大火災に伴う旋風について

Abstract

The posibility of the occurrence of vortices associated with a large fire is discussed. Character-istics of the fire vortices which occurred in the past are reviewed, and necessary conditions to produceconcentrated vortices over or around the fire is discussed. A laboratory simulation to investigatethe criteria of the vortex core formation is carried out. It is found that either the high temperatureof the ground surface or large inflow angle produces the concentrated vortices, and also that theseconditions are probable in case of a large fire. It is also found that the core temperature of theproduced vortex core increases with the inflow angle.