Experimental analysis of fire spread across a two-dimensional ridge under wind conditions

2015 ◽  
Vol 24 (7) ◽  
pp. 1008 ◽  
Author(s):  
J. R. Raposo ◽  
S. Cabiddu ◽  
D. X. Viegas ◽  
M. Salis ◽  
J. Sharples
Keyword(s):  
Flow Velocity ◽  
Forest Fires ◽  
Experimental Analysis ◽  
Dynamic Effect ◽  
Fire Spread ◽  
Laboratory Scale ◽  
Lateral Spread ◽  
Two Dimensional ◽  
Vortex Strength ◽  
Fire Spreading

Results from a laboratory-scale investigation of a fire spreading on the windward face of a triangular-section hill of variable shape with wind perpendicular to the ridgeline are reported. They confirm previous observations that the fire enlarges its lateral spread after reaching the ridgeline, entering the leeward face with a much wider front. Reference fire spread velocities were measured and analysed, putting in evidence the importance of the dynamic effect due to flow velocity and its associated horizontal-axis separation vortex strength without dependence on hill geometry. Similar parameters estimated from three forest fires compared favourably with the laboratory-scale measurements.

Preliminary Study of Fire Spread in Cities and Forests, Using PMMA Specimen as a Fuel in CFD Simulations

2009 ◽  
Author(s):  
Koyu Satoh ◽  
Naian Liu ◽  
Qiong Liu ◽  
K. T. Yang
Keyword(s):  
Laboratory Experiment ◽  
Forest Fires ◽  
Three Dimensional ◽  
Fire Spread ◽  
Weather Data ◽  
Strong Wind ◽  
Cfd Simulations ◽  
Worst Case ◽  
Fire Propagation ◽  
Fire Spreading

It is important to examine the behavior of forest fires and city fires to mitigate the property damages and victims by fires. There have been many previous studies on forest fires where the fire spreading patterns were investigated, utilizing artificial satellite pictures of forest fires, together with the use of corresponding weather data and GIS data. On the other hand, large area city fires are very scarce in the world, particularly in modern cities where high-rise concrete buildings are constructed with sufficient open spaces. Thus, the examples of city fires to be referred are few and detailed investigations of city fires are limited. However, there have still been existing old cities where traditional houses built with flammable material such as wood, maybe historically important, only separated with very small open spacing. Fires may freely spread in those cities, once a big earthquake happens there and then water supply for the fire brigade is damaged in the worst case along with the effect of strong wind. There are some fundamental differences between the forest fires and city fires, as the fuel may distribute either continuously or discretely. For instance, in forest fires, the dead fallen leaves, dry grasses and trees are distributed continuously on the ground, while the wooden houses in cities are discretely distributed with some separation of open spacing, such as roads and gardens. Therefore, the wooden houses neighboring the burning houses with some separation are heated by radiation and flames to elevate the temperatures, thus causing the ignition, and finally reaching a large city fire. The authors have studied the forest fire spread and are planning to start a laboratory experiment of city fire spreading. In the preliminary investigation, a numerical study is made to correlate with the laboratory experiment of city fire propagation, utilizing the three-dimensional CFD simulations. Based on the detailed experimental analysis, the authors are attempting to modify the three dimensional CFD code to predict the forest fires and city fires more precisely, taking into account the thermal heating and ignition processes. In this study, some fundamental information on the city fire propagation has been obtained, particularly to know the safe open spacing distances between the houses in the cities and also the wind speed.

scholarly journals Mathematical modeling of the initiation and spread of forest fires and their impact on buildings and structures

2020 ◽  
Vol 99 (3) ◽  
pp. 54-61
Author(s):  
V.A. Perminov ◽  
◽  
K.O. Fryanova ◽  
Keyword(s):  
Mathematical Modeling ◽  
Forest Fire ◽  
Forest Fires ◽  
Control Volume ◽  
Fire Spread ◽  
Discrete Analogue ◽  
Temperature Fields ◽  
Emergency Situations ◽  
Volume Method ◽  
Fire Spreading

