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What the *** is tangential gravity??? 80.177.213.144 19:05, 19 Apr 2005 (UTC)
Now slightly rewritten to remove the phrase Linuxlad 13:50, 23 Apr 2005 (UTC)
Tangential gravity —Preceding unsigned comment added by Ayeroxor ( talk • contribs) 19:26, 23 April 2005
Fine, but not the preferred explanation for Labscale RT, I think —Preceding unsigned comment added by Linuxlad ( talk • contribs) 19:46, 23 April 2005
Shouldn't "which acts to break a cylindrical jet into a stream of droplets having the same volume but lower surface area" actually read "which acts to break a cylindrical jet into a stream of droplets having the same volume but greater surface area"? —Preceding
unsigned comment added by
71.53.8.184 (
talk •
contribs) 13:06, 26 July 2006
No... the Rayleigh limit indicates that if a cylinderical jet (radius R) of liquid is subjected to spatially periodic vericose surface perturbation of wavelength L, the perturbation will grow and the jet will break up into drops, even if the perturbation is of infinitesimal amplitude, so long as the wavelength of the perturbation exceeds the circumference of the unperturbed cylinder (i.e., L>2*Pi*R). Its easy to show that the lateral surface area of a cylinder (i.e., excluding the area of the ends) of raduis R and length L is greater than the surface area of a sphere of equivalent volume as long as L > 4.5R. Clearly, then, the surface area of the drops formed from the Rayleigh instability is less than the surface area of the one wavelength segments of the cylinder from which the drops are formed. —Preceding unsigned comment added by 128.46.120.153 ( talk • contribs) 19:47, 13 January 2007
The first place I ever heard of R-T instability (called just "Taylor Instability" at the time) was in the subject of nuclear weapons design. R-T occurs in the pit when the implosion shockwave crosses the border between two components, most notibily the uranium tamper and berylium reflector. Future re-writes of this article might reflect this. Reference: ( [1])
Also: Who were Rayleigh and Taylor. Is that the same Ted Taylor, the nuclear weapons designer.
Lord Rayleigh aka J. W. Strutt, and (Sir) Geoffrey Ingram Taylor - Taylor worked for UK MoD for a time and developed the 'shaped charge' where the metal cone flows like a fluid and forms an armour-piercing jet - he also worked on the Manhattan Project - HTH Linuxlad 08:50, 27 July 2006 (UTC).
Note that the RT instability is not to be confused with the Rayleigh instability (or Plateau-Rayleigh instability) of a liquid jet. This latter instability, sometime called the hosepipe (or firehose) instability, occurs due to surface tension, which acts to break a cylindrical jet into a stream of droplets having the same volume but lower surface area. This reference: Actual images and videos of RT fingers ends with "Manifestations of Rayleigh-Taylor instability," which actually illustrates Plateau-Rayleigh instability. Something's gotta give. - AndromedaRoach 03:19, 17 December 2006 (UTC)
http://arxiv.org/abs/physics/0610082 According to secion 5 of the reference, (see page 9), some "Rayleigh theorem" is incorrect. I don't know of this is the place for that, but there can't be too many Rayleigh's in the field of Fluid Dynamics, so they are probably talking about the same man, even if it isn't quite the same instability. Crysta1c1ear 03:28, 8 January 2007 (UTC)
This reference, categorically, does not refer to either the Rayleigh-Taylor instability or the Rayleigh instability —Preceding unsigned comment added by 128.46.120.153 ( talk • contribs) 19:02, 13 January 2007
I added a reference to Chandrasekhar's book and removed the 'need citations' tag from the linear stability section. I hope this is a sufficient reference. I think this is standard wikipedia policy for mathematical articles, since this entire section is self-verifiable in the sense that it's a mathematical theorem. Otherwise it would be cumbresome to add a reference at the end of every line where a mathematical statement is made. Onaraighl ( talk) 16:39, 28 June 2008 (UTC)
So, who added their brand-spanking new paper on something extremely tangential to the discussion as the last source? Talk about ego-stroking and NPOV violation... 68.54.135.8 ( talk) 04:30, 28 May 2012 (UTC)
The name of Chandrasekhar's book is Hydtrodynamic and Hydromagnetic Stability. It took me some time to find it with the wrong name. Can anyone help me fix it? I don't know how to edit citation. Thanks! BTW, I was talking about the citation number 9.
