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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."
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.
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.
Well, *my* wind tunnel is 100% OpenSwallow 2001 compliant, and supports remote control through /dev/windtunnel. :-)
This method only displays the surface information.
If they could fix up an MRI (Magnetic Resonance Imaging) machine they could also get information on muscle use and blood flow.
Now that would be neat.
threadeds blog
And all this time, I was hoping to see the effect it has on rfc1149 throughput.
Scientist #1: OH MY GOD! The tunnel is coming apart!
Scientist #2: DUCK!
It's not horrible, the scientists using it said that they haven't even let a bird fly more tahn two days in a row, because they had to go home and sleep themselves. (Feature on Swedish Television "Nova")
In context, they didn't even get close to the birds limits flying 3000 km without stop in 3 days, with species reaching over 10000 km.
The bird themselves flies these distances in the wild and would have suffered more if held in captivity withouth the chance to get rid of the summer fat.
In the spring they are released again in their natural environment.
What interest the scientists is how the birds can manage to eat its own weight in a single day, and be able to use that energy to build up muscles extremely fast, and then use it up during the flight.
Some reference in Swedish
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.
As someone mentioned above, shorebirds have an amazing ability to pig down and generate a lot of muscle and fat in a very short period of time (a large fraction of their body weight in 24-48 hours).
So - are they more efficient when their tank's full or empty, i.e. heavy after "refueling" or light as after a long stint in the air (they're known to migrate hundreds of miles between stops).
The reference I saw a few days ago says the answer, measured in this wind tunnel, is that they're more efficient when their tank's full (so to speak).
The studying of the physiology of migratory shorebirds may be important for conservation, too. There are generally limited areas in which shorebirds concentrate to feed on migration. While some migrate inland, in many species virtually all individuals migrate along the coast. And, of course, in most parts of the world coastal areas are under heavy developmental pressure. People like the beach, too...
Examples of such concentration areas include Delaware Bay in the eastern United States and Bowerman Basin in the western US.
And human use of natural resources also has an impact (in particular the harvesting of horsehoe crabs on the east coast, they're the source of some important chemical but I forget what exactly - we don't eat them, obviously!)
More knowledge about the physiology of these species might help us predict the impacts of certain types of development or resource consumption.