Currently, methods of mathematical modeling are used to study processes in emergency situations. Forest fires are extremely complex and destructive natural phenomena which depend on availability of fuel, meteorological and other conditions. Mathematical model of forest fire is based on an analysis of known experimental data and using concept and methods from reactive media mechanics. In this paper the theoretical study of the problems of crown forest fire spread in windy condition and their thermal impact on the wooden building were carried out. The research was based on numerical solution of two-dimensional Reynolds equations. The boundary-value problem is solved numerically using the method of splitting according to physical processes. A discrete analogue for the system of equations was obtained by means of the control volume method. A study of forest fire spreading made it possible to obtain a detailed picture of the change of the component concentration of gases and temperature fields in forest fire and on the wall of building with time. It let to determine the limiting distances between forest fire and building for possibility of wooden walls ignition for different meteorology conditions, size of building and intensity of fire impact.

Fire spread in canyons

2004 ◽  
Vol 13 (3) ◽  
pp. 253 ◽  
Author(s):  
Domingos Xavier Viegas ◽  
Luis Paulo Pita
Keyword(s):  
Forest Fires ◽  
Numerical Study ◽  
Fire Spread ◽  
Laboratory Scale ◽  
Experimental Program ◽  
Small Scale ◽  
Geometrical Parameters ◽  
Fire Behaviour ◽  
Fatal Accidents ◽  
Rate Of Spread

Canyons or ridges are associated with a large number of fatal accidents produced during forest fires all over the world. A contribution to the understanding of fire behaviour in these terrain conditions is given in this paper. The basic geometrical parameters of the canyon configuration are described. An analytical model assuming elliptical growth of point ignition fires and constant values of rate of spread is proposed. A non-dimensional formulation to transfer results from analytical, numerical, laboratory or field simulations to other situations is proposed. An experimental study at laboratory scale on a special test rig is described. A wide set of canyon configurations were covered in the experimental program. In spite of the relatively small scale of the experiments they were able to put in evidence some of the main features found in fires spreading in this type of terrain. They show that in practically all cases the rate of spread of the fire front is non-constant. On the contrary, the fire has a dynamic behaviour and its properties depend not only on the canyon geometry but on the history of fire development as well. The convection induced by the fire is enhanced by terrain curvature and the fire accelerates causing the well-known blow-up that is associated with canyon fires. The rate of spread of the head fire increases continuously even in the absence of wind or any other special feature or change of boundary conditions that are sometimes invoked to justify such fire behaviour. The results of the present study confirm the predictions of a previous numerical study of the flow and fire spread in canyons that showed the important feedback effect of the fire on the atmospheric flow and how this affects fire behaviour in canyons. Results from a field experiment carried out in a canyon-shaped plot covered by tall shrubs were used to validate the laboratory scale experiments. Case studies related to fatal accidents that occurred in canyon-shaped configurations are analysed and recommendations to deal with this problem are made. It is shown that these accidents may occur even in the absence of special fuel or atmospheric conditions as they are intrinsically related to terrain configuration.

scholarly journals Forest Fire Spreading Using Free and Open-Source GIS Technologies

Geomatics ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 50-64
Author(s):  
Michele Mangiameli ◽  
Giuseppe Mussumeci ◽  
Annalisa Cappello
Keyword(s):  
Mathematical Models ◽  
Open Source ◽  
Forest Fires ◽  
Fire Spread ◽  
Ignition Point ◽  
Gis Technologies ◽  
Spread Model ◽  
Increased Risk ◽  
Fire Front ◽  
Fire Spreading

