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Search results for: “wingtip vortices”

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    Visualizing Wingtip Vortices

    At the ends of an airplane‘s wings, the pressure difference between air on top of the wing and air below it creates a swirling vortex that extends behind the aircraft. In this video, researchers recreate this wingtip vortex in a wind tunnel, visualized with laser-illuminated smoke. The team shows the progression from no vortex to a strong, coherent vortex as the flow in the tunnel speeds up. Along the way, there are interesting asides, like the speed where the honeycomb used to smooth the upstream flow is suddenly visibly imprinted on the smoke! (Video and image credit: M. Couliou et al.)

  • Visualizing Wingtip Vortices

  • Wingtip Vortices Visualized

    Wingtip Vortices Visualized

    In flight, airplane wings produce dramatic wingtip vortices. These vortices reduce the amount of lift a 3D wing produces relative to a 2D one. How much they influence the lift depends on both the strength and proximity of the vortex. The stronger and closer it is, the more detrimental its effect. One way airplane designers reduce the effects of wingtip vortices is by adding an extra section, called a winglet, to the end of the wing. Among other effects, the winglet moves the wingtip vortex further away from the main wing, which reduces its influence and allows the airplane to regain some of the lift that would otherwise be lost. (Image credits: A. Wielandt et al., source)

  • Wingtip Vortices

    Wingtip Vortices

    Wingtip vortices are the result of high-pressure air from beneath a wing sneaking around the end of the wing to the low-pressure area on top. They trail for long distances behind aircraft, and are, most of the time, an invisible hazard for other aircraft. If you’ve ever sat in a line of airplanes waiting to take off and wondered why there is so much time between subsequent take-offs, wingtip vortices are the answer. The larger a plane, the stronger its vortices are and the greater their effect on a smaller craft. Much of the time between planes taking off (or landing) is to allow the vortices to dissipate so that subsequent aircraft don’t encounter the wake turbulence of their predecessor. Crossing the wake of another plane can cause an unexpected roll that pilots may not be able to safely correct, a factor that’s contributed to major crashes in the past. (Image credits: flugsnug, source video; submitted by entropy-perturbation)

  • 4th Birthday: Wingtip Vortices

    4th Birthday: Wingtip Vortices

    Wingtip vortices are a result of the finite length of a wing. Airplanes generate lift by having low-pressure air travelling over the top of the wing and higher pressure air along the bottom. If the wing were infinite, the two flows would remain separate. Instead, the high-pressure air from under the wing sneaks around the wingtip to reach the lower pressure region. This creates the vorticity that trails behind the aircraft. I was first introduced to the concept of wingtip vortices in my junior year during introductory fluid dynamics. As I recall, the concept was utterly bizarre and so difficult to wrap our heads around that everyone, including the TA, had trouble figuring out which way the vortices were supposed to spin. A few good photos and videos would have helped, I’m sure. (Photo credits: U.S. Coast Guard, S. Morris, Nat. Geo/BBC2)

  • Wingtip Vortices

    Wingtip Vortices

    Newton’s third law says that forces come in equal and opposite pairs. This means that when air exerts lift on an airplane, the airplane also exerts a downward force on the air. This is clear in the image above, which shows a an A380 prototype launched through a wall of smoke. When the model passes, air is pushed downward. The finite size of the wings also generates dramatic wingtip vortices. The high pressure air on the underside of the wings tries to slip around the wingtip to the upper surface, where the local pressure is low. This generates the spiraling vortices, which can be a significant hazard to other nearby aircraft. They are also detrimental to the airplane’s lift because they reduce the downwash of air. Most commercial aircraft today mitigate these effects using winglets which weaken the vortices’ effects. (Image credit: Nat. Geo./BBC2)

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    Wingtip Vortices

    Any finite length wing produces wingtip vortices–potentially intense regions of rotational flow downstream of the wing’s ends. These vortices are associated both with the production of lift on the wing and with unavoidable induced drag. The tabletop demonstration above shows the region of the vortices’ influence and how strong the rotation is there. Note also that the two vortices have opposite rotational senses–the left side induces a clockwise rotation, whereas the right side induces an anti-clockwise rotation. The larger an aircraft, the stronger and longer lasting its vortices; this can be a source of danger for smaller aircraft passing through the wake. If a pilot crosses one wingtip vortex and overreacts to compensate, crossing the second counter-rotating vortex can cause even greater damage.

  • Wingtip Vortices in Ground Effect

    [original media no longer available]

    If you’ve ever watched airplane contrails fade, you’ve probably observed the Crow instability, which causes the trailing wingtip vortices of the plane to interact and distort. The same effect is explored in the video above with the addition of ground effect. The first clip shows a pair of counter-rotating vortices from the side, showing a periodic pattern of thickening and thinning along the vortices. The second clip shows cross-sectional slices of the vortices at a thin and a thick point.

  • Discovery Wingtip Vortices

    Discovery Wingtip Vortices

    Wingtip vortices mark the path of Discovery as she makes her final landing. Though not always visible, these vortices are generated by any lifting body planform and can be a major source of induced drag on the craft. Here the vortices are visible because the low pressure in the core of the vortex caused a local temperature drop below the dew point, thus causing condensation. Such vortices persist for significant lengths of time in the wake of aircraft; they are a major source of wake turbulence, which limits how frequently aircraft can take-off or land on a single runway. (Photo by Jen Scheer)

  • Wingtip Vortices in Ground Effect

    Wingtip Vortices in Ground Effect

    In this flow visualization, wingtip vortices from an aircraft have been simulated using an apparatus with a couple of flaps that snap together like a book closing. Dye is pooled on the “ground” below the flaps and gets entrained by the vortices and lit up using laser light. The red vortices are the primary vortex generated by the aircraft wingtips and the green ones are secondary vortices generated by interaction with the ground. The lower half of the picture is a reflection off the ground. This photo was part of the 2009 Gallery of Fluid Motion. #

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