Trajectory of firebrands in and out of fire whirls

Modeling forest fire spread and spotting process with small world networks

“…Crown fires can be excellent generators of embers for spotting. Although lofting and propagation of burning brands in forest fires have received considerable attention ( [18][19][20][21][22][23], to name but a few), very little research has been conducted to study the role of firebrands on the propagation of the fire itself. To our knowledge, the only study that attempts to estimate such influence is that of Hargrove et al [24], who used a broad-scale probabilistic model of forest fires burning through heterogeneous landscapes.…”

Modeling transport and combustion of firebrands from burning trees

“…Muraszew and Fedele [5] modeled two-dimensional trajectories of cylindrical firebrands released above a fire whirl. The firebrand combustion model required the time evolution of both density and diameter.…”

The Spotting Distribution of Wildfires

“…When conditions aloft are favorable for strong convection column development [15], or large-scale fire-induced vortices (fire whirls) exist [16], spotting may contribute significantly to a fire's spread. A spot fire 29 km downwind of an existing fire in Victoria, Australia appears to be the longest recorded spot fire event [11].…”

“…Experimental analysis on the Aerospace Corporation's experiments, appearing in [16], revealed that for the cylindrical firebrands in the study the mass m(t) is related to the terminal velocity v(t) according to: Several combustion models have been proposed in the literature, and the interested reader is invited to peruse the review in [7]. They are usually modeled as continuous-time processes, so we will present functional forms for the density, effective radius, or simply the mass as functions of time.…”

“…The lower the FFMC, the higher the fine fuel moisture content. Experiments by the Aerospace Corporation [16,43] found that for high fine moisture contents only large flaming brands cause ignition, while for low fine fuel moisture content glowing embers may easily ignite a fuel bed. Albini [13] reports that spotting can be significant when fine fuel moisture content is below ten percent, and confirmed the earlier results by [43] that glowing embers can be sources of ignition.…”