Forest fires are one of the most dangerous events, causing serious land and environmental degradation. Indeed, besides the loss of a huge quantity of plant species, the effects of fires can go far beyond: desertification, increased risk of landslides, soil erosion, death of animals, etc. For these reasons, mathematical models able to predict fire spreading are needed in order to organize and optimize the extinguishing interventions during fire emergencies. This work presents a new system to simulate and predict the movement of the fire front based on free and open source Geographic Information System (GIS) technologies and the Rothermel surface fire spread model, with the adjustments made by Albini. We describe the mathematical models used, provide an overview of the GIS design and implementation, and present the results of some simulations at Etna volcano (Sicily, Italy), characterized by high geomorphological heterogeneity, and where the native flora and fauna may be preserved and perpetuated. The results consist of raster maps representing the progress times of the fire front starting from an ignition point and as a function of the topography and wind directions. The reliability of results is strictly affected by the correct positioning of the fire ignition point, by the accuracy of the topography that describes the morphology of the territory, and by the setting of the meteorological conditions at the moment of the ignition and propagation of the fire.

scholarly journals A Deep Learning Approach to Downscale Geostationary Satellite Imagery for Decision Support in High Impact Wildfires

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 294
Author(s):  
Nicholas F. McCarthy ◽  
Ali Tohidi ◽  
Yawar Aziz ◽  
Matt Dennie ◽  
Mario Miguel Valero ◽  
...  
Keyword(s):  
Deep Learning ◽  
Decision Support ◽  
Real Time ◽  
Forest Fires ◽  
Wildland Fire ◽  
Fire Spread ◽  
Low Earth Orbit ◽  
Practical Implementation ◽  
Spatiotemporal Resolution ◽  
Active Fire

Scarcity in wildland fire progression data as well as considerable uncertainties in forecasts demand improved methods to monitor fire spread in real time. However, there exists at present no scalable solution to acquire consistent information about active forest fires that is both spatially and temporally explicit. To overcome this limitation, we propose a statistical downscaling scheme based on deep learning that leverages multi-source Remote Sensing (RS) data. Our system relies on a U-Net Convolutional Neural Network (CNN) to downscale Geostationary (GEO) satellite multispectral imagery and continuously monitor active fire progression with a spatial resolution similar to Low Earth Orbit (LEO) sensors. In order to achieve this, the model trains on LEO RS products, land use information, vegetation properties, and terrain data. The practical implementation has been optimized to use cloud compute clusters, software containers and multi-step parallel pipelines in order to facilitate real time operational deployment. The performance of the model was validated in five wildfires selected from among the most destructive that occurred in California in 2017 and 2018. These results demonstrate the effectiveness of the proposed methodology in monitoring fire progression with high spatiotemporal resolution, which can be instrumental for decision support during the first hours of wildfires that may quickly become large and dangerous. Additionally, the proposed methodology can be leveraged to collect detailed quantitative data about real-scale wildfire behaviour, thus supporting the development and validation of fire spread models.

Fire spreading experiments on heterogeneous fuel beds. Applications of percolation theory

2000 ◽  
Vol 30 (8) ◽  
pp. 1318-1328 ◽  
Author(s):  
Jean Nahmias ◽  
Hervé Téphany ◽  
José Duarte ◽  
Sophie Letaconnoux
Keyword(s):  
Experimental Work ◽  
Percolation Theory ◽  
Dynamic Behaviour ◽  
Fire Spread ◽  
Directed Percolation ◽  
Final State ◽  
Critical Thresholds ◽  
Scale Models ◽  
Different Types ◽  
Fire Spreading

In the experimental work presented here, fire spread was studied through various laboratory and full-scale models containing different types of combustible and noncombustible materials. We have examined the dynamic behaviour of the flame front and the final state (after extinction) on randomly created heterogeneous zones, both with and without wind. The principal conclusion is that critical thresholds exist, for the ratio between combustible and noncombustible parts, at the transition between nonpropagation and propagation of the fire. This result is common to all types of spreading (with or without wind). The values of the critical thresholds in the nonwind-driven experiments are those of the percolation theory. The critical exponent, obtained for wind-driven experiments, is in accordance with current values suggested by the directed percolation approach.

scholarly journals Fractal properties of forest fires in Amazonia as a basis for modelling pan-tropical burnt area

