Engineers explain physics of fluids some 100 years after original discovery

Mar 22, 2013
This figure shows two fluid jets merging into one on the right when just a 20 percent speed increase is applied. Credit: Virginia Tech

Sunghwan Jung is a fan of the 19th Century born John William Strutt, 3rd, also known as Lord Baron Rayleigh. An English physicist, Rayleigh, along with William Ramsay, discovered the gas argon, an achievement for which he earned the Nobel Prize for Physics in 1904.

But it was Rayleigh's lesser-known discovery of a in 1878 that was more intriguing to Jung. Some 135 years ago, Rayleigh wrote that two fluid jets or drops do not always merge into one body of liquid, a counter-intuitive topic or phenomena in physics that has since been studied in much detail, cited Jung, Virginia Tech assistant professor of engineering science and mechanics.

The significance today of this fact is that when noncoalescence takes place between two fluids, it might impact a variety of industrial and everyday processes such as fuel efficiency, ink jet printing, and the development of spray coatings.

New information on Rayleigh's of the collision of fluids now appears in a contemporary paper authored by Jung and Pavlos Vlachos, professor of mechanical engineering at Virginia Tech, and Navish Wadhwa, of Blacksburg, Va., a doctoral candidate in engineering science and mechanics. The paper, accepted in Physical Review Letters, a peer-reviewed journal of the American Physical Society, is called "Noncoalescence in the oblique collision of fluid jets."

"In Rayleigh's original paper, he mentioned two things: drop bouncing on a liquid bath and jets bouncing. No pictures were given. Much work has been done in drop-bath bouncing, but no work has been done in bouncing jets except for a couple of demonstrations in textbooks. We are the first ones to rationalize the physical mechanism of bouncing jets," Jung explained.

In their experiments, the researchers studied two silicone oil jets bouncing off each other upon collision. Silicone oil is used in most experiments in order to avoid any surface contamination, Jung said, and it is often the base for hydraulic fluids or lubricants.

"Intuition tells us that two or more jets of the same fluid impinging into each other will readily coalesce to form a single mass of fluid, and are well-studied phenomena," Jung explained.

Velocity is key to bringing the two silicone oil jets into a single flow of liquid. Since these jets of fluid drag along air, considered to act as a cushion, the two jets will bounce off of each other. But when the speed of the flow is increased beyond a certain threshold, the air is no longer stable due to the high inertia of jets, and the liquid jets will coalescence, Jung added.

To attain in space rockets, two different fuel fluids need to mix well to maximize the combustion.

"In our experiments, we showed they are able to bounce off each other and inhibit the mixing. However, in rocket fuel tanks, the fluids come out of the nozzles are a very high speed, so no bouncing happens in their cases," Jung said.

Jung's earlier work on fluid flow won him the 2010 international Milton Van Dyke award at the 63rd annual meeting of the American Physical Society.

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Q-Star
2.3 / 5 (3) Mar 22, 2013
It's an interesting article. Sounds like good science. Rayleigh is one of my favorite physicists. But,,,,,,,

Why is this posted with the Astronomy articles?
Q-Star
1.8 / 5 (5) Mar 22, 2013
It's an interesting article. Sounds like good science. Rayleigh is one of my favorite physicists. But,,,,,,,

Why is this posted with the Astronomy articles?


To all ya general physics people, we'd borrowed this very interesting article over in the astronomy people's page. Thanks for the loan, ya can have it back now.
Sanescience
5 / 5 (1) Mar 22, 2013
I have always wondered if vibration harmonics can play a roll in liquid convergence/divergence. If the wave form propagation of the impact evenly divides into the width of the liquid volume at a crest or valley. Perhaps testable by introducing vibrations into the streams before they collide. Anyone have any idea?
Q-Star
1 / 5 (2) Mar 22, 2013
Anyone have any idea?


