This false color image shows a spiral-shaped flame that formed on a heated spinning disk, contrary to the expectation of a circular flame.
From bonfires to match sticks, flames usually have simple, predictable shapes. But, researchers recently described a completely unexpected burning pattern: spiral shaped flames on the surface of a burning, spinning disk. Although spiral patterns have been seen in a wide range of chemical and biological burning systems, no one had observed them amongst the complex flows of mixing gases that occur when the fuel and oxygen molecules must diffuse to find one another. The experiments may provide the first opportunity to derive spiral patterns from basic physics equations--a feat that has so far eluded researchers studying spirals in other systems.