It used to say "a dense, heavy fluid is being accelerated by light fluid" (which is correct), until an anonymous user changed it. It should say either the dense one is being accelerated by the light one, or the light one is being accelerated into the dense one. What we have now is totally backwards and doesn't describe any instability.
If you're confused, maybe it's because the gravitational field at the Earth's surface points down, which means that (by the E.P.) the Earth's surface is in a frame accelerating upwards. They go opposite ways. — Keenan Pepper 13:14, 10 July 2008 (UTC)
In my opinion the lead is improving a lot. There remain two problems which I have with the first sentence:
I studied physics as an undergraduate not too horribly long ago, and I can't make heads or tails of the third paragraph in the introduction to this page. It seems like we're jumping into some very technical stuff without providing some sort of introduction to it or even linking to the relevant pages. Cww ( talk) 04:39, 5 May 2009 (UTC)
Just an idea: It might be useful to include some mention of a lava lamp in this article, as a real-life example of an unstable fluid mechanical system. I'm not sure how appropriate an example it would be, though. Perhaps someone more expert in fluid mechanics would have a better opinion. CosineKitty ( talk) 20:36, 10 August 2011 (UTC)
The curl of an irrotational velocity field (i.e., ), which is also solenoidal (i.e., ) does not, in general, satisfy , where is the stream function satisfying . In general, . On the other hand, for an irrotational and solenoidal vector field, the velocity potential () can be shown to satisfy Laplace's equation, . What other assumptions were made in the actual derivation such that , assuming this is correct? – Roche398 ( talk) 16:19, 6 July 2013 (UTC)
"This instability, sometimes called the hosepipe (or firehose) instability, occurs due to surface tension, which acts to break a cylindrical jet into a stream of droplets having the same volume but lower surface area." When an object is broken into multiple pieces, they usually have greater surface area than the original object. WilliamSommerwerck ( talk) 23:18, 3 May 2014 (UTC)
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What the *** is tangential gravity??? 80.177.213.144 19:05, 19 Apr 2005 (UTC)
Now slightly rewritten to remove the phrase Linuxlad 13:50, 23 Apr 2005 (UTC)
Tangential gravity —Preceding unsigned comment added by Ayeroxor ( talk • contribs) 19:26, 23 April 2005
Fine, but not the preferred explanation for Labscale RT, I think —Preceding unsigned comment added by Linuxlad ( talk • contribs) 19:46, 23 April 2005
Shouldn't "which acts to break a cylindrical jet into a stream of droplets having the same volume but lower surface area" actually read "which acts to break a cylindrical jet into a stream of droplets having the same volume but greater surface area"? —Preceding
unsigned comment added by
71.53.8.184 (
talk •
contribs) 13:06, 26 July 2006
No... the Rayleigh limit indicates that if a cylinderical jet (radius R) of liquid is subjected to spatially periodic vericose surface perturbation of wavelength L, the perturbation will grow and the jet will break up into drops, even if the perturbation is of infinitesimal amplitude, so long as the wavelength of the perturbation exceeds the circumference of the unperturbed cylinder (i.e., L>2*Pi*R). Its easy to show that the lateral surface area of a cylinder (i.e., excluding the area of the ends) of raduis R and length L is greater than the surface area of a sphere of equivalent volume as long as L > 4.5R. Clearly, then, the surface area of the drops formed from the Rayleigh instability is less than the surface area of the one wavelength segments of the cylinder from which the drops are formed. —Preceding unsigned comment added by 128.46.120.153 ( talk • contribs) 19:47, 13 January 2007
The first place I ever heard of R-T instability (called just "Taylor Instability" at the time) was in the subject of nuclear weapons design. R-T occurs in the pit when the implosion shockwave crosses the border between two components, most notibily the uranium tamper and berylium reflector. Future re-writes of this article might reflect this. Reference: ( [1])
Also: Who were Rayleigh and Taylor. Is that the same Ted Taylor, the nuclear weapons designer.
