Talk:Plateau–Rayleigh instability

I would like to thank the contributer(s) for a very well written article.

I have, however, a small comment regarding "Later, Rayleigh showed theoretically that a vertically falling column of non-viscous liquid with a circular cross-section should break up into drops if its wavelength exceeded its circumference, or Pi times its diameter."

It was Plateau and not Rayleigh who showed theoretically that the a jet with a circular cross section becomes unstable if it is subjected to a pertubation with wavelength longer the perimeter of its cross section (See Experimental and theoretical statics of liquid fluids subject to molecular forces only. University of Gent, 1873). The argument in this article with pressure difference between troughs and peaks is also due to him. Based on this Plateau assumed that the jet will break up into segment of (pi D)D.

Rayleigh showed that this last conclusion is not correct. He argued, as you do in this article, that it is not the shortest (pi D ~ 3.14 D) but the fastest unstable mode, which he found to be ~ 4.51 D, that determines the volume of the segments.

Tarek.a.yousef (talk) 11:58, 7 January 2012 (UTC)

Wavelength in a stream? What is it?

 * "In 1873, Plateau found experimentally that a vertically falling stream of water will break up into drops if its wavelength is greater than about 3.13 to 3.18 times its diameter."

What exactly is the wavelenght of a stream? Its not mentioned again in the article nor explained.

--Eheran (talk) 08:29, 23 February 2018 (UTC)


 * Yes, it should be "length", not "wavelength", so it has been fixed. David C Bailey (talk) 15:57, 17 January 2022 (UTC)