Vortex generator

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Image:Cessna182withVotexGenerators02.jpg
1967 Model Cessna 182K in flight showing after-market vortex generators on the wing leading edge
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After-market Micro Dynamics vortex generators mounted on the wing of a Cessna 182K
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The Symphony SA-160 has two unique vortex generators on its wing to ensure aileron effectiveness through the stall

A vortex generator is an aerodynamic surface, consisting of a small vane that creates a vortex. They can be found in many devices, but the term is most often used in aircraft design.

Vortex generators are added to the leading edge of a swept wing in order to maintain steady airflow over the control surfaces at the rear of the wing. They are typically rectangular or triangular, tall enough to protrude above the boundary layer, and run in spanwise lines near the thickest part of the wing. They can be seen on the wings and vertical tails of many airliners. Vortex generators are positioned in such a way that they have an angle of attack with respect to the local airflow.

A vortex generator creates a tip vortex which draws energetic, rapidly-moving air from outside the slow-moving boundary layer into contact with the aircraft skin. The boundary layer normally thickens as it moves along the aircraft surface, reducing the effectiveness of trailing-edge control surfaces; vortex generators can be used to remedy this problem, among others, by re-energizing the boundary layer. Vortex generators delay flow separation and aerodynamic stalling; they improve the effectiveness of control surfaces (e.g Embraer 170 and Symphony SA-160); and, for swept-wing transonic designs, they alleviate potential shock-stall problems (e.g. Harrier, Blackburn Buccaneer, Gloster Javelin).

Many aircraft carry vane vortex generators from time of manufacture, but there are also after-market suppliers who sell VG kits to improve the STOL performance of some light aircraft.

Air jet vortex generators work on a different principle. They direct a jet of air into the boundary layer, thereby re-energising it.

Vortex generators are also being used in automotive vehicles. In one form they are used as in aircraft to influence the boundary layer of air flow primarily for drag reduction. In another form they are installed in the engine's air intake hose. Manufacturers claim that the vortex generator creates a swirling motion within the air intake pipe, and within the combustion chamber causing improved burning of the fuel, increasing horsepower and fuel efficiency.

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