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There is already a long series of questions about the downwash and tip vortexes with nice images, but I'm going to add another one...

Large airliners (A380, B747-8) have horizontal stabilizers competing with small Boeing wings, and definitely larger than business jet wings.

enter image description here
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How does the tail wake look like when the horizontal stabilizers produce significant lift? Does it merge with the wake from the wing or is there a second wake above the first one?

Edit: I've found this image:

enter image description here
Source

Which shows the tail vortexes below the wing vortexes, and apparently larger than them.

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    $\begingroup$ Oops - what looks like a tail vortex to you looks like the contrails of the inner engines to me. $\endgroup$ – Peter Kämpf Jul 2 '17 at 21:19
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If you look from enough of a distance, the answer is yes.

Close up, both will have their own developing wake. The boundary layer leaving wing and tail will leave a speed discontinuity, and the downward moving wing wake will be complemented by a tail wake which will slow down this downward movement directly behind the tail and increase it left and right of the central tail wake. Normally, the horizontal tails of transport aircraft produce a considerable downforce during landing to compensate for the backward shift of the center of pressure when the high lift devices are employed.

Aircraft model flying through illuminated smokescreen

Aircraft model flying through illuminated smokescreen (picture source)

In the animated GIF above you can see the wake of the tail as a darker box inside the bigger wing wake. It forms two small vortices which rotate against the rotation direction of the wing wake and get spread out when being absorbed by the wing wake.

Friction will soon dissipate the much weaker tail wake, so at some distance all what is left is a single wake which will look slightly distorted around its center when compared to the wake of the isolated wing.

Fun fact: The negative lift on the tail can even contribute some thrust.

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  • $\begingroup$ Awesome GIF, I'm mesmerized; have watched it like 100 times. Can almost see the opposite rotating vortices off of the tail, but its almost instantly destroyed by the churning of the wing-tip vortices and downwash. $\endgroup$ – Devil07 Jul 20 '17 at 14:53
  • $\begingroup$ @Devil07: Hehe, you made the same experience as I did. The tail vortex is hard to see, but is real. $\endgroup$ – Peter Kämpf Jul 20 '17 at 16:01
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    $\begingroup$ If a picture is worth 1000 words, this GIF is worth 10,000 words. ;) $\endgroup$ – Devil07 Jul 20 '17 at 16:11

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