Not a clue, but it sounds like a fun experiment.
ValeriaT
1 / 5 (5) Mar 22, 2013
It's just "open-space" version of Kaye's effect. The coalescing of fluid surfaces requires some time due their surface tension. When this time is not supplied (for example during the surface vibrations), then the water droplet will bounce on the surface infinitely. AWT explains with this analogy the stability of particles of matter in the vacuum.
ValeriaT
1 / 5 (3) Mar 22, 2013
Under certain circumstances the jet can bounce multiple-times... The Kaye effect needs a non-Newtonian liquid for its mechanism to work, as the lubrication layer is a thin layer of shear-thinned liquid. The bouncing jet in this video doesn't. It works with a Newtonian liquid, as the lubrication layer is air.
Q-Star
3.3 / 5 (7) Mar 22, 2013
AWT explains with this analogy the stability of particles of matter in the vacuum.


Zephyr, I'll give ya credit for finding some way to bring "AWT" into any, I do mean, ANY topic. Ya even haunt the biology pages with it.

As far as
AWT explains with this analogy the stability of particles of matter in the vacuum.
,,, goes.

This not an article dealing with anything in a vacuum.

Not an article dealing with anything in the aether.

Not an article dealing with the behavior of particles.

But other than that, ya are right, it is an article about the flow of fluids, in the air, and unencumbered by extraneous ducks. That part ya got spot on.

ValeriaT
1 / 5 (6) Mar 22, 2013
IMO it's important insight, instead. For example, during fusion the droplets of nucleons are coalescing mutually under release of giant amount of energy. The only reason, why it doesn't happen immediately is the surface tension of extremely high density gradient at their surface and the quantum noise, which prohibits their spontaneous merging. Without it all matter would collapse into iron filled singularity immediately (the iron nuclei are most stable in this extent). Another point is, we can consider the coalesce as a macroscopic example of quantum tunneling. A pair of mercury droplets will coalesce after while. What drives this mechanism? A tunneling of mercury across surface barrier, which is required for temporal formation of thin neck of negative surface curvature. Such a coalesce could be accelerated with scalar waves, which do behave like bubbles of vacuum and they would promote the formation of this neck. From similar reason the do neutrinos accelerate the radioactive decay.
ValeriaT
1 / 5 (6) Mar 22, 2013
Another example of surface tension (actually hyperdimensional quantum effects) is the kick of black holes during their mutual collisions. The coalescing black holes are behaving in similar way, like the mercury droplets, which defy their merging. The general relativity predicts the straightforward merging of black holes without repulsive impulse. The huge fibers of dark matter are behaving like the Nonewtonian fluid and they coalesce into galaxies in similar way, like the fibers of slime (Gregory/LaFlamme instability). It's difficult to imagine the mechanism of such behavior without dense aether model. Its point is, at extreme scales the universe behaves as classically, as the universe at the human scale and the effects of general relativity and quantum mechanics do compensate mutually there in similar way, like in the common life.
ValeriaT
1 / 5 (5) Mar 22, 2013
I have always wondered if vibration harmonics can play a role in liquid convergence/divergence.
They would probably slow down their merging up to certain level. At the higher velocity the braiding patterns along streams will be formed and their merging will be accelerated instead. The threshold velocity will be probably defined with speed of capillary waves along water surface, which are driven with ratio of surface tension and density of water.
Whydening Gyre
1 / 5 (4) Mar 23, 2013
So... Valeria/et al has found a medium (aether, if you will) that helps him describe the all the visible pattern similarities we observe in our "present existence". Considering his POV,I can understand his zeal in presenting (what seems to be) an obvious conclusion. In a way, "spacetime" (einstein named it correctly) can be considered the vessel in which all other things "flow" harmonically(for the most part).
I see that that the majority of you have accepted him as an irritating "fact of life". And what's less obvious is that he makes all of you (at some point or on some facts) reconsider your (me included) positions of understanding. I say - Thanks, Val for being the one who accepts that collaborative part in the "play" dynamic. Makes this whole site a lot more interesting.
ValeriaT
1 / 5 (4) Mar 23, 2013
Valeria/et al has found a medium (aether, if you will)
The concept of material environment for light spreading (and scattering) had its historical name - I didn't invented it. I'm using this somewhat archaic denomination with respect to scientific priority of this concept, simply because this name exists already for many years and because the dense aether model was proposed with Oliver Lodge before one hundred years...

