunnels because in order to obtain the precision needed to simulate an entire aircraft in 3D you'd probably need the power of a few hundred NEC "earth simulators" (no, I'm not kidding, that's what I do at university). By the way, the only tunnel I know of which is capable of simulating transonic flight (Reynolds numbers of 50e6 and above) is the European Transonic Windtunnel (www.etw.de).

Re:I�m surprised.

[Realistic_Dragon]

Because of better understanding of flow equivalence it's much easier than it used to be to test models in small windtunnels.

Reynolds numbers are roughly matched (by changing temperature and flow speed) to test in smaller-than-life wind tunnel tests, and it's now possible to do this for a much larger range of real word conditions (by using colder tunnels and high/low pressure and high velocity flows) with much smaller (ie cheaper) wind tunnels. It's also done much more accuratly, up to and including equivalent tests for supersonic and hypersonic flows. You just can't test a hypersonic (M5+) flow in a large wind tunnel, it would need a huge mass flow rate.

Combine this with the availability of cheap supercomuter time and the fact that your 3D models can be used for aerodynamic testing, systems integration _and_ CAD/CAM (so you only need to build one virtual model and not four - saving a huge heap of cash) and you have a sharp decrease in the need for large wind tunnels.

Local people will be happy

[theinfobox]

During the early '90s, I was stationed at Onizuka AFB which is right next to the Moffet/Ames facility. Back then, the wind tunnel had so many customers they were trying to get permission to operate the wind tunnel earlier and later than usual. Why did they need permission for the local government? This thing was LOUD. Once I was in a classroom that was right next door to the tunnel. Right in the middle of the lecture, it sounded as if a giant air conditioner was turned on. When we went outside, we figured out that it was the wind tunnel - you had to shout to be heard. The local communities (which had houses about 1.5 miles away) always complained about the noise. They didn't want it operationg before 7:30AM or after 9PM. NASA supposedly begged to get exceptions to this rule because they had "customers lined up from all over the world."

It is interesting to see now they don't have enough customers.

Re:I'm surprised.

[hackstraw]

Yeah, but the article said that the things were "hardly used". To quoteth the parent post:

wind tunnel tests the actual thing

The largest one could house a 737, which is not that large of a plane, and it can only attain a speed of 140 mph. What good is that? This is a very small subset of the "actual thing". I mean if you already went to the expense of creating a fullsize preproduction aircraft, why not throw a robot pilot, a computer and some sensors and fly the thing for real? Or throw a 1/4 size plane into a windtunnel that can test up to 700 mph?

Subsonic air flight is pretty much old hat by now. "Real" windtunnels can do things at speeds up to mach 7 or so to test the interactions of heat/pressure/speed that approach chaotic interactions and are very difficult to model or conduct a real test, and these windtunnels are at the threshold of our current technologies. This is what I would like to see from NASA. I see this as a sign of progress, not a sign of budget cuts.

I think I used to walk by there

[K-Man]

The warning signs were always really interesting, something like "Do Not Enter - Artillery Fire". This was on my normal route to lunch.

That link is really good; I wasn't aware of an online history. There were always tales of incidents, like this one:

By mid-1975 thousands of blowdowns, during which air was heated above the melting point of steel, had taken their toll. A flange between the nozzle and heater failed, spewing high-pressure gas and incandescent pebbles over a wide area. The tunnel building was damaged severely and numerous fires kindled in the surrounding area, but no one was hurt. Six months later the 3.5-foot tunnel was back in operation.

There's also a section on the Helium tunnel running at Mach 50, BTW.