Editing Vortex generator (section)

==Method of operation==
Vortex generators are most often used to delay [[flow separation]].  To accomplish this they are often placed on the external surfaces of vehicles<ref name="Clancy">Clancy, L.J. ''Aerodynamics'', Section 5.31</ref> and wind turbine blades. On both aircraft and wind turbine blades they are usually installed quite close to the leading edge of the [[airfoil|aerofoil]] in order to maintain steady airflow over the control surfaces at the trailing edge.<ref name="MicroHow"/> VGs are typically rectangular or triangular, about as tall as the local [[boundary layer]], and run in spanwise lines usually near the thickest part of the wing.<ref name="Peppler"/> They can be seen on the wings and vertical tails of many [[airliner]]s.

Vortex generators are positioned obliquely so that they have an [[angle of attack]] with respect to the local airflow<ref name="Peppler"/> in order to create a tip vortex which draws energetic, rapidly moving outside air into the slow-moving boundary layer in contact with the surface. A turbulent boundary layer is less likely to separate than a laminar one, and is therefore desirable to ensure effectiveness of trailing-edge control surfaces. Vortex generators are used to trigger this transition. Other devices such as [[vortilon]]s, [[leading-edge extension]]s, and [[leading-edge cuff]]s,<ref>A drooped leading edge presents a "vortex-producing discontinuity", in "Spin Resistance Development for Small Airplanes", SAE paper 2000-01-1691</ref> also delay flow separation at high angles of attack by re-energizing the boundary layer.<ref name="Peppler"/><ref name="MicroHow"/>

Examples of aircraft which use VGs include the [[ST Aerospace A-4SU Super Skyhawk]] and [[Symphony SA-160]]. For swept-wing transonic designs, VGs alleviate potential [[shock-stall]] problems (e.g., [[Hawker Siddeley Harrier|Harrier]], [[Blackburn Buccaneer]], [[Gloster Javelin]]).