Physics of Bubbles Underwater

Hello HiTekRedNek

That 3-1/2 minute video is the MOST interesting thing I have seen in quite a while! I watched it twice before coming back to say NICELY DONE!

http://wimp.com/dolphinbubbles

Let's see if I have better luck with a link.

It occurs to me I did not even attempt to answer you question. I will watch the video 3-4 more times, and perhaps offer an incorrect answer.

Just too cool for words. There is nothing I could say that would do this any Justice.

Very cool! Can I take a stab? I'm a smoker: If I blow smoke out of my mouth, it naturally rises because the smoke is warmer than the surrounding air. However, if I blow a smoke ring, I can actually make it hit the floor. Within the smoke ring the smoke is spinning in on itself allowing it to overcome its natural proclivity to rise, that spinning motion creates a border that's more dense than the surrounding air and allows it to cut through on its own trajectory. I took a shot, who says smoking is bad! Thanks for the post.

Appears similar to vortices off the tips of airplane wings, which move (sometimes sideways, backwards) with the aerodynamics of the surrounding air. In this case, the high surface tension of the air/water interface keeps the vortex in the form of a toroid moving with the local currents.

Having said that, I think it is actually better described by simply saying "Way Cool".

I,too was amazed at the video.But after watching it a few times, I began to think "What th.. is going on here?" How do these bubbles maintain integrity and not rise and disentegrate? I wish there was an accompanying audio of the dolphin sounds while this was going on.I think they may be assisting the cohesiveness of the bubble with their ultrasound.Perhaps a traveling sound wave trapped inside the torroid? The pressure would keep the water and air separated, but as to how they maintain position without rising, beats me.Gyroscopic effect? Are the water molecules actually spinning on the inside surface of the bubbles?

I noticed that when left horizontally oriented, the rings did rise and breakup.I am still scratching my head on this one.And the dolphin broke out a small ring from a larger one?

I posted it here, to get more people interested and hopefully gain some understanding of the physics this amazing feat.

I understand how bubbles go down in certain stout ales, but this is totally different process.

All inquiries and ideas welcome.

I think the air molecules are spinning within the ring. The outside water pressure is actually helping to maintain the integrity of the ring, thus allowing it to be manipulated like that. Back to the smoke ring analogy, if I were to try to manipulate the smoke ring like that it would disintegrate immediately, because the spinning air inside the ring is only slightly more dense than the free floating molecules in the surrounding atmosphere, but dense enough that they can retain their shape and push their way through. The spinning motion of the air inside the ring, under pressure is just enough to keep the water at bay, if the spinning stops, the water takes over and the rings break up into individual bubbles. I'm not absolutely positive, but it seems as if I've seen this phenomenon when looking at footage of torpedoes being fired from submarines from underwater. As to how the dolphins have figured this out and are able to teach this to each other, I'm totally amazed and perplexed. I might just put it on my hard drive though, to watch when I feel the need to relax. If dolphins were able to blow smoke rings on the surface, they would be the size of inner tubes, the compression of the water would also serve to accelerate the spinning as the rings are forced into a smaller space.

I see the dolphins moving their heads in circles around the bubbles. I think they are making both the air and the water spin in a way that the natural rising of the bubble is canceled by descending water.

Sort of like watching the bubbles in a Guiness falling at the side of the glass.

They are moving their heads and creating a vortex at times, but is the vortex the only thing they are doing? Are they beaming ultrasound also, to assist cohesiveness.Sure wish there was underwater sound to go with this video.Perhaps the differential in speed of sound thru air versus water has created an acoustic echo chamber within the bubble.When they eject the bubble,perhaps they also insert sound into it.Notice how when they stretch the bubble, it remains about the same tube diameter? Are they putting in more sound to do this?

