When the wing vortex (technically called the bound vortex) arrives at the wingtip the changed flow conditions cause it to change direction and continue rearwards as a trailing (aka wingtip) vortex. Since for any vortex the velocity increases and the static pressure drops as you move towards the core if the conditions are right any water vapour condenses out and we “see” the vortex as a contrail. These vortices are real!
The only part of that statement that is correct is "these vortices are real"
The illustrations that are provided with the entire post are oversimplified and misapplied to wake turbulence...
This is likely the result of a reliance on CFD models, and other nonsense that has prevailed for many years, but is now thankfully being addressed. These illustrations show a wing section in a wind tunnel, with simulated winds. Smoke or other methods are used to detect the airflow around the wing section, or even a wave tank with colored water.
Notice that the airflow in the section is not deflected? How is lift generated of airflow is not deflected?
Rollup of the vortices occurs at the location of the wing where the laminar flow over the top of the wing disconnects from the top of the wing surface, NOT at the wingtips. (notice on your illustration that the condensation trail originates from the outward edge of the flap)
Here is a better example...757 (note how wing/outboard flap config affects vortex gen? just wait until you see the vortex behind a 787....
The rollup...
What has been oversimplified is the illustrations noted. There is no accounting for the weight and varied surfaces of the aircraft/wing, and in general, the overall issue that air can be compressed, while water cannot.
It is relatively easy to see the illustrations that have used CFD, such as those you have shown, but as we are finding out...cannot explain wake vortex creation.
Just look at winglets touted as reducing wake as a great example.
