Open AccessJournal Article
Fire Whirl due to Interaction between Line Fire and Cross Wind
TLDR
In this paper, the authors presented an elementary study on a moving fire whirl by conducting line fire experiments with cross wind and found that a line fire near the ground, a reasonable attack angle between the line fire and the cross wind, and wind speed within a critical range are the three essential conditions for the formation of fire whir in a linefire.Abstract:
During the wildland fire of Brazil in 2010 (http://www.dailymail.co.uk/sciencetech/article-1306088/Braziltornado-Whirling-column-flames-sweeps-burning-fields.html), a special fire whirl occurred over a narrow but long fire front and moved due to the wind effect. This paper presents an elementary study on such a moving fire whirl by conducting line fire experiments with cross wind. Experimental analysis indicates that a line fire near the ground, a reasonable attack angle between the line fire and the cross wind, and wind speed within a critical range are the three essential conditions for the formation of fire whirl in a line fire. By examining the advection and bending of vorticity, it is also deduced that the concentrated vortex of fire whirl results from the coupling of the line fire plume and the horizontal vortex line near the ground surface. By assuming the solid-body rotation of fire whirl flame, a possible mechanism of moving fire whirl is proposed, which states that the flame moving is mainly controlled by the drag force, lift force and ground friction. Accurate experimental measurements are needed to testify or verify this mechanism in the future work.read more
Citations
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Journal ArticleDOI
Combustion dynamics of large-scale wildfires
TL;DR: In this paper, the authors present an overall pattern of the essential factors that lead an initial small-scale spreading flame to a large-scale wildfire beyond control, including the complicated transformation of fuel preheating mechanisms, varied large-size flame fronts and unique spread modes induced in specific fire environments.
Journal ArticleDOI
Effect of Wind on Fire Whirl Over a Line Fire
TL;DR: In this article, the authors present an experimental study on the fire whirls over a line fire with cross wind, focusing on the occurrence frequency of fire whirs, and propose a scaling law for the critical wind speed inducing fire whirs based on the experimental data in this work and literature.
Journal ArticleDOI
Effects of wind speed and heat release rate on the vortex strength and size of fire whirls without an inner core of flame
TL;DR: In this article, the effect of the crosswind speed and heat release rate (HRR) on the circulation, size, and velocity of a fire whirl was investigated at HHRs of 0.06-0.54 m/s.
Journal ArticleDOI
The interaction of double burner fire whirls
Katherine Hartl,Alexander Smits +1 more
TL;DR: In this article, a detailed description of double burner fire whirls is given, where two burners are placed symmetrically about the center of a fixed frame, and the flame from each burner sweeps along the ground until it reaches the point midway between the burners.
Journal ArticleDOI
Thermally-driven vortex resulting from the linear heat wires of different shapes under cross wind
TL;DR: In this article, the authors present an experimental study of the thermally-driven vortex induced by the linear heat wire under cross wind, where the straight, C-and S-shape wires were designed to simulate the fire front of different shapes and a wide range of heat release rate per length and wind speed were used to test the critical conditions under which vortex flows occur.
References
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Journal ArticleDOI
Effect of flow circulation on combustion dynamics of fire whirl
TL;DR: In this paper, the effect of flow circulation on the combustion dynamics of fire whirl is systematically investigated by experiments, and new correlations for the burning rate, flame height, radial temperature and mass flow rate are established.
Journal ArticleDOI
Scale-model experiments of moving fire whirl over a line fire
TL;DR: A fire whirl observed during a wildland fire in Brazil in 2010, occurred over a narrow but long line fire and moved along the line fire at nearly a constant speed.
Journal ArticleDOI
Formation of fire whirls: Experimental verification that a counter-rotating vortex pair is a possible origin of fire whirls
TL;DR: In this paper, it was shown that counter-rotating vortex pairs (CVPs) formed along and just downwind of a flame were occasionally shed downwind, and these vortices were a CVP of the plume of the flame.
Journal ArticleDOI
Flow structure in a fire tornado-like vortex
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