2014 ◽  
Vol 11 (6) ◽  
pp. 1449-1459 ◽  
Author(s):  
I. N. Fletcher ◽  
L. E. O. C. Aragão ◽  
A. Lima ◽  
Y. Shimabukuro ◽  
P. Friedlingstein
Keyword(s):  
Forest Fires ◽  
Large Scale ◽  
Fire Spread ◽  
Small Scale ◽  
Burnt Area ◽  
Active Fire ◽  
Fractal Properties ◽  
Dynamic Global Vegetation Models ◽  
Vegetation Models ◽  
Global Vegetation

Abstract. Current methods for modelling burnt area in dynamic global vegetation models (DGVMs) involve complex fire spread calculations, which rely on many inputs, including fuel characteristics, wind speed and countless parameters. They are therefore susceptible to large uncertainties through error propagation, but undeniably useful for modelling specific, small-scale burns. Using observed fractal distributions of fire scars in Brazilian Amazonia in 2005, we propose an alternative burnt area model for tropical forests, with fire counts as sole input and few parameters. This model is intended for predicting large-scale burnt area rather than looking at individual fire events. A simple parameterization of a tapered fractal distribution is calibrated at multiple spatial resolutions using a satellite-derived burnt area map. The model is capable of accurately reproducing the total area burnt (16 387 km2) and its spatial distribution. When tested pan-tropically using the MODIS MCD14ML active fire product, the model accurately predicts temporal and spatial fire trends, but the magnitude of the differences between these estimates and the GFED3.1 burnt area products varies per continent.

scholarly journals Modelling Forest Fires Using Complex Networks

2021 ◽  
Vol 26 (4) ◽  
pp. 68
Author(s):  
Sara Perestrelo ◽  
Maria C. Grácio ◽  
Nuno A. Ribeiro ◽  
Luís M. Lopes
Keyword(s):  
Forest Fires ◽  
Previous Knowledge ◽  
Time Duration ◽  
Spreading Process ◽  
Multilayer Network ◽  
Major Threat ◽  
Rate Of Spread ◽  
Spreading Dynamics ◽  
Fire Spreading ◽  
Network Of Networks

Forest fires have been a major threat to the environment throughout history. In order to mitigate its consequences, we present, in a first of a series of works, a mathematical model with the purpose of predicting fire spreading in a given land portion divided into patches, considering the area and the rate of spread of each patch as inputs. The rate of spread can be estimated from previous knowledge on fuel availability, weather and terrain conditions. We compute the time duration of the spreading process in a land patch in order to construct and parametrize a landscape network, using cellular automata simulations. We use the multilayer network model to propose a network of networks at the landscape scale, where the nodes are the local patches, each with their own spreading dynamics. We compute some respective network measures and aim, in further work, for the establishment of a fire-break structure according to increasing accuracy simulation results.

scholarly journals A Comparative Analytical Study of Some External Finishing (Cladding) Material in Terms of Their Ability to Spread Fire in Multi-story Building Facades in Iraq

2020 ◽  
Vol 10 (5) ◽  
pp. 647-654
Author(s):  
Ahmed A. Alfakhry
Keyword(s):  
Computer Modeling ◽  
Analytical Study ◽  
Raw Materials ◽  
Fire Spread ◽  
Building Facades ◽  
The Difference ◽  
Fire Spreading ◽  
Story Building ◽  
Cladding Material ◽  
Main Factor

The traditional building in Iraq characterised by the using of a certain number of finishing's in external façades like cement plastering, limestone and perforated yellow brick because the raw materials of manufacturing are available locally. Fire spread through the facades is widely recognized as one of the fastest pathways of fire spreading in the buildings, so the appropriate choose of highly performance finishing material against fire will be potentially the main factor in controlling the fire and suppressed it. This study uses computer modeling and fire simulation technology of Pyrosim, FDS and smoke view to compare the difference between the performance of some traditional finishing materials like cement plastering, limestone and perforated yellow brick with the ACPs and their speed to transfer fire from floor to floor if used in multi storey buildings. The study highlighted that traditional finishing materials are more efficient than modern cladding materials and that the performance of ACP-PE is the worst among the materials examined by this study. Moreover, the cement plastering is the worst among the traditional local finishing materials.

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