From a Google search: Dolphin Blowhole Construction:

Also, and very importantly, the blowhole serves as the opening from which the dolphin's vocalizations are sent. Because the dolphin does not have vocal cords as we do, it produces sounds through the movement of air in its nasal passages located below the blowhole within the upper portion of the melon. It vocalizes by pushing air back and forth between air sacs within these nasal passages. A complex of tissue called "phonic lips" project into the nasal passages. When air reaches these lips they vibrate, creating its sounds of clicks, chirps, whistles, squeaks, moans, grunts, and creaks.

The site: http://understanddolphins.tripod.com/dolphinblowholeandbreathing.html

Maybe a clue here?

Since posting this, in my pursuit of an answer, I have found a Beluga whale that imitated a custodian blowing smoke rings at the aquarium.The whale blew his own bubble ring.Another one blows air-bubble rings at tourists that he sees thru the glass, and can aim the bubble very accurately.They call it blowing kisses.He never misses his target.There is a killer whale that blows a huge inner-tube sized bubble in Japan.

These creatures are amazing.Imagine, if we could learn what they know about ultrasound and hydrodynamics.We might even encounter some unknown physics that they take for granted,or at the very least, some unique applications of known principles.

Keep the ideas coming.

Another amazing detail is the nature of the skin and it's ability to adjust to the fluid dynamics.

Their world is fluid, they must be masters of fluid dynamics.

I would say that it is vortex phenomena. Understanding this would also show us why tornados are stable when they should be torn apart. There are centripetal forces we do not understand fully, that can clearly be circular and not just linear. Compressive flows around the dolphin heads and differential currents are required and are being played with by the dolphins. I suspect that they can actually see or sense these flows or currents in the water or around their heads.

Maybe it's just their way of saying, " hey, dumbasses" we are smarter than you are. We manipulate bubbles, a feat that you will not only, not accomplish, but may not ever understand.

A probably much too simple explanation could be that each tiny bubble within a ring is air encased in heavier-than-water mucus so that it has an almost neutral buoyancy. The behaviour of the whole ring seems vortex-controlled and the dolphins seem to play a game.

It is as kramarat said. They are the water equivalent of smoke rings. There is no air associated with the rings. A smoke ring (I was an addict -about 200/day) can go clear across a room though it is almost all just air. The intense spin gives it a stability. There could be an added aid in the surface tension being modified by the body fluids. Whatever the physics, it is fun! bioramani

I should mention, that, for those non smokers, if you ever find yourself in a very thick fog you can blow inverse rings into the fog, in other words, you can blow clear rings through the fog, it's pretty neat and you don't have to kill yourself to do it.

Now THAT I gotta try... Next winter, if I'm lucky. I'm a non-smoker

This is a pretty interesting concept! Thanks to the OP for posting!

No problem! Lots of tule fog up there. I have a friend that goose hunts up there a lot. If you have a hard time forming rings, blow puffs of air through a paper towel tube, it makes really big lazy rings.......I wonder if I'm part dolphin........

Actually, I'm at a high enough altitude (2100 ft) to be above virtually all the fog ( usually peaks between 1500 & 1800ft), but this is sufficiently interesting, that I think I can remember to make a special effort to go down into the fog next winter.

Thanks again...

If we can understand why these toroids do not break up and float, then we might have an insight into why galaxies do not fly apart without introducing "Dark Matter".

Ball lightning is another mystery of similar intrigue.

If Newton had seen this, he may have modified or expanded his theories or added some new principles.

What we need is another modern day Newton.. (I know, I know, we have FIg Newtons, but that is not the same)

The main forces at work here seem to be surface tension,air pressure( to form a bubble, it had to have a greater pressure than the surrounding water when expelled from the blowhole.)The temperature of the air, which is greater than the water temp,perhaps forming a barrier at the surface interfaces.

