Wingtip vortices stream from an F-15E as it disengages from a KC-10 Extender following midair refueling.

Wingtip vortices are regions of high vorticity which develop at the tip of a wing as it flies through the air (or potentially another fluid). Wingtip vortices are a form of induced drag, an essentially unavoidable side-effect of the wing generating lift. Designing a wing with a vortex of preferable shape is critically important in aerospace engineering. Wingtip vortices also form the major component of wake turbulence. Download high resolution version (1960x3008, 2052 KB)Wingtip vortices are visible trailing from an F-15 as it desengages from midair refueling with a KC-10 Extender during Operation Iraqi Freedom. ... Download high resolution version (1960x3008, 2052 KB)Wingtip vortices are visible trailing from an F-15 as it desengages from midair refueling with a KC-10 Extender during Operation Iraqi Freedom. ... See F-15 Eagle for main F-15 page. ... The KC-10 Extender is an air-to-air tanker aircraft in service with the United States Air Force derived from the civilian DC-10-30 airliner. ... Vortex created by the passage of an aircraft wing, revealed by coloured smoke A vortex (pl. ... Vorticity is a mathematical concept used in fluid dynamics. ... The wing tip of a Quad City Challenger II, formed with an aluminum bow The wing tip of an American Aviation AA-1 Yankee, showing its Hoerner style design A Piper PA-28 Cherokee with huge winglets installed The wing tip is that part of the wing most distant from... A Laughing Gull on the beach in Atlantic City, USA. Wing shapes: a swept wing KC-10 Extender from Travis Air Force Base, California, refuels a delta wing F/A-22 Raptor. ... In aerodynamics, lift-induced drag, or more simply, induced drag, is a drag force arising from the generation of lift by wings or a lifting body during flight. ... Aerospace engineering is the branch of engineering that concerns aircraft, spacecraft, and related topics. ... Wake turbulence, also known as jetwash, is turbulence that forms behind an aircraft as it passes through the air. ...

Cause and effects

As a wing flies through the air, it generates aerodynamic lift by creating a region of higher air pressure beneath the wing than above it, among other factors like air deflection for instance. It must be kept in mind that lift is a sum of forces not a single force. Fluids are forced to flow from high to low pressure and the relatively high pressure air below the wing tends to escape to the top of the wing. The air does not escape around the leading or trailing edge of the wing due to airspeed, but it can flow around the tip. Consequently, air flows from below the wing and out around the tip to the top of the wing in a circular fashion. This leakage will raise the pressure on top of the wing and lower the overall lift that the wing can produce. It also produces an emergent flow pattern with low pressure in the center surrounded by fast moving air with curved streamlines. The lift force, lifting force or simply lift consists of the sum of all the fluid dynamic forces on a body perpendicular to the direction of the external flow approaching that body. ...

Wingtip vortices only affect the portion of the wing closest to the end. Thus, the longer a wing is, the smaller the affected fraction of it will be. As well, the shorter the chord of the wing, the less opportunity air will have to form vortices. This means that for an aircraft to be most efficient, it should have a very high aspect ratio. This is evident in the design of long-range airliners and gliders, where fuel efficiency is of critical importance. However, increasing the wingspan reduces the maneuverability of the aircraft, which is why combat and aerobatic planes usually feature short, stubby wings despite the efficiency losses. Cross section of an airfoil showing chord In reference to aircraft, chord refers to the distance between the front and back of a wing, measured in the direction of the normal airflow. ... The low aspect ratio wing of a Piper PA-28 Cherokee In aerodynamics, the aspect ratio is an airplanes wings span divided by its standard mean chord (SMC). ... An Airbus A340 airliner operated by Air Jamaica An airliner is a large fixed-wing aircraft with the primary function of transporting paying passengers. ...

Another method of reducing fuel consumption is use of winglets, as seen on a number of modern airliners such as the Airbus A340. Winglets work by forcing the vortex to move to the very tip of the wing and allowing the entire span to produce lift, thereby effectively increasing the aspect ratio of the wing. Winglets also change the pattern of vorticity in the core of the vortex pattern; spreading it out and reducing the kinetic energy in the circular air flow, which reduces the amount of fuel expended to perform work by the wing upon the spinning air. Winglets can yield very worthwhile economy improvements on long distance flights. The McDonnell Douglas MD-11 was the first mainline airliner to feature winglets. ... The Airbus A340 is a long-range four-engined widebody commercial passenger airplane manufactured by EADS (Airbus S.A.S.). It is similar in design to the two-engined A330. ...

Since vortices cause a low-pressure area at their centre, sometimes water precipitates out to form clouds in the vortex cores, allowing wingtip vortices to be seen. This is most common on aircraft flying at high angles of attack, such as fighter aircraft pulling high G manoeuvres, or airliners landing. In this diagram, the black arrow represents the direction of the wind. ... The nominal acceleration due to gravity at sea level on the Earths surface, also known as standard gravity, is defined as exactly 9. ... An Airbus A340 airliner operated by Air Jamaica An airliner is a large fixed-wing aircraft with the primary function of transporting paying passengers. ...

Hazards

A NASA study on wingtip vortices produced these pictures of smoke in the wake of an aircraft, clearly illustrating the size and power of the vortices produced.

Wingtip vortices can also pose a severe hazard to light aircraft, especially during the landing and take off phases of flight. The intensity or strength of the vortex is a function of aircraft size, speed, and configuration (flap setting, etc.). The strongest vortices are produced by heavy aircraft, flying slowly, in a clean configuration; large jet aircraft can generate vortices which are larger than an entire small plane. These vortices can persist for several minutes, drifting with the prevailing wind. If a small plane is immediately preceded by a large aircraft on the runway, there is a high risk that the winds in a vortex will cause uncontrollable and sudden variations in altitude, possibly violently slamming the aircraft into the ground without warning. Worse, the circular nature of vortices can flip a small plane upside down. At the low altitudes involved with landing and takeoff, this is completely unrecoverable. The hazardous aspects of wingtip vortices are most often discussed in the context of wake turbulence. Image File history File links Download high resolution version (2976x2420, 995 KB) Date 05. ... Image File history File links Download high resolution version (2976x2420, 995 KB) Date 05. ... For other uses, see NASA (disambiguation). ... Mytravel Airbus A320 landing Landing is the last part of a flight, where a flying animal or aircraft returns to the ground. ... A Ryanair Boeing 737 takes off from Bristol International Airport, England Take off is the phase of flight where an aircraft transitions from moving along the ground (taxiing) to flying in the air (see flight), usually from a runway. ... Jet aircraft with condensation trail Jet aircraft are aircraft with jet engines. ... Runway 13R/31L of El Dorado International Airport, Bogotá, D.C., Colombia. ... Altitude is the elevation of an object from a known level or datum. ... Wake turbulence, also known as jetwash, is turbulence that forms behind an aircraft as it passes through the air. ...

External links

Wikimedia Commons has media related to:

Wingtip vortices

• Video from NASA's Dryden Flight Research Center tests on wingtip vortices:
  • C-5 Galaxy: [1]
  • Lockheed L-1011: [2]
• Wind prediction for analysis of vortex drift
• flares released by an air force jet