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Old 11-13-2015, 03:32 PM   #11 (permalink)
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Hey! We are out of paper towels! Crank up the wind tunnel!

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Old 11-13-2015, 08:30 PM   #12 (permalink)
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Quote:
Originally Posted by Cd
So does this also mean a lower power draw when doing the testing ?
Wind tunnels are huge power hogs.
No indication of how high the ceiling is, but that's a scale 5 lanes wide. The Darko wind tunnel OTOH has a cross-section more like a carport.

I suspect the cost to run the tunnel is the same with or without anything being tested.
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Old 11-14-2015, 04:23 PM   #13 (permalink)
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Hey! We are out of paper towels! Crank up the wind tunnel!
That would be a feature of the Dyson wind tunnel.
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Old 11-16-2015, 01:05 PM   #14 (permalink)
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Are they increasing the air pressure in the tunnel? Or do they just multiply the air speed to compensate for the scale of the models?
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Old 11-16-2015, 05:34 PM   #15 (permalink)
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tunnel air speed

I don't have my calculator,but I'm thinking that at 40%-scale,they'd run about 50-mph airspeed to simulate 20-mph at full-scale.Otherwise the Reynolds number wouldn't be high enough to transition the boundary layer.
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Old 11-16-2015, 05:35 PM   #16 (permalink)
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Quote:
Originally Posted by freebeard View Post
No indication of how high the ceiling is, but that's a scale 5 lanes wide. The Darko wind tunnel OTOH has a cross-section more like a carport.

I suspect the cost to run the tunnel is the same with or without anything being tested.
I noticed that too. You could fit a full size car in that thing.
I really do hope it is more efficient.
Large wind tunnels use several MEGAWATTS of electricity.

I seem to remember ( was it Aerohead ?) someone posting that when some of these large scale / supersonic tunnels are powered up, the lights used to dim in the area, due to the power draw !
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Old 11-16-2015, 05:59 PM   #17 (permalink)
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ceiling height

At the article website there are a number of photos of the tunnel.
One shows Nina crouching at the tunnel nozzle jet with smoke wand and model.You can see that the nozzle is probably only as tall as Nina.
The test section is 'open' and enormous,but the model is only occupying no more than 5% of the jet cross-sectional area.(outlined in blue)
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Old 11-16-2015, 06:14 PM   #18 (permalink)
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Why is it that most tunnels are in a huge room ( the University of Toronto, and the one that Ford has come to mind ) and others like the DARKO and A2 are in a small car port sized tunnel ?
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Old 11-16-2015, 06:53 PM   #19 (permalink)
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Why is it that most tunnels are in a huge room ( the University of Toronto, and the one that Ford has come to mind ) and others like the DARKO and A2 are in a small car port sized tunnel ?
There are a number of tunnel designs and each has specific merits.
A large,open test section allows a lot of maneuvering near the jet,plus low blockage ratios,and the ability to yaw the vehicle.
For straight up drag measurements,as long as buoyancy factors,and boundary layer thickness is addressed,smaller,less expensive tunnels (Pinifarina for example) can return drag and lift data as accurately as the 'monster' tunnels.
1,800-hp is a lot cheaper to run than 18,000-hp or more.
Hucho has an entire chapter devoted to tunnels.
Alan Pope's ,book,'Low Speed Wind Tunnel Design' goes into detailed design.
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Old 11-16-2015, 08:43 PM   #20 (permalink)
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You can compare the new tunnel to the full size tunnel in Google Maps...

Google Maps of tunnels

New tunnel is on the left.

Link work?

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