Spiral-Defect Chaos (SDC) in Rayleigh-Benard convection:

What you need:

• Small Prandtl number ( ~1)
• Large aspect ratio ( >20)
• Moderate supercriticality ( 0.5..0.7)

What you get:

Morris, Bodenschatz, Cannel and Ahlers, 1993 , CO2	Assenheimer, Steinberg, 1993, SF4 near critical point

If you want to see SDC in motion, and have an MPEG player:

Here is an experimental movie of SDC from Eberhard Bodenschatz web site.

Here is our computer-generated SDC using Swift-Hohenberg equation coupled with mean flow