Vortex

A vortex (pl. vortices) is a spinning, often turbulent, 
flow of fluid. The motion of the fluid swirling rapidly around a center is called a vortex. The speed and rate of rotation of the fluid are greatest at the center and become smaller with distance from the center.

Related pages
 Vorticity
 Wormhole

Other websites

Dust Devil Movie A short movie showing many spinning vortices of varying sizes
Video of two water vortex rings colliding  (MPEG)
BubbleRings.com Web site on "bubble rings", which are underwater rings made of air formed from vortices. The site has some information on how these rings work.
Chapter 3 Rotational Flows: Circulation and Turbulence 
Video of Vortex Formation and Annihilation in a Superconductor (By Joel Thorarinson )

Category:Fluid mechanics