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Author(s):
Masahiko Shinohara, Sanae Matsushima
Year Published:

Cataloging Information

Topic(s):
Fire Behavior
Extreme Fire Behavior

NRFSN number: 19203
FRAMES RCS number: 57013
Record updated:

Laboratory experiments were conducted to determine whether stationary fire whirls just downwind of a meter-scale turbulent flame are the lowest part of the counter-rotating vortex pair (CVP) of the plume from the flame. Plumes from a turbulent pool fire and air flow around the fire were visualized. There are two types of stationary fire whirls: those that contain flames (FWflame) and those that do not (FWair). We determined that FWairis most likely the lowest part of the CVP and that FWflame is most likely generated by flames entering the lowest part of the CVP, swirling and increasing in length. FWairs and FWflames form alternately at the same location just downwind of the fuel pools. During the period when stationary fire whirls occur, the plume tilt angle from the vertical direction is smaller, and the variation in the plume tilt angle and flame trailing length is greater compared to all other periods. Flow visualization also showed that the characteristic semi-circular space (SCS) partly surrounded by the flame trailing downwind from both edges of the fuel pools is generated by the swirling wind of FWairs inside the SCS.

Citation

Shinohara, Masahiko; Matsushima, Sanae. 2019. Flow visualization study of stationary fire whirls just downwind of meter-scale turbulent flames. Flow, Turbulence and Combustion online early.

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