Fire Propagation (fire + propagation)

Distribution by Scientific Domains


Selected Abstracts


Note on the determination of the ignition point in forest fires propagation using a control algorithm

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 11 2008
M. Bergmann
Abstract This paper is devoted to the determination of the origin point in forest fires propagation using a control algorithm. The forest fires propagation are mathematically modelled starting from a reaction diffusion model. A volume of fluid (V.O.F.) formulation is also used to determine the fraction of the area which is burnt. After having developed the objective functional and its derivative, results from an optimization process based on the simplex method is presented. It is shown that the ignition point and the final time of the fire propagation are precisely recovered, even for a realistic, non-horizontal, terrain. Copyright © 2007 John Wiley & Sons, Ltd. [source]


A spatial model of coexistence among three Banksia species along a topographic gradient in fire-prone shrublands

JOURNAL OF ECOLOGY, Issue 5 2002
J. Groeneveld
Summary 1A spatially explicit, rule-based model for three co-occurring Banksia species was developed to investigate coexistence mediating processes in a fire-prone shrubland in western Australia. Fecundity, recruitment, mortality and other biological data for two non-sprouting (B. hookeriana, B. prionotes) and one resprouting (B. attenuata) species were available from 15 years of empirical field studies. 2Without interspecific competition, each species could persist for a wide range of fire intervals (10 to > 20 years). The resprouting species performed better under shorter fire intervals (10,13 years), while both non-sprouting species were favoured by longer (15 to > 20 years) fire intervals. These results conform with those obtained from single-species, non-spatial population models. 3When interspecific competition for space was included in the model, all three species exhibited optima at shorter fire intervals and with a narrower range than in isolation. The three species did not co-occur under any fire regime. At intermediate fire frequencies (11,13 years), B. hookeriana excluded the other species, while for longer intervals between fires B. prionotes became dominant. 4The introduction of temporal (stochastic) variability in fire intervals (drawn from a normal distribution) failed to produce coexistence, unless spatial variability as a spatial ignition gradient was also included. The spatial arrangement of the non-sprouters observed in the field was then reproduced. 5Observed patterns of coexistence and spatial distributions of all species occurred when a spatial establishment gradient for the resprouter species was included in the model (individuals of B. attenuata are known to produce more seeds in swales than on dune crests and recruit seedlings here more frequently). 6Coexistence appears to be highly dependent upon the mean interfire period in combination with subtle gradients associated with fire propagation and recruitment conditions. Variation around the mean fire interval is less critical. When the system is modelled over a long time period (1500 years) coexistence is most strongly favoured for a narrow window of mean fire intervals (12,14 years). [source]


Implications of foliar terpene content and hydration on leaf flammability of Quercus ilex and Pinus halepensis

PLANT BIOLOGY, Issue 1 2008
G. A. Alessio
Abstract We investigated the implications of foliar hydration and terpene content on leaf flammability in two widely distributed forest species of the Mediterranean basin, Quercus ilex, which does not store terpenes, and Pinus halepensis, a terpene-storing species. The experiments were carried out in plants grown under different water regimes that generated a wide range of foliar hydration and terpene contents. We monitored the temperatures and time elapsed to reach the smoke, pyrolysis and flame phases. Smoke appeared much earlier (37 versus 101 s) and at lower temperatures (96 versus 139 °C) in Quercus ilex than in Pinus halepensis. Quercus ilex reached pyrolysis earlier than Pinus halepensis (278 versus 338 s) but at the same temperature (365,371 °C). There were no significant differences in time elapsed nor in temperature for flammability (386,422 s; 505,487 °C in both species). Quercus ilex had lower water hydration than Pinus halepensis (41 versus 100%) and the leaf content of terpenes in Quercus was three orders of magnitude lower. The results of this study show no differences in the flame phase between the two species and the absence of a significant relationship between temperature and elapsed time of the different flammability phases in relation to monoterpene content; thus indicating that the role of monoterpenes in flammability phases is smaller than that of the water content. This, however, does not exclude the effects of terpene content on plant combustibility and fire propagation once fires start. [source]


Investigation of the Development of Conflagration of Solid Material via Analysis of Coupled Heat, Mass and Momentum Transport

CHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 2 2009
U. Krause
Abstract A mathematical model is presented for the transport of heat, mass and momentum transfer through a porous medium to simulate the chain of events from self-heating, subsequent self-ignition to smouldering fire propagation and burn-out of combustible fractions. The model comprises both diffusive and convective transport. The chemical reaction sub-model includes solid fuel decomposition and the combustion of char, carbon monoxide and hydrogen. Furthermore, biological processes, which may be a precursor of self-heating and vaporization/condensation of moisture, are also included into the model. All input data necessary for implementing the model have been determined experimentally. The model has been validated against laboratory scale self-ignition and smouldering propagation experiments and then applied to predictions of different fire scenarios during storage of bulk materials. [source]


Note on the determination of the ignition point in forest fires propagation using a control algorithm

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 11 2008
M. Bergmann
Abstract This paper is devoted to the determination of the origin point in forest fires propagation using a control algorithm. The forest fires propagation are mathematically modelled starting from a reaction diffusion model. A volume of fluid (V.O.F.) formulation is also used to determine the fraction of the area which is burnt. After having developed the objective functional and its derivative, results from an optimization process based on the simplex method is presented. It is shown that the ignition point and the final time of the fire propagation are precisely recovered, even for a realistic, non-horizontal, terrain. Copyright © 2007 John Wiley & Sons, Ltd. [source]