foghorn
Valued Senior Member
America may have an eclipse but Europe has its smoke rings.

Video clip at:
https://www.bbc.co.uk/news/av/world-europe-68752290

Video clip at:
https://www.bbc.co.uk/news/av/world-europe-68752290
Curious. I've found an explanation for this here:
QUOTE
Such gas rings are produced by the explosion of gas bubbles within a narrow conduit [above a magma chamber], which shoots the gas at high speed toward the surface," Behncke wrote on Twitter. "Attrition along the conduit walls slows the movement of the gas jet, relative to the center of the conduit," which is what forms the ring shape, he added.
UNQUOTE
From: https://www.livescience.com/planet-...-out-of-europes-most-active-volcano-heres-why
So you get a fast gas jet through the centre but a much slower gas stream at the edge, leading to a toroidal vortex. Presumably you need fairly sticky magma for this, to get the bubbles to explode rather than simply burst.
I seem to recall an uncle who could sometimes achieve the same thing with his mouth while smoking, back in the 60s when smoking indoors in the presence of small children was not yet frowned upon.
That makes sense. You want a sudden, semi-explosive burst of air in the centre and a slow-moving part at the sides, it seems.You can blow smoke rings by a sort of glottal exhalation or just by tapping the cheek.(smaller ones ,from memory)
So, by contact with the walls of the vent the gas bubble’s outer edges are slowed, leaving the centre gas moving faster. When the surface is reached the gases condense to steam.Curious. I've found an explanation for this here:
QUOTE
Such gas rings are produced by the explosion of gas bubbles within a narrow conduit [above a magma chamber], which shoots the gas at high speed toward the surface," Behncke wrote on Twitter. "Attrition along the conduit walls slows the movement of the gas jet, relative to the center of the conduit," which is what forms the ring shape, he added.
UNQUOTE
From: https://www.livescience.com/planet-...-out-of-europes-most-active-volcano-heres-why
So you get a fast gas jet through the centre but a much slower gas stream at the edge, leading to a toroidal vortex. Presumably you need fairly sticky magma for this, to get the bubbles to explode rather than simply burst.
Good point. If it is condensed water droplets that form the ring, I suppose it could be lower temperature in the gas at the edge…..So, by contact with the walls of the vent the gas bubble’s outer edges are slowed, leaving the centre gas moving faster. When the surface is reached the gases condense to steam.
But, why does the centre gas not condense also?
Is it that all the gas is worked (by friction) to the sides and so a ring appears? I don’t know if I’m making sense even to myself?
I can see why it has to be a 'packet' of gas rather than a continuous flow of gas, otherwise that would be a column of steam.
Btw. I can’t find any accounts of what people made of these rings in the olden days.
But then that would not explain smoke rings from a cigarette. I suspect in that case one has a mouthful of smoke through which a burst of relatively smoke-free air from the throat is expelled. So perhaps in the volcano there is a cloud of condensed vapour hanging about in the mouth of the vent and then a sudden burst of hot gas from below passes up the vent, causing the condensed vapours to roll out in the form of a ring. But I am speculating.
Looks awesome.America may have an eclipse but Europe has its smoke rings.
View attachment 5855
Video clip at:
https://www.bbc.co.uk/news/av/world-europe-68752290
That's interesting. What does one do with one's tongue, then, to generate a smoke ring?The tongue plays a big part of creating smoke rings, I can do them. Your jaws also. My cousin is amazing at doing them, his jaw movement seems to play a better role then mine do. Better smoke ring jaw movement I guess.
I sort of fold it up, as to create the emptiness in the middle of the ring. There may be different ways to achieve the ring but I would think curling your tongue would be universal. I'll ask my cousin next time I see him.That's interesting. What does one do with one's tongue, then, to generate a smoke ring?