I am not happy to have my thread hijacked and spoofed. So, at the risk of my seeming to be a bad sport, could we just pick it up from here? I think you guys are right on the edge of troll-dom here. My worst fear is that because I don’t really know what spoofing is, I will inadvertently send something to somebody that will up set them and demean the list.
Returning to SS’s serious post,
SS wrote è the actual rate of swirling, size of vortex, etc, is limited by the water viscosity and the pressure (head) methinks. Stephen is saying "symmetry break! symmetry break!" and I'm nodding in agreement that without the symmetry break, the water just gurgles on down. In the water-bottle swirl example, it is exaggerated because there is fluid trying to get into the bottom bottle against a counter flow of air... and the surface tension adds to the obstruction in the non-swirlie regime. ç SS wrote.
I have always had trouble with the notion of symmetry breaking. It seems to me that what the system does is trade one asymmetry for another … . I am not sure about the sink situation, but in the benard cell situation the gradient of heat from bottom to top (a vertical assymmetry) is traded for the lateral asymmetry imposed by the convective cells.
To be honest, I hadn’t thought of the counter flow of air. But isn’t that why sewage systems are designed with evacuating pipes … so the descending water does NOT encounter a counter flow?
Nicholas S. Thompson
Emeritus Professor of Psychology and Biology
Clark University
http://home.earthlink.net/~nickthompson/naturaldesigns/
http://www.cusf.org
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