Lord Rayleigh aka J. W. Strutt, and (Sir) Geoffrey Ingram Taylor - Taylor worked for UK MoD for a time and developed the 'shaped charge' where the metal cone flows like a fluid and forms an armour-piercing jet - he also worked on the Manhattan Project - HTH Linuxlad 08:50, 27 July 2006 (UTC).
Note that the RT instability is not to be confused with the Rayleigh instability (or Plateau-Rayleigh instability) of a liquid jet. This latter instability, sometime called the hosepipe (or firehose) instability, occurs due to surface tension, which acts to break a cylindrical jet into a stream of droplets having the same volume but lower surface area. This reference: Actual images and videos of RT fingers ends with "Manifestations of Rayleigh-Taylor instability," which actually illustrates Plateau-Rayleigh instability. Something's gotta give. - AndromedaRoach 03:19, 17 December 2006 (UTC)
http://arxiv.org/abs/physics/0610082 According to secion 5 of the reference, (see page 9), some "Rayleigh theorem" is incorrect. I don't know of this is the place for that, but there can't be too many Rayleigh's in the field of Fluid Dynamics, so they are probably talking about the same man, even if it isn't quite the same instability. Crysta1c1ear 03:28, 8 January 2007 (UTC)
This reference, categorically, does not refer to either the Rayleigh-Taylor instability or the Rayleigh instability —Preceding unsigned comment added by 128.46.120.153 ( talk • contribs) 19:02, 13 January 2007
I added a reference to Chandrasekhar's book and removed the 'need citations' tag from the linear stability section. I hope this is a sufficient reference. I think this is standard wikipedia policy for mathematical articles, since this entire section is self-verifiable in the sense that it's a mathematical theorem. Otherwise it would be cumbresome to add a reference at the end of every line where a mathematical statement is made. Onaraighl ( talk) 16:39, 28 June 2008 (UTC)
So, who added their brand-spanking new paper on something extremely tangential to the discussion as the last source? Talk about ego-stroking and NPOV violation... 68.54.135.8 ( talk) 04:30, 28 May 2012 (UTC)
The name of Chandrasekhar's book is Hydtrodynamic and Hydromagnetic Stability. It took me some time to find it with the wrong name. Can anyone help me fix it? I don't know how to edit citation. Thanks! BTW, I was talking about the citation number 9.
It used to say "a dense, heavy fluid is being accelerated by light fluid" (which is correct), until an anonymous user changed it. It should say either the dense one is being accelerated by the light one, or the light one is being accelerated into the dense one. What we have now is totally backwards and doesn't describe any instability.
If you're confused, maybe it's because the gravitational field at the Earth's surface points down, which means that (by the E.P.) the Earth's surface is in a frame accelerating upwards. They go opposite ways. — Keenan Pepper 13:14, 10 July 2008 (UTC)
In my opinion the lead is improving a lot. There remain two problems which I have with the first sentence:
I studied physics as an undergraduate not too horribly long ago, and I can't make heads or tails of the third paragraph in the introduction to this page. It seems like we're jumping into some very technical stuff without providing some sort of introduction to it or even linking to the relevant pages. Cww ( talk) 04:39, 5 May 2009 (UTC)
Just an idea: It might be useful to include some mention of a lava lamp in this article, as a real-life example of an unstable fluid mechanical system. I'm not sure how appropriate an example it would be, though. Perhaps someone more expert in fluid mechanics would have a better opinion. CosineKitty ( talk) 20:36, 10 August 2011 (UTC)
The curl of an irrotational velocity field (i.e., ), which is also solenoidal (i.e., ) does not, in general, satisfy , where is the stream function satisfying . In general, . On the other hand, for an irrotational and solenoidal vector field, the velocity potential () can be shown to satisfy Laplace's equation, . What other assumptions were made in the actual derivation such that , assuming this is correct? – Roche398 ( talk) 16:19, 6 July 2013 (UTC)
"This instability, sometimes called the hosepipe (or firehose) instability, occurs due to surface tension, which acts to break a cylindrical jet into a stream of droplets having the same volume but lower surface area." When an object is broken into multiple pieces, they usually have greater surface area than the original object. WilliamSommerwerck ( talk) 23:18, 3 May 2014 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on Rayleigh–Taylor instability. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
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