The Right Coast

Editor: Thomas A. Smith
University of San Diego
School of Law

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Wednesday, November 6, 2013

BBC News - Physicists probe urination 'splashback' problem

One might think the physics of aiming urination had already been summarised by the formula: "get it all in the bowl". But micturation is still a messier business than it needs to be, according to the research.


I prefer the old fashioned sort of bog that is built partially into the floor. Another example of "progress."

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These physicists need to do a lot more study, starting with the 1895 (or so) paper by Lord Rayleigh that showed that, because of unavoidable ambient vibrations, a stream of water that starts as a column quickly breaks up into large droplets joined by a finer column, which in turn breaks up into tiny droplets, which, because they bounce back and forth, hitting each other and the larger droplets, end up being cast outward, far from the original column.

There is no amount of aiming that the stehpinkler can do to avoid this: the floor will get wet.

In the same paper, Rayleigh showed that forced vibration of the nozzle (a traditional male motion that can be enhanced by mechanical means) will regularize the droplet sizes according to Bessel harmonics, which will improve the stream but not entirely eliminate spray and splatter.

Posted by: Jimbino | Nov 6, 2013 4:05:26 PM