The cooling of the air in contact with the surrounding water, the possible input of sonic energy by the dolphin.The air is also heavily laden with moisture from the lungs of the dolphin.The centrifugal force, which works against all of the other possible cohesive forces,and specific gravity,which seems to be temporarily neutralized by this interaction.Perhaps the molecules are traveling in a spiral inside the torroid, creating yet another layer of complexity.Perhaps they are kept in motion by periodic bursts of sonar from the dolphins.Perhaps when forming the bubble, the dolphins create a cavitation path for the air to follow.They may be tilting their head for more than one reason.

The answer is beyond my present ability to analyse, but I will consult with my braintrust and if they are willing, I will gain some insight into the mystery.

As always, my ears and mind remain open for all ideas and suggestions.

Just wish I was 16 again, I had all the answers then.Now I am too old to know it all.

Quote:[The main forces at work here seem to be surface tension,air pressure( to form a bubble, it had to have a greater pressure than the surrounding water when expelled from the blowhole.] Unquote There is no air at all. It is a water vortex similar to smoke ring in air. One sees it because of the refraction at the vortex and the stationary water interface aided by any modification of the film water by the dolphins body fluids. As can be seen in the video when the ring disintegrates there are no air bubbles dispersing into the surrounding water. bioramani

Ok, if we go that route, what prevents the cavitation bubble from collapsing in upon itself?

How does the dolphin create such a magnificent torroid with cavitaion?.I do not see any cavitaion forming at the dolphin's nose, only a path for the bubbles to follow.

The governrment would certainly like to know how to mimic this cavitation priciple, if in fact it is cavitation.If so, it is way ahead of the present technology of cavitating torpedoes and projectiles.Perhaps a government study is in order.

Cavitation is used to destroy ships, by exploding a torpedo below the hull, creating a giant cavitation bubble, that literally lifts the ship out of the water,which is followed by the explosive force itself, a double whammy.Then there are the cavitating torpedoes that exceed the speed of sound in water by generating a cavitation bubble around the torpedo.These torpedoes are faster than sonar, so they are stealthy, except for the last few yards, where they brake to normal speed before exploding.

If we could generate and control it like these dolphins,we could create a bubble-ring curtain around ships in port, to keep other vessels ( and torpedoes) outside of the perimeter.A cavitating torpedo that loses cavitation will self destruct.

Imagine a rod or tube immersed in the water, generating large standing bubble rings around it, using sonar to maintain spacing and integrity.Now imagine a "fence" made of these.

I know,, fantasy or sci-fi right? Some of my ideas are just born prematurely, I guess.

However, I see bubbles leaving the dolhins' blowhole,and bubbles when they break up.I have played it in frame by frame mode.Perhaps these old eyes are deceiving me.

The bubbles, however, are very small, being compressed at last by the water pressure.So what force is resisting the water pressure?

Or at least, that's the way I see it.

I apologize if I was unclear. I am saying that as smoke rings are essentially air rings in air and have an identity only because of the vortex, likewise the dolphin rings are water rings in water. There is no cavitation and no great pressure difference. Such a ring can be blown just like blowing smoke rings in air. IF there is a cavity like the inside of the mouth full of water and a sudden smaller diameter jet of water is pushed like from a constricted throat, this jet sets up an intense swirling motion of a ring of the fluid in the stationary zone at the exit. The lips and teeth aid this. Once the high speed small diameter jet crosses the lips the swirling ring nearly a perfect circle gets released and slowly moves away. The viscous drag in water being much more than in air such a ring may not have such a long life as smoke rings. You can easily make water drops float on water if there is a minuscule contamination of the drop to alter surface tension slightly. Since such a vortex ring is stable (at least for a while) it has an interface and whenever there is an interface one can have optical phenomena like total internal reflection and such. An oil film a few angstroms thick produces diffraction rainbow colours in puddles. You are right in that there is no cavitation and that conditions at the dolphin's nose is far from cavitation. The dolphin is doing nothing more exciting than a smoker blowing smoke rings with as little effort. However, it is lot more fun to watch. You can see the dolphin maneuvering the rings by giving a long wavelength swirl with the nose from a distance away after the ring exits. An amazing show! Bioramani

Why are these vortices so clearly visible? Smoke is used as a marker for air in air vortex rings, what is the marker for water in water vortex rings?

