Universal Fire Shape and Whirls

Explore the basis of the universal fire shape as well as twirl and burst
behavior. In this wildfire simulation, as the fire spreads, it evolves into a
shape well-known to fire managers. The "head" is the leading edge of the fire
where the heat is focused. Along the side are two "flanks", where the winds
blow parallel to the edge of the fire. The "Back" is the slowest moving part of
the fire and creeps against the wind. In addition, an animation of the vertical
vorticity (rotation of air) shows the presence of fire whirls. Wildfires can
contain fire whirls of greatly varied intensity, duration and size - from a few
meters in diameter, to where the entire smoke-filled updraft (perhaps 1 km
wide) is rotating. Most are small, but they have been known to break off trees
more than a meter in diameter.