Firestorms

The expansion of firestorms
Different scaling laws apply for calculating the heat and incinerating effects
from bomb yield. Fire advances by wind driven heat propagation. In a
uniform atmosphere without turbulent or convective processes the
expansion would follow an exponential law with the radiation absorption
parameter κ. The heat exposure at distance d would be:
Q
=
W
4π
⋅ d
therm
2
⋅e
−κ
⋅d
For turbulent firestorms empirical approximations are used to describe
transmittance of heat in terms of the transmittance factor τ (empirical
factor for visibility) and f the thermal heat fraction of total energy release
(f ≈ 0.35-0.42 depending on altitude).
Q
=
Wtherm
⋅τ
4π
⋅ d
f ⋅W
⋅τ
4π
⋅ d
f ⋅W
⋅τ
4π
⋅ d
12
= = 10 ⋅ cal /
2 2
2
cm
2