Are we watching the same video? The blow hole is the dolphins breathing apparatus. If it were blowing out pure water, that would indicate that its lungs were full of water and it would be dead.

Hi,

without any doubt these are vortex-rings.

These can be made with smoke in air but that is in reality air in air and the smoke is only for visibility.

With air in water the water has the swirling motion else there would be no vortex of useful energy.

Any cylindrical vortex is stable in itself and giving a force depending on the movement of the surrounding fluid. This force relocating the vortex. This is the situation in Tornados.

The ends of the vortex have to be attached somewhere to stay stable. So if the vortex (thin and long) is bent to a circle there are no more any ends. This is a very stable situation.

These dolphins are really scientifically interested artistic players - only we humans should try to decode (and transform in frequency) their language!

RHABE

On several of the formation maneuvers, ie, at 50 seconds and 57 seconds you can see they first create a vortex in front of themselves by pulling their heads in a swift downward stroke, and then they lift their heads back into the vortex they just created, and blow their bubble jet into that vortex, which vortex tube pulls the bubbles into the ring shape.

At other times, the more experienced ones seem to use natural or passing vortices, perhaps those created by other, passing dolphins, and they blow into those to create their rings.

I guess being locked up like that they got to amuse themselves in some way.

If you've ever been on a yacht in dolphin waters you'll know just how naturally playful these lovely creatures are.

I noticed a degree of "cloudiness?" or opacity when the rings collapsed.

Could ultrasonics be a factor in the formation of these rings?

Here is a preliminary analysis... to check my assumptions.

• Both the dolphin and the ring are moving forward.
• Relative to the dolphin/ring system, the water may be static. (no further external currents required to produce rings)
• Water must flow around the dolphins head shape.
• Water is generally incompressible.
• An increase in fluid pressure is created when dolphin is moving forward around the head.
• At certain points, the pressure increase is a steep slope. (call it a shock wave)
• The bubbles may be 'surfing' the shockwave in this zone. (toroidal zone around nose)
• I think the rings would be rotating counterclockwise.
• Internal ring air pressure is further opposed by centripetal vortex pressure, and 'ring tension'.
• Bubble pressure is less than atmospheric pressure, so buoyancy is decreased until all other forces stop acting.
  Centrifugal forces in ring are larger on the upper side due to both buoyant force, and steeper shock wave.
• Ultrasonics, water-jets (spitting) and other forces are not required, as evidenced by the fact that the ring exists regardless of mouth open, or head angle. It is stable in the water until the relative flow stops.
• these sorts of rings can also be observed (created) in the tub drain. (try injecting air with syringe)
  

okay... I just watched the video again.. sometimes the rings are a few feet ahead of them.. so the don't have to be in the zone to stay spinning... so I'm wrong about part of these assumptions anyway.. ... so some questions then, for those of you who are doing frame-by-frame...

What direction do the bubbles spin?
Do the dolphins slow down from an initial speed?

Chris
(confused as ever)

As the last guest wrote, the rings seems to start by being lines that are later closed to form rings. And, to repeat, why are the lines and rings visible? What plays the role of smoke that makes smoke rings visible?

What? This conversation, just like the rings themselves, eventually begins to degrade and become unstable. The reason smoke is visible, to answer your question, is because it is made up of tiny particles of carbon, along with all of the other noxious chemicals that are associated with the burning of tobacco.

