Source of the first photo

I saw this photo of business jet touching down (first picture) and the smoke of tires forming wake turbulence . as I have provided other pictures (second and third) of "what we have seen and know about the theory of wake turbulence" , you can see this strange upside down form of wake turbulence . simply what is the reason ?

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    $\begingroup$ Unless you made these great pictures yourself, please provide attribution. $\endgroup$ – Sanchises Sep 1 '17 at 14:19
  • $\begingroup$ sorry couldn't work with tags and brackets , "stackexchange" can provide and easier uploading mechanism though . $\endgroup$ – HOMAYOON Sep 1 '17 at 14:38
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    $\begingroup$ No it was fine the way it was (images visible), but just provide a link to where you got the pictures in the first place, in the text below. And agreed, it's sometimes a bit confusing. $\endgroup$ – Sanchises Sep 1 '17 at 14:46
  • $\begingroup$ oh I'm so sorry , misunderstood . here is the link sir : mg-aviationphotography.com/uploads/9/8/4/5/9845374/… $\endgroup$ – HOMAYOON Sep 1 '17 at 14:51
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    $\begingroup$ we would need the source also of the other 2 photos. thanks :) $\endgroup$ – Federico Sep 1 '17 at 14:57

Actually, yes, it is "upside down" as compared to the respective wing-tip vortices.

Your picture shows the vortices coming off of the horizontal stabilizer, enter image description here

which rotate in the opposite direction of the wing tip vortices that come off of the wing tips. Notice in your original pictures, the 2nd and 3rd pictures show the wing-tip vortices off of the airplanes right wing (as viewed from the front) rotate counter-clockwise. However, in the top picture the right vortex rotates clockwise.

That is because the horizontal stabilizer (along with the elevator in the UP position) is basically acting like an upside down wing defecting air upwards (as the picture illustrates). The high pressure region on the horizontal stabilizer on landing is on the top, while the high pressure region on the wing is on the bottom. This accounts for the opposite direction of rotating between wing tip vortices vs horizontal stabilizer vortices. The upwardly deflected elevator deflects the relative wind upward at the tail causing that upward movement of the rubber smoke.The picture is cropped so we can't see the wing-tip vortices (assuming there was dust or smoke in the air to view them).

Peter Kämpf posted an amazing GIF here showing a slow motion flight of a model 747 going through smoke that shows this process. Its difficult to see, but for a brief moment after the aircraft passes through the smoke, you see the hint of the horizontal tail vortices trying to rotate and go up, but they are washed out by the enormous downwash of the wings.

  • $\begingroup$ @ymb1 Thank you! That is the correct gif! If you watch it carefully (an repeatedly) you will see faint opposite vortices coming off of the horizontal stabilizer, but they are overwhelmed by the massive downwash of the main wings. Its pretty amazing. $\endgroup$ – Devil07 Sep 3 '17 at 1:40

enter image description here

This is not wake turbulence. This is a hard landing. The smoke from the tires is hot, it rises, hits the fuselage, curls away from it, and then curls back on itself due to the Rayleigh–Taylor instability.

enter image description here
(YouTube) A more persistent example. Note the still rising column of smoke.

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    $\begingroup$ I think convective effects are vanishingly small compared to turbulence around a 747 at speed... $\endgroup$ – BobT Sep 1 '17 at 16:34

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