The acceptation of dense aether model is similar conceptual shift, like the acceptation of heliocentric model instead of geocentric one. Suddenly we are observing (and describing) the same situation from outside, i.e. from extrinsic perspective instead of existing intrinsic one.

The adoption of extrinsic perspective requires us to adopt the logics, which cannot be fully proved experimentally (after all, nobody of us did ever see the solar system from outside), but which enables us to reconcile the existing knowledge into new more general scheme of thinking.
Torbjorn_Larsson_OM
5 / 5 (4) Mar 23, 2013
Crackpots and their sockpuppets.

- There is no "aether" says observations since over a century, and that is why such comments doesn't fit on science sites.

- Pattern matching is precisely the standard crackpot basis, and is not making anyone 'reconsider' anything. On the contrary, it is confusing, as we can see on crackpot behavior.
Whydening Gyre
1 / 5 (5) Mar 24, 2013
Crackpots and their sockpuppets.

- There is no "aether" says observations since over a century, and that is why such comments doesn't fit on science sites.

- Pattern matching is precisely the standard crackpot basis, and is not making anyone 'reconsider' anything. On the contrary, it is confusing, as we can see on crackpot behavior.

Nikola Tesla's research and discoveries were considered "crackpottery" in his time...
ValeriaT
1 / 5 (4) Mar 24, 2013
Nikola Tesla's research and discoveries were considered "crackpottery" in his time..
And they still are. Nobody of mainstream physicists believes in his scalar waves, for example. Whereas the existence of scalar waves belongs into integral parts of dense aether model.
there is no "aether" says observations since over a century, and that is why such comments doesn't fit on science sites
I know perfectly, what these observations say. These observations disproved the model of thin sparse aether pervading and FILLING the space - not the dense luminiferous aether FORMING space. The behavior of dense aether model is dual to thin aether model in many aspects: for example the sparse aether exhibits drag at low energies already, whereas the dense aether doesn't exhibit the drag even at the large energy density, so it can provide the null result of Michelson-Morley experiment. You never understood this difference, so you have nothing to say about it
ValeriaT
1 / 5 (4) Mar 24, 2013
The hyperdimensional behaviour of fluids can be observed even here, in human society. The ideas and theories are pervading the human society like the foamy density fluctuations of vacuum and/or fibers of dark matter. They're serving for deterministic reproducible spreading of information there. But the different theories are mutually intolerant and they tend to bounce mutually. Their proponents are hostile against each other the more, the more these theories are dense, i.e. the more human energy and money exist behind them. I.e. they exhibit sorta surface tension. The merging of reluctant theories and acceptation of new theory happens only when their density gradients are diminished, i.e. when the understanding of opponent theory reaches some level. For example, nobody bothers with of neptunism and plutonism controversy today, as we already know, both approaches are correct in certain extent.
Noumenon
3 / 5 (11) Mar 24, 2013
Zephyr, I'll give ya credit for finding some way to bring "AWT" into any, I do mean, ANY topic.


Before many years already, by AWT you can fix your car, or get out of a jam after a night of drinking, as like foamy density tension at the water surface,...
johanfprins
2.3 / 5 (6) Mar 25, 2013
Nikola Tesla's research and discoveries were considered "crackpottery" in his time...


The difference between Nikola Tesla and ValeriaT is that Tesla did actual experiments and made measurements so that he was able to quantify his "crackpot" ideas. ValeriaT only hallucinates! No measurements no numbers: Nothing that can be tested by experiment.
johanfprins
3.7 / 5 (6) Mar 25, 2013
The mainstream physicists still don't understand, why something like the scalar waves should exist, why they should be superluminal and how they will manifest itself - whereas the water surface model is quite clear about it. It's all about motivation.


Then use your "water surface model" to derive the correct equations and apply them to some real data! Your hand-waving arguments are not convincing at all.

The evidence for scalar waves comes from mainstream physics theory too. In linearized, Einstein–Maxwell theory on flat spacetime, an oscillating electric dipole is the source of a spin-2 field.


Well, what is your problem? Where is the beef? Write down your "water equations" and your "linearized Einstein-Maxwell equations" and prove that they are the same.

If you cannot do this you are just babbling nonsense as you have now done for many many years on this forum.