Spiral Defect Chaos Knitting Pattern
Spiral Defect Chaos
by Mary de Bruyn
photos of the sweater
how to knit the sweater
The sweater was made from a simple stockinette
cardigan pattern at a gauge of 20 stitches/4 inches.
To make a man's sweater that measures 50 inches all
around, cast on 62 stitches for each front and 125
for the back. The border of garter stitch was done
on smaller needles, then just continued straight. You
could use any basic sweater pattern, but avoid those
with waist shaping!
Any pixelated data would work, but you must remember
that knitting squishes images, because the stitches
are not square. You can find knitters' graph paper
online at several places, like
here. You can map out a section of pixels to see how your
data would look knitted.
In order to keep the continuity of the pattern, knit an extra
stitch at each edge for seaming, so that the convection
"flows" neatly around the sides.
download the convection pattern
- Full strip as a TIFF image.
- Strip broken into 6 pieces with enlarged pixels (TIFF images):
the science behind the pattern
The pattern is formed by temperature differences in pressurized CO2, which flows in a chaotic pattern when it is heated from below and cooled from above. The light areas are cool downward flowing fluid, and the dark areas are warm upflowing fluid.
- Here is the original 1993 publication on this effect. The sweater was made from a strip taken from Figure 2(b) of this paper.
- Here is a publication on the apparatus used in this experiment, and for many other interesting studies of convection in gases.
- Here is a definitive review paper on "Recent Developments in Rayleigh-Bénard Convection", by E. Bodenschatz, W. Pesch, and G. Ahlers, from Annual Review of Fluid Mechanics 32 : 709 (2000). [pdf 7MB].
- Here are more images of chaotic convection patterns, courtesy of Guenter Ahlers' group at Santa Barbara.
- Here is a link to the Göttingen pages on spiral defect chaos and other knit-worthy convection patterns.
- Here is a relatively nontechnical review article which appeared in Physics in Canada on gas convection experiments.
- Snapshot of spiral defect chaos.
- Mpeg movie of spiral defect chaos.
other art objects inspired by spiral defect chaos
A nice warm ski hat, knitted by Erica Bird.
A painted wooden pencil box, made by Erica Bird.
A painting entitled "Spiral Defect Chaos", by Martin Pearce, 1997.
The original is in the University of Toronto Art Centre. Interestingly, it contains no spirals.
- You can read Mary de Bruyn's knitting and travel blog "Knitting on the Cam", here, and leave comments.
- You can read more about pattern formation here.
The Experimental Nonlinear Physics Group, Dept. of Physics, University of
60 St. George St. Toronto, Ontario, Canada, M5S 1A7. Phone
978 - 6810.