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."

Comments

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:007 Bird Agent

[dimator]

Such a device would be terrible for living birds. Can you imagine an enemy camp shooting every flying bird that comes close with a bazooka for fear of one of these devices?

If you can make a bird "spy" thingy, then you could make it into other animals too, and soon the baddies would literally be shooting anything that moves.

Re:007 Bird Agent

[Kerg]

Or...

You could build an army of nano robots that look like ants. Those little critters can get anywhere. You could hide a whole bunch of them in bin Laden's beard.

Re:007 Bird Agent

[greenrd]

Just think of the hidden cam porn possibilities... yum!!

Why Tilt the Whole Thing?

[dragons_flight]

I can understand wanting different angles of flight, but why do you have to tilt the whole aparatus? It would seem that being able to tilt the whole wind tunnel would be a rather difficult (ie expensive) engineering constraint.

Is there a good reason you couldn't work out some sort of flexible tubing or other solution so that part of the tunnel could be bent appropriately without moving the whole thing? Would the effect on the air flow be so disruptive that you couldn't correct for it?

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.

Eagles

[Black Parrot]

One of the most interesting things I ever saw in a nature flick was a clip of an eagle grabing a big fish out of a lake. The fish was so big that the eagle was only able to gain altitude very slowly.

But the interesting thing was the way the eagle handled the fish. It came up from the water with the fish turned sideways in its two feet, but over a period of several seconds it shuffled its grip on the fish and turned it pointing forwards, the way a fish swims in the water -- presumably to reduce the aerodynamic drag on it.

Re:Eagles

[nomadic]

Sometimes birds miscalculate; ospreys have been known to dive into the lake, grab a fish, then have it drag them under. Then fisherman catch the fish and wonder why there's remnants of a bird skeleton embedded in the fish...

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.

Compliance

[Engelbot]

Well, *my* wind tunnel is 100% OpenSwallow 2001 compliant, and supports remote control through /dev/windtunnel. :-)

Re:Compliance

[Morbid Curiosity]

Well, *my* wind tunnel is 100% OpenSwallow 2001 compliant, and supports remote control through /dev/windtunnel. :-)

There was a Microsoft development that attempted to rival the OpenSwallow development. However, since Microsoft doesn't practice full disclosure of bugs, the insectivorous swallows couldn't catch them and starved. Quite tragic.

Still, there is a moral to the story: Microsoft sucks; Open Source swallows.

MRI

[threaded]

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.

What, no benchmarks?

[Anonymous Coward]

And all this time, I was hoping to see the effect it has on rfc1149 throughput.

An 'excercise bike' for homing pigeons

[DABANSHEE]

I wonder if people racing pigeons will buy these for pigeon training.

Improvements in man-made wings possible?

[imrdkl]

The article discusses the design and history of the wind-tunnel at length. They seem pretty proud of it. Thats cool. They also talk about trying to learn about how much energy is used by migratory birds on long flights. Thats also cool. I guess (IANABiologist) that the distance that some species, like the albatross, fly without food is pretty amazing.

Whats interesting for me tho, is what can be learned about wing design from these birds. I don't know if a wing that really "flaps" could ever be used, but surely there must be some good "science" in the flow patterns which can be observed from a large wing in a "glide" setting. Although I doubt the tunnel is big enough for an albatross...

Anyways, interesting science from the Swedes.

Re:Improvements in man-made wings possible?

[dhogaza]

We actually know more about albatrosses than birds which flap energetically - an albatross flies similarly to a fixed-wing aircraft when conditions are right. This is one reason they're able to fly such long distances with such little nourishment. Among other things the wings can more or less lock in place, meaning that most of the energy expended by the bird goes to controlling angle and pitch etc in order to steer (tail plays a role, too, of course).

Flapping flight, though, that's whole 'nother thing and not analogous to either fixed-wing aircraft or helicopters.

Re:Improvements in man-made wings possible?

[dhogaza]

An interesting finding made by these guys that I didn't see mentioned on the site is in regard to flight efficiency in migratory shorebirds.

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.

One experiment goes horribly wrong...

[Crag]

Scientist #1: OH MY GOD! The tunnel is coming apart!

Scientist #2: DUCK!

Re:horrible

[pacc]

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

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.

The greates contribution to mankind will be..

[marcelk]

Given that this machine recycles its
airflow, it provides a good training
for these birds not to shit during flight.

science of flight book

[danny]

A nice popular work on flight is Hank Teneke's The Simple Science of Flight . One thing I particularly liked about this is that it treats birds (and insects) alongside aircraft.

Danny.

OH great!

[G00F]

Something else my bird will want for christmass! Everyear fancier toys, and new ways to advertise it. . . .

Our greatest weapon...

[neema]

Don't be fooled! This is all weapon research to be used on the "War against Terrorism". The bird cannon will devastate millions!

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.

Paging Mr. Seagull....

[wowbagger]

Sir, I have a proposal here for some experiments in our bird wind tunnel. Experiments on top speed, stall speed, and acrobatics.

Sounds interesting. Who's the request from?

A Mr. Seagull. Jonathan Livingstone Seagull.
</Humor>

Re:Smart Birds?

[dhogaza]

Ha! Airplanes have engines! If "that" (gliding) is what airplanes do, they'd be called "gliders" and they wouldn't have "engines" (nor would you take one coast-to-coast except on days with *exceptional* thermal activity - and you'd never take one across the Pacific).

Hint - the engines are those big things hanging down from the wing, usually one or two to a side. Another hint - don't stand in front of them when they're revved up to take-off power!

Link to an article

[CTho9305]

Here is one of many: Just search google for "toast butter down".

Re:Link to an article

[jesser]

Detailed calculations of the dynamics of tumbling toast confirmed my suspicions, and revealed something else: that the presence of butter was more or less irrelevant. Neither its weight nor aerodynamic properties had much effect on how toast landed. The crucial factor is purely height - and toast sliding off a plate spins so slowly that only if it falls from heights above 8ft does it have much hope of regularly landing butter-up.

Does that mean the Zooks has it right after all? And to think we, the Yooks, almost bombed them into oblivion for eating their toast butter-side down.

Re:Ralph Kramden's Golf Game

[Buran]

Birds can be acclimated to the presence of people. In falconry, this is called "manning" a bird (nothing to do with spacecraft carrying people). I visited the World Bird Sanctuary here in St. Louis a few weeks ago (pictures are in here) and few of the birds I looked at were afraid of people. There are even a few photos on the net -- I went with friends -- of some of us standing next to some large raptors that I could almost say posed for the camera!

It's similar to the way stray cats that are mistreated will often be afraid of the new owners who take them in but over time lose their fear (one of the cats we had when I was a child was named 'Fraidy Cat' for this reason, which later became 'Fred E. Cat') ...

Re:Kinda Cruel

[Raven42rac]

I get the "kinda cruel" part because the dog is not truly out in the wilderness, nor is the bird flying through the air. Animals are not stupid, they sense when they being held as a prisoner.