How the Hummingbird Achieves its Aerobatic Feats The most detailed,3D aerodynamic simulation of hummingbird flight conducted to date has definitively demonstrated that the hummingbird achieves its nimble aerobatic abilities through a unique set of #aerodynamic #forces that are more closely aligned to those found in flying #insects than to other birds. >>The new realistic supercomp fluid dynamic simulation shows they make use of #unsteady #airflow mechanisms, generating invisible #vortices of air that produce the lift they need to hover and flit from flower to flower. ie #lift production is much #trickier than beating its wings fast enough and hard enough it can push enough air downward eg as the bird pulls its wings forward and down, tiny vortices form over the leading and trailing edges and then #merge into a single large vortex, forming a #low-pressure area that provides lift. In addition, the tiny birds further enhance the amount of lift they produce by #pitching up their wings (rotate them along the long axis) as they flap. >>Hummingbirds perform another trick - one that sets them apart from their larger bird relatives. They not only generate +ve lift on the #downstroke, but they also generate lift on the #upstroke by inverting their wings. As the leading edge begins moving backwards, the wing beneath it rotates around so the top of the wing becomes the bottom and bottom becomes the top. This allows the wing to form a #leading edge vortex as it moves backward generating positive lift. >>The downstroke produces most of the thrust but that is only because the hummingbird puts more energy into it. The upstroke produces only 30% as much lift but it takes only 30% as much #energy, making the upstroke equally as aerodynamically efficient as the more powerful downstroke. #Large birds, by contrast, generate almost all of their lift on the downstroke. news.vanderbilt.edu/2014/11/how-the-hummingbird-achieves-its-aerobatic-feats/
Posted on: Sat, 22 Nov 2014 17:39:08 +0000
Trending Topics
Recently Viewed Topics
© 2015