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| Titel |
Modelling wildland fire propagation by tracking random fronts |
| VerfasserIn |
G. Pagnini, A. Mentrelli |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Sciences ; 14, no. 8 ; Nr. 14, no. 8 (2014-08-28), S.2249-2263 |
| Datensatznummer |
250118613
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| Publikation (Nr.) |
 copernicus.org/nhess-14-2249-2014.pdf |
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| Zusammenfassung |
| Wildland fire propagation is studied in the literature by two alternative
approaches, namely the reaction–diffusion equation and the level-set method.
These two approaches are considered alternatives to each other because the
solution of the reaction–diffusion equation is generally a continuous smooth
function that has an exponential decay, and it is not zero in an infinite
domain, while the level-set method, which is a front tracking technique,
generates a sharp function that is not zero inside a compact domain. However,
these two approaches can indeed be considered complementary and reconciled.
Turbulent hot-air transport and fire spotting are phenomena with a random nature and
they are extremely important in wildland fire propagation.
Consequently, the fire front gets a random character, too; hence, a tracking
method for random fronts is needed. In particular, the level-set contour is
randomised here according to the
probability density function of the interface particle displacement.
Actually, when the level-set method is developed for tracking a front
interface with a random motion, the resulting averaged process emerges to be
governed by an evolution equation of the reaction–diffusion type. In this
reconciled approach, the rate of spread of the fire keeps the same key and
characterising role that is typical of the level-set approach. The resulting
model emerges to be suitable for simulating effects due to turbulent
convection, such as fire flank and backing fire, the faster fire spread being
because of the actions by hot-air pre-heating and by ember landing, and also
due to the fire overcoming a fire-break zone, which is a case not resolved by models based on the
level-set method. Moreover, from the proposed formulation, a correction follows
for the formula of the rate of spread which is due to the mean jump length of
firebrands in the downwind direction
for the leeward sector of the fireline contour. The presented
study constitutes a proof of concept, and it needs to be subjected to a future validation. |
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