Wind Tunnel for Birds

bgood writes "'What, a swallow, carrying a coconut? ...' The Department of Animal Ecology at the University of Lund in Sweden uses a modern low-speed wind tunnel specially crafted for bird experiments. The birds are trained to fly in the 'test-section' and the tunnel can be tilted up or down to simulate ascent and descent. This link contains plenty of detail, complete with bird pictures. For those of you who yearn to build your own (non-bird-compliant) wind tunnel, you can find instructions in this Scientific American article."

007 Bird Agent

[TilRock]

This could prove to be very useful in figuring out how to build a flying robot that mimics a real bird. You could fly one of these things behind enemy lines, undetected, and spy on damn near anything you want as close as you want. Pretty far off in the future yet but a definate possibility.

Re:Smart Birds?

[mutende]

I'd imagine that the birds would eventually figure out that they can just glide and not have to flap their wings? I mean isn't that what airplanes do?

Only if the bird flies ``downhill''. A quote from the page:

The experimenter can control the wind speed and set it to a speed appropriate for the bird species in question. He can also tilt the whole tunnel, so that the wind is inclined upwards or downwards, relative to the horizontal (+8 to -6 degrees). If the wind is inclined upwards, the bird is effectively flying "downhill". If the angle is steep enough, the bird can glide without flapping its wings.

Re:Why Tilt the Whole Thing?

[Anonymous Coward]

The problem may be that you always want the wind to be travelling parallel to the sides of the tunnel. If it is not, then you will set up turbulene due to the wind bouncing off the sides.

So, changing wind direction may actually make it a much more complicated environment w.r.t the bird.

I've seen worse

[candyuk]

Loughborough University Physics Department received a grant of £250K (about $400K) to investigate the aerodynamics of Toast, and to find out why toast lands butter side down no matter what height you drop it from. Hey investigating bird flight with a wind tunnel sounds quite good.

Re:Why Tilt the Whole Thing?

[Anonymous Coward]

Angle of attack w.r.t gravity doesn't really enter into it. The "angle between" gravity and the wind is independent of the mechanism by which the wind is generated.

Consider the following:
1) Tilting the tunnel at 45 degrees
2) Generating wind at a 45 degree angle within the tunnel using a moveable source.

There are 2 frames of reference - inside the tunnel and outside the tunnel.

The angle that the wind is blowing is constant w.r.t the outside of the tunnel. Therefore in both cases the angle between gravity and the wind is the same. The angle between the wind and the tunnel, however, is different. I suspect that this may be the main rational between the approach to changing the angle of attack.

(Or, I could be on crack. :-) )

Re:What about the noise?

[Knobby]

Uhm.. Not all tunnels are loud. I imagine this tunnel is only running at 10-20mph.. At those speeds the aeroaccoustic noise should be very minimal (Noise is proportional to Velocity^4).. Assuming the motor is sized correctly, well balanced, and turning an aerodynamically clean fan, the noise levels should be very small in the test section..

I'm actually surprised they decided to use a closed loop facility for a study like this. The cost of a closed loop facility is roughly 2.5 times the cost of an open loop facility (all those turning vanes should be airfoils) and there are air exchange issues to deal with..

interesting project though.

Link to an article

[CTho9305]

Here [smh.com.au] is one of many: Just search google for "toast butter down".