Firestorms
Quantitative criteria are sought for onset of firestorms, severe stationary (nonpropagating) holocausts arising via merger of fires from multiple simultaneous ignitions in a heavily fuel-laden urban environment. Within an hour, surface-level radial inflow from all directions sustains a large-diameter convective column that eventually reaches altitude of about 10 km (e.g., Hamburg, Dresden, Hiroshima). As the firestorm achieves peak intensity (a couple of hours after the ignitions), inflow speeds are inferred to attain 25-50 m/s; typically 12 km/sup 2/ are reduced to ashes, before winds relax to ambient levels in six-to-nine hours. Here the firestorm is interpreted to be a mesocyclone (rotating severe local storm). Even with exceedingly large heat release sustained over a concentrated area, in the presence of a very nearly autoconvectively unstable atmospheric stratification, onset of vigorous swirling on the scale of two hours requires more than concentration of circulation associated with the rotation of the earth; rather, a preexisting, if weak, circulation appears necessary for firestorm cyclogenesis.
- Research Organization:
- TRW Space and Technology Group, Redondo Beach, CA
- OSTI ID:
- 5237232
- Report Number(s):
- CONF-830702-
- Journal Information:
- HTD (Publ.) (Am. Soc. Mech. Eng.); (United States), Journal Name: HTD (Publ.) (Am. Soc. Mech. Eng.); (United States) Vol. HTD-VOL 25; ISSN ASMHD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
42 ENGINEERING
420400 -- Engineering-- Heat Transfer & Fluid Flow
ASHES
ASIA
CONVECTION
EARTH PLANET
ENERGY TRANSFER
FIRES
FLAME PROPAGATION
FLUID FLOW
HEAT TRANSFER
HIROSHIMA
IGNITION
JAPAN
MOTION
PLANETS
RESIDUES
ROTATION
STRATIFICATION
URBAN AREAS
VELOCITY
VORTEX FLOW
WIND