Both of them prevent the aircraft from stalling, so is there any difference between them? The wing fence doesn't produce a vortex, so how does it work?

  • 3
    $\begingroup$ Several wing modifications $\endgroup$
    – mins
    Feb 13, 2016 at 22:43
  • 2
    $\begingroup$ A fence will create a vortex, just like a vortex generator, due to crossflow near the leading edge. All those devices (dogtooth, notch, fence, vortex generator) are working in the same way. Their difference is the shape. $\endgroup$ Feb 14, 2016 at 10:33
  • $\begingroup$ "prevent the aircraft from stalling" More like: reduces the airspeed at which the wing stalls (ex. 50 knots to 45 knots), or increases the AOA at which the wing stalls, or improves the handling of the aircraft at slow speeds. $\endgroup$
    – CrossRoads
    Aug 29, 2019 at 12:36

1 Answer 1


The wing fence is more or less what it is called- a fence. For swept wing aircraft, the local flow is not along the direction of flight, as there is a significant spanwise flow from the center towards the tips. It can be seen in the following figure.

Spanwise flow

Image from fuckyeahfluiddynamics.tumblr.com

The end result is that the boundary layer continues to grow (thicken) in this direction, with outboard regions more prone to stall than inboard ones. Basically, the wing fences stop the spanwise flow, with the result being a new (thinner) boundary layer starts on the other side of the fence.

In case of a vortex generator, the VGs basically create a vortex which re-invigorates the boundary layer by mixing free stream air with that of the boundary layer, thereby preventing separation.


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