2 ms·

Sounds like Crow Instability that can be seen with large airplanes (https://en.wikipedia.org/wiki/Crow_instability https://en.wikipedia.org/wiki/Crow_instabilit

Sounds like Crow Instability that can be seen with large airplanes (https://en.wikipedia.org/wiki/Crow_instability https://en.wikipedia.org/wiki/Crow_instability) https://epod.usra.edu/blog/2011/08/crow-instability-in-contrails.html%20 https://epod.usra.edu/blog/2011/08/crow-instability-in-contr... https://epod.usra.edu/blog/2015/05/hybrid-contrails-with-crow-instability.html https://epod.usra.edu/blog/2015/05/hybrid-contrails-with-cro...

maxbond 3y ago
[ES: Informed speculation] I think it's a different mechanism, I think it's more like when you squeeze a drop of food coloring into water. I think it's something along the lines of, the friction on the outside of the drop and the momentum of the fluid on the inside of the drop impose a force in opposite directions, causing the fluid to spin, resulting in a vortex; because the cross section is a near perfect circle, this rotation is balanced, and you get a toroidal vortex. I imagine that, the bigger your drop, the more error you can tolerate in your circle. So by the time you get to the scale of, say, a caldera[1], there's a lot of room for error. (That's a slightly different mechanism, but I think comparable in this way.) The photos don't look like what I saw. They weren't oriented like that (they were hanging down like the clumps, perpendicular to the planes direction of motion), and they weren't so well formed. They were more lumpy. But this was a couple years ago and I didn't take a picture, so I can only go off of my recollection, and my strictly intuitive understanding of the fluid dynamics from the thousands of rings I used to blow smoking Black & Mild in my mispent youth. (You can also see rare and interesting rings that way, but I wouldn't recommend it!) Very cool stuff that I'm pumped to know about and will look out for though. Thanks! [1] https://66.media.tumblr.com/e0dd679a1c62751f09e702d8c005b9a1/tumblr_p5vbu5GHSg1sq04bjo1_1280.jpg https://66.media.tumblr.com/e0dd679a1c62751f09e702d8c005b9a1...

maxbond 3y ago

[ES: Informed speculation] I think it's a different mechanism, I think it's more like when you squeeze a drop of food coloring into water. I think it's something along the lines of, the friction on the outside of the drop and the momentum of the fluid on the inside of the drop impose a force in opposite directions, causing the fluid to spin, resulting in a vortex; because the cross section is a near perfect circle, this rotation is balanced, and you get a toroidal vortex. I imagine that, the bigger your drop, the more error you can tolerate in your circle. So by the time you get to the scale of, say, a caldera[1], there's a lot of room for error. (That's a slightly different mechanism, but I think comparable in this way.) The photos don't look like what I saw. They weren't oriented like that (they were hanging down like the clumps, perpendicular to the planes direction of motion), and they weren't so well formed. They were more lumpy. But this was a couple years ago and I didn't take a picture, so I can only go off of my recollection, and my strictly intuitive understanding of the fluid dynamics from the thousands of rings I used to blow smoking Black & Mild in my mispent youth. (You can also see rare and interesting rings that way, but I wouldn't recommend it!) Very cool stuff that I'm pumped to know about and will look out for though. Thanks! [1] https://66.media.tumblr.com/e0dd679a1c62751f09e702d8c005b9a1/tumblr_p5vbu5GHSg1sq04bjo1_1280.jpg https://66.media.tumblr.com/e0dd679a1c62751f09e702d8c005b9a1...