# Tag Info

### Can gliders and single-engine planes have vortices?

Vortices have rotational energy which comes from propulsion. This additional requirement of "Thrust" can be balanced with Induced drag. The "vortices" in question are generated by ...
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### How and why do wake vortices come together to form two tip vortices?

The picture in your question is an oversimplification. Maybe this photo of an MD-11 on a moist day will help to illustrate the point: I also think you should not call the wake vortices "tip vortices"....
• 233k
Accepted

### What is the role of a bound vortex?

I'll use the following diagram for illustration: Intuitively, a hard surface resists fluid flow via shear stresses; these shear stresses tend to rotate fluid elements (i.e. vorticity). Therefore, we ...
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### Are there any aircraft with retractable vortex generators?

Bell Textron filed a patent for retractable vortex generators in 2006. The patent is here. Boeing also filed a patent for vortex generators that extend simultaneously with a leading edge slat here.
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### Can wingtip vortices formed around an unswept wing produce vortex lift?

Vortex at straight wing has very small contact area with wing and also at wrong position. Vortex has low pressure, you can see blue color on upper surface where vortex touch surface. This part of ...
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### Can gliders and single-engine planes have vortices?

The aerodynamics can be explained, something I cannot do for that quote. Let's address the quote story first and, once that's out of the way, let's have a look at the aerodynamics. Wonky Quote ...
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### Can wingtip vortices formed around an unswept wing produce vortex lift?

The picture you've chosen of a water tunnel test at Onera nicely shows how the vortices generated at the leading edge of the delta wing wash over its upper surface and coalesce to form two big ...
• 13k

### What's the shape and place of the tip vortex in a propeller, depending on propeller sense of turning?

I too am unsure exactly what your question is but propeller blades shed vortices at the tips just like wings and rotor blades. This vortices and their paths can be seen when the weather conditions are ...
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### How and why do wake vortices come together to form two tip vortices?

You have to think of where pressure is lowest and where it is highest. The wing is forcing air downward along its entire span, creating a low pressure area above the wing and high pressure below it. ...
• 28.6k
Accepted

### Are there any aircraft with retractable vortex generators?

From my research on them, when used as a "poor man's slat" along the top of the leading edge, that is, to increase stalling AOA (about 1/3 to 1/2 the effect of a slat) and make the stall more gentle, ...
• 132k
Accepted

### Velocity induced by a straight vortex filament

You need to think in 3D. A vortex will induce a flow speed everywhere. That is the point 𝑃 lies in the plane containing the flow induced by the vortex at 𝑂 Why would you think that vorticity ...
• 233k
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### How does a shear layer make vortices?

A shear layer is no different than a boundary layer. Except both sides are a fluid vs. fluid/solid. And usually we choose a reference frame that has the solid frame at zero velocity -- and ...
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### Where are the vortices from the trailing edge on the wing of a plane?

The vortex you're thinking about is what we call the 'startup vortex' It is shed when the circulation changes -- the largest such change is when you go from rest to impulsively starting a lifting low....
• 12.6k
Accepted

### Flow separation in inviscid flow

Euler CFD solutions are subject to something called artificial (or numerical) viscosity. How much you have depends on whether your method is odd or even order -- dictating whether a diffusive or ...
• 12.6k
1 vote

### Flow separation in inviscid flow

This is a well known phenomenon, a Kármán vortex street. Wikipedia explains it adequately. I won't quote that entire article, though, daring for now to post a link-only answer.
• 11.9k
1 vote

### Why do flat wings create a vortex/vortices?

At a sufficiently high angle of attack, a rectangular thin-plate "airfoil" suffers flow separation at its upper surface, just like any conventional airfoil would. (A thin plate is not at all ...
• 11.9k
1 vote
Accepted

### How do 2 vortices (or more) combine when they are near each other?

You can linearly combine the speeds caused by vortices. This can create constructive or destructive interference; this means the speeds induced by either one can either add up or cancel with those of ...
• 233k
1 vote

### Can wingtip vortices formed around an unswept wing produce vortex lift?

The vorticity behind a wing is only a consequence of what happened before above and below the wing, but cannot alter the wing's lift or drag in any way. I remember a breathless report of an ultralight ...
• 233k
1 vote

### Why does the leading edge vortex accelerate the flow downward?

It is the inclination of the wing which forces the air flowing over it downwards. This is very much like when you hold your stretched-out hand out of a car's window and into the airstream and then ...
• 233k
1 vote

### How do wing tip vortices that interact with the wing surface affect drag?

What we commonly call wingtip vortex is technically not a vortex in the strict sense. The spiraling circulating air around the wing tip that trails behind the wing is actually the product of two ...
• 11.1k
1 vote
Accepted

### How does vorticity change the lift coefficient of an airfoil?

Shed vortices from unsteady flow over an airfoil result in decrease and phase lag in lift. Ref: https://www.researchgate.net/figure/Vortex-shedding-from-an-airfoil-oscillating-in-pure-heave-...
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1 vote

### Does an aircraft with higher aspect ratio wings produce more wingtip vortices in a turn than one with lower aspect ratio wings?

The strength of a wingtip vortex depends on the span loading of the wing, so both weight and wingspan matter. A turn increases the apparent weight but does not change the comparison between aircraft. ...
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1 vote

### Does an aircraft with higher aspect ratio wings produce more wingtip vortices in a turn than one with lower aspect ratio wings?

Easy to follow diagramFor two wings with the same area, the higher AR wing will produce LESS wingtip vortices simply because there is not as much area close to the wing tip that can be affected by the ...
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1 vote

### What aspect ratio is best for Wind Tunnel Testing an aerofoil with Small Additives?

What is it you want to test? Do you want to test the 2D characteristics of an airfoil? Then make it the width of the windtunnel. The wind tunnel walls act like mirrors, so you will have the behaviour ...
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