Rotating Water Polygons
Date: Tuesday, May 16, 2006 @ 13:03:44 MST
A team from Technical University of Denmark has
generated very unusual dynamic structures in a cylinder of water. A
rotating plate inside the water-filled cylinder induces a whirl that
develops into stable symmetric shapes, such as pentagons or hexagons
that also rotate.
This reminds cymatics and shape generation via resonant frequencies within a given medium.
The unusual phenomenon in question involves
rotating a bottom plate under a liquid in a circular (cylindrical)
container. Bohr and his team of students at the Technical University
and at the Niels Bohr Institute set up an experiment to find out
whether or not such conditions would lead to stable deformations of a
water surface into polygon shapes. The findings from their experiment
were published May 3rd in Physical Review Letters.
Bohr tells PhysOrg.com that a somewhat
similar experiment took place eight years ago with a different team
(including Clive Ellegaard and others). “We had fluid falling on a
plane, like water from a faucet. We found that even if the rim of the
plate is completely circular, the fluid surface can be shaped like a