Science

Scientists unlock the secrets of flying dandelion seeds

Scientists unlock the secrets ...
The researchers think the discovery could inform the design of tiny airborne drones
The researchers think the discovery could inform the design of tiny airborne drones
View 6 Images
The separated vortex ring can be seen in the right-hand image
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The separated vortex ring can be seen in the right-hand image
The researchers' vertical wind tunnel
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The researchers' vertical wind tunnel
The team used X-ray imaging and microscopes to examine the morphology of dandelions
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The team used X-ray imaging and microscopes to examine the morphology of dandelions
The team used X-ray imaging and microscopes to examine the morphology of dandelions
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The team used X-ray imaging and microscopes to examine the morphology of dandelions
Stacked dandelion seeds analyzed by the team
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Stacked dandelion seeds analyzed by the team
The researchers think the discovery could inform the design of tiny airborne drones
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The researchers think the discovery could inform the design of tiny airborne drones

Carried by the wind, dandelion seeds can travel enormous distances of more than a kilometer (0.6 miles). Now, researchers at The University of Edinburgh have discovered that this is thanks to a remarkable form of flight never before seen in nature.

The distances are achieved because of what the researchers call "the separated vortex ring" which sees the seed bristles, collectively called the pappus, create ring-shaped air bubbles. These form vertically above the pappus, increasing air-resistance and slowing descent much like a parachute.

Remarkably, the air bubble is actually made more stable as air flows through it. And that flow is regulated by the particular spacing of the seed's bristles. Perhaps counter-intuitively it's the relatively high porosity of the pappus that helps keep its flight stable.

The separated vortex ring can be seen in the right-hand image
The separated vortex ring can be seen in the right-hand image

Above: The separated vortex ring can be seen in the right-hand image

To analyze the seeds, the team built a vertical wind tunnel honed such that the seed would hover at a sustained height. The researchers used a mixture of long-exposure photography and high-speed imaging to analyze the flow of air through and around the pappus. They also used X-ray imaging and microscopes to examine the morphology of the dandelions themselves.

According to the researchers the dandelion's seeded form is four times more efficient in maintaining altitude than a human-made parachute.

Though dandelion seeds can travel more thank 1 km, they typically land within 2 meters (6.6 feet) of the flower. However, the seeds of other flowers in the Asteraceae, which also includes daisies and sunflowers, can disperse more than 150 km (93 miles).

The researchers speculate that this form of travel could inform the design of tiny airborne drones which require no power supply and that could, say, monitor air pollution.

The team's research, A separated vortex ring underlies the flight of the dandelion, was published in the journal Nature.

Source: The University of Edinburgh

4 comments
MD
Yes BUT can it (a human made one) be packed inside a "backpack" and deployed at will... Or does it have to Grow? Hopefully we will be able to replace Parachutes with Dandelion down before too long....
edjudy
" . . . never before seen in nature." Huh? :-) I first remember seeing this form of flight sometime in about 1954 . . . and that's just me. I'm thinking this form of flight has been observed for centuries . . . though it is just now being described in technical detail. :-)
nehopsa
"tiny airborne drones which require no power supply and that could, say, monitor air pollution." ....ubiquitous surveillance micro drones one step closer to reality (,say, monitor air pollution)
Nik
The distance travelled by a dandelion seed, 'gustimated' as one km, when released is probably an underestimate. It must be dependent on wind and terrain, and location within that terrain. If the seed was released on a hilltop, with a strong wind, then it could conceivably travel several miles, like hang gliders, that also launch from hilltops. The same hill could produce an upward draught, that could lift the seeds well above the hill, and so travel longer distances. In addition, if the ground was bare of vegetation, as in a farmers field, the seed could be blown further, even after landing. I doubt that the dandelions 'parachute' could be scaled up to carry a human however, at least not with presently available materials.