2
$\begingroup$

If you have 2 vortices rotating the same direction, how will they interact with each other? For example, if you have 2 tip vortex sized vortices close to each other and rotating the same direction, how will they combine? Will they have any sort of 'suction' or attracting force towards each other? If so, why is that?

(I would ask what would happen if they were counter-rotating, but this question already has answers)

Say you have 2 wheels that are spinning in the same direction. if you try to put them together like gears, they will try to cancel each other out, or try to spin the other one the opposite direction. That's why I'm confused as to how vortices combine.

Thanks, and happy new years!

$\endgroup$
1
  • $\begingroup$ Intuition is tricky because vortex merging depends on many things. Be perplexed by these two paper abstracts, for example. $\endgroup$ Dec 31, 2023 at 20:28

1 Answer 1

1
$\begingroup$

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 the other. If you have two vortices rotating the same direction next to each other, they will combine into a single, stronger vortex.

$\endgroup$
6
  • $\begingroup$ oh okay, thanks. So is my analogy of the 2 wheels spinning in the same direction incorrect? It seems like the same principle, so it's confusing as to why they add to make a bigger vortex. $\endgroup$
    – Wyatt
    Dec 31, 2023 at 19:16
  • 1
    $\begingroup$ The analogy is correct. Where two clockwise wheels meet, they cancel out "inside" of the bigger combined vortex. But their outsides survive, like a chain or belt around them both. $\endgroup$ Dec 31, 2023 at 20:25
  • $\begingroup$ @CamilleGoudeseune ah okay, thanks. Yeah I kind of thought something like that would happen. One last question, do 2 vortices next to each other have any attracting force? $\endgroup$
    – Wyatt
    Dec 31, 2023 at 21:19
  • 1
    $\begingroup$ @Wyatt as the answer says, the vortices will combine so you could say that they attract each other, but remember that a vortex isn’t a ‘thing’ in its own right, it’s differential movement of air. $\endgroup$
    – Frog
    Jan 2 at 2:38
  • 1
    $\begingroup$ @Wyatt No, the resultig vortex is the sum of both. When the adjacent halves cancel each other, what remains are two outer halves at a wider distance. Since vortex velocity is higest at the center and drops inversely with distance from the center, the two halves at a wider distance combine into a stronger vortex. $\endgroup$ Jan 31 at 22:29

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .