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Recipe for Making Symetrical Holes in Water
scottZed writes "Danish researchers found a simple way to make curiously shaped air holes in a bucket of water. Simply rig the bucket to have a spinning plate at the bottom, and depending on the speed, you can get an ellipse, three-sided star, square, pentagon, or hexagon. The effect may help explain such shapes seen in atmospheric disturbances on Earth and other planets. One practical use: really trippy washing machines."
This from a publication with the byline "the best in science journalism"
Bah!
I know those monkeys are at it again..
Aliens obviously use the plate to transmit geometrical patterns in an effort to contact us. This proves it beyond all doubt.
Coral Cache FTW
But... how will this increase computing speed? Surely some scientist can make something up. Think of the children growing up right now with 3.2ghz dual cores!
This looks like something out of a sci-fi show :D
But seriously, what if in the ocean the waterflow is spinning very hard itself under certain conditions, wouldn't that be a possible explanation for the disappearances in the Bermuda Triangle?
This is the sig that says NI (again)
I'm curious about the researcher's name, Tomas Bohr, any relation to Niels?
Of course, it might be explained ... in the future.
It looks like the end result of system resonance set up between the harmonics and the properties of water. It would be cool to artificially vary the viscosity of the water with polymers, or add salts to increase specific gravity to note the affect on the pattern properties. OK, some of you are thinking, this guy is a nut but it just proves how never ending the learning process is as it relates to even the simplest things observed in nature. I like it.
I say "Triangle"
Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
One practical use: really trippy washing machines
practical
adj 1: concerned with actual use or practice; 2: guided by practical experience and observation rather than theory; 3: being actually such in almost every respect; 4: having or put to a practical purpose or use;
This is real advance in physics!
Maybe Computers will never be as intelligent as Humans.
For sure they won't ever become so stupid. [VR-1988]
With geometrically shaped vortices could be used to put out odd shaped fires? no?
One, it's not a recipe. Two, the holes are not symetrical. At least you got the water part correct.
pedantic
adj 1: Like a pedant, overly concerned with formal rules and trivial points of learning; 2: Being showy of one's knowledge, often in a boring manner; 3: Often used to describe a person who emphasizes their knowledge through the use of vocabulary; 4: Being finicky or picky with language.
A cake with a geometric-shaped bubble in the middle with cream filling. Either Rachael Ray will be all over this, or it will be quick fire challenge on next season's Top Chef. The possibilities are endless.
SymMetrical.
Anyway, this isn't exactly a groundbreaking discovery.
One practical use: really trippy washing machine
Yes, but only if you run it without any clothes. Very practical indeed!
"You mortals are so obtuse." -Q
This is a simulation, not a competition.
These are scientists at work, they've been doing science stuff for years.
its about time!
The article says "At high enough rotation speeds, he says, a fluid will always experience some flow instability that creates a symmetrical structure."
But doesn't the resulting symmetry show that what is achieved is a degree of stability? I've always thought it odd that in so called "chaos" theory, "chaos" is said to result in patterns (fractals) -- but doesn't the fact of a pattern belie "chaos"?
DAILY ROTATION
When the dutch scientists spun the bucket ever faster, the shapes became even more interesting. It's a pity they were left out of the article. View them here:
http://www.craigslist.org/sby/tls/163096693.html
~those crazy dutch scientists! what will the think of next!
Hey, I know these guys! Way to go!
/.) OTOH, having an advisor from the Bohr family probably doesn't hurt.
This just confirms my suspicion that the chance of a Nature publication is directly proportional to alcohol consumption. (Wonder what it takes to get on
The academic lowdown:
ArXiv preprint
The full B. Sc. project
Now, if only we could make 60gons...
Any sufficiently advanced libertarian utopia is indistinguishable from government.
"We report a novel and spectacular instability of a fluid surface in a rotating system. In a flow driven by rotating the bottom plate of a partially filled, stationary cylindrical container, the shape of the free surface can spontaneously break the axial symmetry and assume the form of a polygon rotating rigidly with a speed different from that of the plate. With water, we have observed polygons with up to 6 corners. It has been known for many years that such flows are prone to symmetry breaking, but apparently the polygonal surface shapes have never been observed. The creation of rotating internal waves in a similar setup was observed for much lower rotation rates, where the free surface remains essentially flat [J. M. Lopez et al., J. Fluid Mech. 502, 99 (2004).]. We speculate that the instability is caused by the strong azimuthal shear due to the stationary walls and that it is triggered by minute wobbling of the rotating plate."
What do you mean, "any more" ?
Forget magic. Any technology distinguishable from divine power is insufficiently advanced.
mmm ... tasty eigenmodes abounding. Congratulations. We study this kind of crap all the time in the Applied Mathematics program at Univ. of Washington. Can't imagine it's so different for other programs.
That being said, I like the nice pictures. I've seen some interesting pictures where a thin layer of fluid is trapped between two cyliders. The inside cylinder is rotated and you can see through the outer one. At certain Reynolds http://en.wikipedia.org/wiki/Reynolds_number numbers you get different forms, such as a stream going helicaly around the cylinders, much like a barbers pole. I think this picture might be in Garrett's "Atmospheric Boundary Layers" book (no, I will not help you find it. That would be cheating and I don't get any of the royalties, so I don't care.).
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887321 = 337*2633
Spelling Nazis 1, Headlines 0.
Q: What did the comedian say to the crowd?
A: If I knew, this joke would be funny.
"Harry Swinney, a specialist in pattern-forming fluid flows at the University of Texas at Austin, says the new observation is roughly in line with what one might expect."
...yeah... the technical term.
Wahhh~? Specialist in pattern-forming fluid flows at University of Texas at Austin? Heck I hope Mr. Swinney's parents didn't flush their saving down the toilet on his college education... oops, I mean, symetrically pattern-forming spiral downward flowing.
"Don't let fools fool you. They are the clever ones."
Ex-NASA genius/nutball (you decide) Richard C. Hoagland has a page full of great pictures illustrating the above:
Hyperdimensional Hurricanes?
(does this explain crop circles too?)
Some better photos can be found here, along with a video. Unfortunately the video seems to show the vortex from its side rather than the top. Pretty cool though!
http://dcwww.camp.dtu.dk/~tbohr/RotatingPolygon/
I believe it was the Hatsopoulos lab that did this a few years ago. I'm looking for it now, but can anyone back me up?
Maybe they check for spelling errors in some <smartass>paralell</smartass> universe...
Program Intellivision!
I have one of those new powerful toilets and been studying this effect closely.
Venturing a guess that the speed that the false bottom is rotating at is related to the velocity that a vibration propagates through water, and the shapes are the result of resonance with the 'corners' nodes, and the edges antinodes.
Thoughts?
I wouldn't consider the mad hatter mad. Just reality impaired. He sure can make a mean cup of tea.
Does this remind anyone of Riven?
The above thread has been brought to you by your local chapter of Dictionary Nazis LTD.
Thank you.
GENERATION 667: The first time you see this, copy it into your sig on any forum and add 1 to the generation
So why the different shapes? As the bucket speeds up, three things happen. There's a different speed differential between the bucket and the water, the water depth decreases and the extra g forces increase (effectively increasing local gravity). This changes the wavelength of the wave. So, since the bucket has a finite circumference and is circular, standing waves will form that go back to their own starting point which will make shapes of integer numbers of sides. (non integer numbers of sides will not form a standing wave).
Engineering is the art of compromise.
This is a very obvious and crap "discovery" that is esily explained. No wonder it has not been reported widely. If anyone else had reported this they'd be laughed out of town, but there's the "ooooh he's Niels' grandchild... he **must** be bright" effect (like Bill Gates' kid showed off adding 2 + 2 = 4 on a calculator). I hope that this is not the highpoint of his professional career because that would just prove that even science is riddled with nepotism.
Engineering is the art of compromise.
who moderated this post Funny. Dumb guy doesnt even read the article and shoots off his mouth. Look at the effing pictures and you would know its not a triangle.
OMG I just realized the moderator might be laughing at his stupidity and thats why he/she moderated it Funny. Well its not kind to laugh at rednecks. its not their faults their Moms really loved their Brothers.
**Life is too short to be serious**
This reminds me of the work of the Swiss doctor Hans Jenny in the 60s. Dr. Jenny sent audible simple sine waves through various media and photographed the patterns that would emerge.
The results were often strikingly beautiful and symmetrical. His two books on the subject, full of high-quality imagery, were recently reprinted as one volume. He called his study of wave properties "cymatics."
The photographs illustrate the multi-sensory aspect of all phenomena. Frequency and wavelength show their existence in many forms and media, all representing the same phenomena. You can string a violin bow over sand on glass and see some incredible webs of patterns emerge in the sand. It's amazing to think that both aural and visual feedback from the same source can be produced so simply. And, importantly to myself at least, have both be aesthetically pleasing.
http://www.cymaticsource.com/ has the reprints of the books. I think they also relate it to a lot of more sketchy spiritual stuff that the good Dr. never mentioned AFAIK.
In this case in TFA, the researchers have seen the amazingly symmetrical and simple visual representation of the interaction between fluid, vessel, and frequency (rotation). It does make sense that such a simple phenomenon (rotating fluid) would have a simple, fundamental visual pattern. I bet it looks a lot more interesting than it sounds though.
"The researchers found that once the plate was spinning so fast that the water span out to the sides, creating a hole of air in the middle, the dry patch wasn't circular as might be expected."
If only English were so symmetrical. It's "spun".
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make install -not war
This reminds me of the unexpected patterns of Taylor-Couette instability that develop in the fluid between two rotating co-axial cylinders. Such patterns are similar to the bands on Jupiter.
Now someone go milk the beetles and give me a kortee'nea, I need to write some Ages badly :-) Oh, well, back to Povray it is then... :-P
Does this whole story sound just slightly suspicious? I don't spose it might be someone (again) trying to demonstrate the poor review standards of papers submitted to journals ...
... can't seem to get close to the effect described ... had a better chance of being electrocuted.
Having a big bucket and a variable speed drill coupled with a dodgey paint mixing device - I thought to try this. The mixer is 3 bladed and quite similiar to the rig in the pictures - I flattened out the blades so as to be pitchless and didn't operate propeller fashion.
I was pretty dissappointed and can only seem to make a big mess
Can anyone else make this work or am I alone in the world with my non geometric water?
of all of you.
SYMMETRICAL.
It's bad enough that the article title got it wrong, but most of the replies just followed suit.
-Activ
Nobel Peace prize!
Anyone? Anyone?
They're stoners. whoaaaa....
It's some kinda floating point rounding error, maybe god should switch to doubles.
Just one drawn on the hyperbolic plane. ;)
I've observed this effect using a "Zero Blaster" fog ring gun. The package indicated that "technique" was required for optimal performance, so I practiced and was eventually able to make super rings that were star-shaped and would travel faster, straighter (for a time), and further than an ordinary circular ring could. They also had other interesting properties...
I watched these super rings transition from their star-shape (usually 4 to 6 points) to an ordinary circular ring once enough energy had been lost to air friction. Upon "decaying" like this, the whole ring experiences severe turbulence - strong enough to eject parts of the ring from the body before it suddenly re-stabilizes as an ordinary circular smoke ring. It also abruptly changes direction (slightly) and continues to travel at a slightly reduced speed. The bucket experiment is quite different because it's externally powered and thus won't decay.
The ring decay phenomenon was very interesting to me and, combined with the star shapes, gave me the first clues about what's going on and I'm now sure of the solution and that it applies to the bucket experiment too. The theory I came up with was that two vortices are working together to create this effect. The primary vortex is, obviously, the toroidal flow of the smoke ring and the axial flow in the bucket. The secondary in both cases wraps around the primary like a candy cane and makes some number of complete turns around it so it meets-up with itself to form a stable closed-loop vortex.
The fact that regular geometry pops out of this should be no mystery then. Consider that the secondary vortex, however initiated, is likely powered & controlled by the primary and is thus bound to it. As it wraps around the primary, it must make a whole and complete number of turns around it or one of its up-flows will meet a down-flow and it negates its own energy, hence the turbulence and ejected fog during the decay process, which is simply when the secondary fails. Thus, you see what is stable and lasts and not those which don't - a conclusion of profound simplicity.
I noted other observational evidence supports the secondary vortex. In my experiments, this fog was heavier than air and because of that, ordinary circular rings begin to sag and eventually "drip" fog after a time. The fog contents of these star-shaped rings is clearly and visibly rotating axially (perpendicular to the primary) while traveling, however without rotating the ring itself (if you can imagine that - just the fog rotates within a non-rotating star-shaped ring) and keeps the ring from sagging - at least until the ring decays to an ordinary circle in the end anyway.
This theory could be perhaps be verified with a bucket experiment, which I will not attempt, by adding colored dye high-up or low-down and in a corner formed by the air gap opened up by the vortex. If there is a secondary vortex present, the dye should move from top to bottom and/or vice-versa quickly - before it reaches the next corner in fact, as each corner of the shape should represent a complete turn of the secondary vortex around the primary. These results would be interesting to know, but not so useful to me hehe.
Could the tri-star shape possibly in atmospheric conditions divide and therefore help explain multiple tornadoes spawning off from each other?
Like a city whose walls are broken down is a man who lacks self-control.
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True idiots will always amaze themselves.
Knowing Google's lust for data collection, the Soviet Union is still alive and well inside the psyche of Sergey Brin....
Neat this might give a way to measure viscosity of an atmostphere of a distant planet. On the other hand, might interfere with trying to identify ET constructions. Every regular polygon we find we are going to now start looking at whether there is some rotating fluid involved.
That noone thought of the obvious, So that's how they make holey water.
Ok, actually, now I typed it out I see why no one bothered.
There are some great videos of a similar behavior in a drop of mercury undergoing a cyclic surface reaction. It's a classic, called the "mercury beating heart." The drop will pulse in trianguloid and hexagonoid patterns. "Activity 5" is particularly good.
If only English were so symmetrical. It's either "span" or "spun" for the past tense (note, not for the past participle). Span is used less in American English.
=w=
no, it's span, the past tense of 'spin'. spin/span/spun
If only the Atlantic were so symmetrical. "Span" is described only as archaic when it's the past tense of spun, and not mentioned anywhere else, not even when listing conjugations of "to spin". Any citation of span as "past spin", so I don't sound archaic even elsewhere than America?
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make install -not war
I think you were wrong. Should I think you wrung?
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make install -not war
pedantic: adj 1: Like a pedant, overly concerned with formal rules and trivial points of learning; 2: Being showy of one's knowledge, often in a boring manner; 3: Often used to describe a person who emphasizes their knowledge through the use of vocabulary; 4: Being finicky or picky with language.
joke: n. 1. Something said or done to evoke laughter or amusement, especially an amusing story with a punch line. 2. A mischievous trick; a prank. 3. An amusing or ludicrous incident or situation.
recursion: n. Mathematics. 1. An expression, such as a polynomial, each term of which is determined by application of a formula to preceding terms. 2. A formula that generates the successive terms of a recursion.
recursion: n. Mathematics. 1. An expression, such as a polynomial, each term of which is determined by application of a formula to preceding terms. 2. A formula that generates the successive terms of a recursion.
This is not my sig.
If you spun the bucket and the rest of the universe around the false bottom instead, would you get the same results? ;-)
-Forrest Cameranesi, Geek of all Trades
"I am Sam. Sam I am. I do not like trolls, flames, or spam."
Well, when I said it was used less in American English I should perhaps have mentioned where it is used strongly: not so much in Britain as in the remnants of the old empire.
Wiktionary lists it as Australian English, and archaic elsewhere. Being a New Zealander I can say it's quite backed by usage here, as well as over the Tasman. Keeping with the less authorative sources, there's a mention in this article of "Australian speakers who use 'span' as the past tense of 'spin'", and this article (from a Malaysian English newspaper) mentions its use.
As far as more prescriptive sources are concerned, I've only got the concise version of the Oxford Dictionary of New Zealand handy which doesn't list most conjugations anyway. I guess I can say pretty confidently, though, that, amongst the 25 million-odd English speakers in Australasia, nobody would bat an eye upon hearing 'span'.
=w=
Why do not rotate a bucket instead of having a cylinder with a rotating bottom? They may have learned that the same thing happens. Or not --then publish. Why do not try a miriad of variables before publishing?
Comparing buckets of water to the formation and orbit of spacial objects gives new meaning to the phrase, "I live in a giant bucket."
In Soviet Russia, dot slashes YOU!
"When Adam delved and Eve span, who then was a gentleman?" Fr. John Ball, leader in the Peasant's Revolt of 1381
"Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery?" - Patrick Henry