The selected main airfoil is adapted from Liu, 27,28 where they use a 3D laser scanner to measure the wing surfaces of mergansers and seagulls. Haecheon Choi, the corresponding author of the paper. The geometry of airfoil is based on the previous study of bird wings and alula.
The role of the alula in avian flight is just one example." says Dr.
#Alula wing full#
"Nature is full of vortices, and the animals and plants use them wisely. But this is the first time that the researchers found the evidence that the effect of the alula is due to a small vortex formed at the tip of the alula feathers. There have been several other attempts to reveal the role of the alula in birds' flight. A similar appendage beneath each elytron of. In entomology: The small membranous appendage or scale situated at the base of each wing of many dipterous insects, above the halteres or poisers. Measurements of the forces acting on wings in the wind tunnel proved that indeed the presence of the vortex from the alula helps the birds in flight. In ornithology, the winglet, bastard wing, or ala spuria of a bird the packet of small feathers which grows upon the so-called thumb of a bird's wing. Although the alula is small, it creates enough vortex to prevent the air flow from being detached from the wing." says Dr. "For the wing to fly better, the air has to move closer to the wing. The alula is the freely moving first digit, a bird's 'thumb,' and is typically covered with three to five small feathers, with the exact number depending on the species. Here they observed that a tiny vortex from the alula tip presses the air flow over the wing and makes the air flow better attached to the wing surface. The alula, or bastard wing, is a small projection on the anterior edge of the wing of modern (and some ancient) birds. Then the researchers moved on to the wind tunnel experiments where they visualized the movement of tiny particles around magpie wings. "But with the alula they seem to turn more easily." Sang-im Lee, the first author of the paper. When flying at slow speeds or landing, bird moves alula upwards and forwards, which creates a. "It's not that they cannot fly without the alula." says Dr. The alula is held flush against the wing but it can be moved. They started with observing magpies in the aviary when the birds moulted the alula feathers. The researchers were interested in the flight of magpies. This study was conducted by a research team of biologists and mechanical engineers at the Seoul National University. A recent article published in Scientific Reports says that the secret is a small vortex of air that is formed at the tip of the alula feathers.
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