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Vortex rings are a familiar site. Perhaps the best known example are the smoke rings that smokers make. However, there are many other examples. Dolphins make air vortex rings in the water and play games with them. See the web site: http://www.sciam.com/0896issue/0896dolphins.html to find out more about that as well as the article, "Ring Bubbles of Dolphins" by Ken Marten, Karim Shariff, Suchi Psarakos and Don J. White in "Scientific American", August 1996. Vortex rings can also be found when charged particles travel through superfluid helium. The "Scientific American article by F. Reif, "Quantized Vortex Rings in Superfluid Helium", December 1964 is an excellent introduction to this.
SPS made a number of different sized votex ring generators. We filled them with the smoke from a fog machine in order to see the rings. To make your own vortex ring generator out of a coffee can, see the December 1965 issue of Scientific American pages 109-113.
We followed Bill Grundmann's plans for making a giant vortex ring generator. You can visit his site at: http://bill.kats22.com/vger/index.html
We studied how the speed of the rings depends upon the diameters. Our results are pretty crude because the speed is clearly dependent upon how fast one pushes the sheath. For example, we could almost double the speed of the 0.9 m rings by pushing harder. Below is a plot of our results. We tried to keep the push on the sheath constant.
We also took some movies and photos. The rings travelled well over 50 feet. (see below)
We took the vortex generator outside late December for a test. Below are two QuickTime movies and a still photo.
Filling in some cracks and sanding it on 12/04/01.
The vortex generator is looking good. Below are three photos from 11/21/01.
We can easily seperate it into 2 parts. (This is necessary since whole, it's too large to fit through the door.)
Below is a photo taken on 10/26/01, of Fadi and Les in the middle of building it.