A whole lot of dolphin and a few non dolphin water vortices: http://www.google.co.in/search?q=water+vortex+rings&hl=en&prmd=v&source=univ&tbs=vid:1&tbo=u&ei=SV8vTNbzB4OFrAedi6X0BQ&sa=X&oi=video_result_group&ct=title&resnum=4&ved=0CD4QqwQwAw bioramani

Thanks to bioramani for the pointer to Google's almost infinite fount of knowledge. It looks as if humans can do it too, but their rings are definitely air-in-water and they definitely rise and break up into fairly large bubbles. Dolphins make thinner rings which do not rise and when they break up - the resulting bubbles are much smaller. Vortex technology - certainly, but I guess dolphins add some surface active stuff.

The ink drop video is water drop in water. The entire episode is under water. bioramani

Google shows several movies of different human beings (male) either standing on their heads on the bottom of a swimming pool or lying on their backs on the floor of a swimming pool (or reservoir). They use their mouths and (presumably) their air-filled lungs to blow beatiful air rings which buoyantly rise and keep their shape until they break up into bubbles.

It seems the dolphins know a lot about underwater physics

Have any of you actually tried to manipulate bubbles in water?

I just spent an hour in a swimming pool last night with scuba gear.

I think that the right person, with enough time, (and a bigger pool) could probably manage to do this.

The biggest problem I have, seems to be with keeping up with the bubbles as I push them through the water.

That and the nearest place I can get my tanks filled is 2 hours away.

( I have GOT to quit smoking)

http://www.youtube.com/watch?v=WS-XiwcNVqQ

This is as close as I can come to a solution, if that means any thing. I'm a bit in a rush to explain why this happens but it could be based on the same principles. There could be a "protective layer" separating the breathed out "air" from the water. It could be steam, like in the case shown in the video above or it could be the CO in the breath that creates something like a buffer zone.

I could hardly sleep after I saw it but we will find a solution. We were Dolphins once so whats the problem?

Also my question What Happens to the Balloon? ,a while back, makes me well prepared to tackle this one, I hope.

HiTekRedNek

Thanks for supplying us with this fantastic footage. Amazing that it hasn't hit you tube big time yet.

Just a few sleeps and we will know, Ky.

http://www.youtube.com/watch?v=bgC-ocnTTto&feature=related

For a short time it looks like a ring. I'm hooked now.

There is a flick of the tail and stalling of the pectorals, causing a flow over body in a reverse direction, which carries the air forward for manipulation by mouth and nose movement generated turbulence.

To me it is more like the smoke ring analogy than anything else.

It certainly is a skill and fun to see - but not "magic" or an 'unknown Law' or "ultrasonics" or mucus or .....

More interesting that they are learning it and 'competing' for best and trickiest.

Better than boredom sending them insane.

Kyzine

It looks to me as if the dolphins move the bubbles around with their snouts - by pushing the water near the bubbles. This is certainly the case when the bubble is moved around its axis. When left to itself a bubble does rise through the water.

To All,

While pondering the principle of the rings at my local aquarium, I realized my wallet had been replaced by a mackerel.

There was a trail of water leading back to the tank. One of the gang members emitted a bubble cluster in the shape of an "L".

Makes sense GA

I think they squirt out the air bubbles first and then squirt the jet of water below the bubbles at just the right distance. Doesn't need to be a big long jet of water, just lots of power in the jet. Maybe a sudden rush and then full stop. (They do not have to inhale the water) the muscles at the top of the blowhole might be enough to make it happen. The vertex forms from the water jet and then traps the bubbles in the vertex. So it is just like a smoke ring.

It is certainly a beautiful thing and it might have applications. Sending air into fishponds, or into activated sewage, perhaps. Or the chemical industry. Maybe we will see underwater "fireworks" and smoke breathers? Can anyone do smoke rings with mouthfulls of coloured water in their pool?

Edited to add. (Sorry, I refreshed and it looks like other have already come to similar conclusions).

O.K. This may be a good case for Occam's Razor.

Dissecting the "physics" of it may lie in analyzing the shape of the dolphins blow-hole.

... and how they manipulate it's shape... sort of like our larynx.