The effects of slope and fuel bed width on laboratory fire behaviour

2011 ◽  
Vol 20 (2) ◽  
pp. 272 ◽  
Author(s):  
J.-L. Dupuy ◽  
J. Maréchal ◽  
D. Portier ◽  
J.-C. Valette
Keyword(s):  
Fuel Consumption ◽  
Residence Time ◽  
Line Intensity ◽  
Pinus Halepensis ◽  
Slope Angle ◽  
Fire Behaviour ◽  
Qualitative Behaviour ◽  
Rate Of Spread ◽  
Operational Models

A set of 109 laboratory fires in Pinus halepensis fuel beds (1 kg m–2) was used to test the effects of slope (0°, 10°, 20°, 30°) and fuel bed width (1, 2, 3 m) on fire behaviour variables such as rate of spread, fuel consumption, flame residence time, temperatures and flame geometry. The qualitative behaviour of the fires is also reported. The 20° and 30° upslope fires are pointed in shape and fire whirls moving along the fire flanks in the direction of the fire head are systematically observed in 30° upslope fires. Flame residence time increases with increasing slope angle, and both slope angle and fuel bed width affect rate of spread. The slope effects observed in 10° and 20° slope angles and in the narrowest fuel beds (1 and 2 m) are similar to those predicted by operational models. However, the observed slope effect at the 30° slope angle is underestimated by these models, in particular in 3 m-wide fuel beds. Flame temperatures correlate closely with dimensionless height and flame lengths correlate closely with fire line intensity. Mechanisms that could explain the different effects observed are suggested and discussed.

Slope and Fuel Load Effects on Fire Behavior: Laboratory Experiments in Pine Needles Fuel Beds

1995 ◽  
Vol 5 (3) ◽  
pp. 153 ◽  
Author(s):  
JL Dupuy
Keyword(s):  
Laboratory Experiments ◽  
Pinus Halepensis ◽  
Fire Behavior ◽  
Fuel Load ◽  
Fire Behaviour ◽  
Rate Of Spread ◽  
Load Effects ◽  
Heat Transfers ◽  
Different Levels ◽  
Fire Experiments

Laboratory fire experiments were conducted in both Pinus pinaster and Pinus halepensis litters in order to investigate the effect of slope on fire behaviour for different levels of fuel load. Simulated slopes ranged between -30 degrees and +30 degrees. The results are reported in terms of rate of spread and rate of mass loss when observed fire was quasi-steady. Upslope fires were observed, on the present devices, to be unsteady, and their flame to be three-dimensionnal, when slope and fuel load exceeded certain limits. The heat transfers involved in the explanation of the observed behaviours are discussed, especially on the base of the quite different results obtained in the two tested fuel. beds.

Coupled slope and wind effects on fire spread with influences of fire size: a numerical study using FIRETEC

2012 ◽  
Vol 21 (7) ◽  
pp. 828 ◽  
Author(s):  
F. Pimont ◽  
J.-L. Dupuy ◽  
R. R. Linn
Keyword(s):  
Blow Up ◽  
Numerical Study ◽  
Fire Spread ◽  
Combined Effects ◽  
Fire Behaviour ◽  
Factors Affecting ◽  
Wind Speeds ◽  
Topographic Slope ◽  
Rate Of Spread ◽  
Operational Models

Wind and slope are commonly accepted to be major environmental factors affecting the manner in which wildfires propagate. Fire-line width has been observed as having a significant effect on fire behaviour in some experimental fires. Most wildfire behaviour models and fire behaviour prediction systems take wind and slope effects into account when determining the rate of spread, but do not take into account the influence of fire width on the coupled effects of slope and wind. In the present study, the effect of topographic slope on rate of spread under weak (1 m s–1), moderate (5 m s–1) and strong (12 m s–1) wind speeds is investigated for two different initial fire widths (20 and 50 m) in a typical Mediterranean garrigue, using the coupled atmosphere–fire HIGRAD-FIRETEC model. The results show non-trivial combined effects and suggest a strong effect of fire width under low-wind conditions, especially for steep slopes. Simulated spread rates were compared with predictions of existing models of operational systems and a reasonable agreement was found. Additional exploratory simulations of fire behaviour in small canyons are provided. These simulations show how combined effects of wind, slope and fire-front size can induce different fire behaviours that operational models could fail to predict and provide insight that could be valuable for analysis of blow-up fires. These preliminary results also suggest that 3D physically based models could be used in the future to investigate how operational models can include non-local effects of fire propagation.

Quasi-Periodic Control Technique for Minimizing Fuel Consumption During Record Vehicle Competition

2013 ◽  
Vol 60 (2) ◽  
pp. 185-197 ◽  
Author(s):  
Paweł Sulikowski ◽  
Ryszard Maronski
Keyword(s):  
Fuel Consumption ◽  
Optimal Control Theory ◽  
Slope Angle ◽  
Control Technique ◽  
Decision Variables ◽  
Aeronautical Engineering ◽  
The One ◽  
Optimal Driving ◽  
The Given ◽  
Engine Power

The problem of the optimal driving technique during the fuel economy competition is reconsidered. The vehicle is regarded as a particle moving on a trace with a variable slope angle. The fuel consumption is minimized as the vehicle covers the given distance in a given time. It is assumed that the run consists of two recurrent phases: acceleration with a full available engine power and coasting down with the engine turned off. The most fuel-efficient technique for shifting gears during acceleration is found. The decision variables are: the vehicle velocities at which the gears should be shifted, on the one hand, and the vehicle velocities when the engine should be turned on and off, on the other hand. For the data of students’ vehicle representing the Faculty of Power and Aeronautical Engineering it has been found that such driving strategy is more effective in comparison with a constant speed strategy with the engine partly throttled, as well as a strategy resulting from optimal control theory when the engine is still active.

scholarly journals Fire Behaviour Observation in Shrublands in Nova Scotia, Canada and Assessment of Aids to Operational Fire Behaviour Prediction

Fire ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 34
Author(s):  
Anne-Claude Pepin ◽  
Mike Wotton
Keyword(s):  
Nova Scotia ◽  
Moisture Content ◽  
Bulk Density ◽  
Prediction Models ◽  
Seasonal Effect ◽  
Fuel Type ◽  
Fire Behaviour ◽  
Fire Weather Index ◽  
Rate Of Spread ◽  
Wide Range

Parks Canada, in collaboration with Nova Scotia Lands and Forests and Natural Resources Canada, documented shrub fire behaviour in multiple plots burned over two periods: a spring period in June 2014 and a summer period in July 2017. The study area, located within Cape Breton Highlands National Park, comprised fifteen burn units (20 m by 20 m in size). Each unit was ignited by line ignition and burned under a wide range of conditions. Pre-burn fuel characteristics were measured across the site and used to estimate pre-fire fuel load and post-fire fuel consumption. This fuel complex was similar to many flammable shrub types around the world, results show that this shrub fuel type had high elevated fuel loads (3.17 ± 0.84 kg/m2) composed of exposed live and dead stunted black spruce as well as ericaceous shrubs, mainly Kalmia angustifolia (evergreen) and Rhodora canadensis (deciduous). Data show that the dead moisture content in this fuel complex is systematically lower than expected from the traditional relationship between FFMC and moisture content in the Canadian Fire Weather Index System but was statistically correlated with Equilibrium Moisture Content. A significant inverse relationship between bulk density and fire rate of spread was observed as well as a clear seasonal effect between the spring burns and the summer burns, which is likely attributable to the increase in bulk density in the summer. Unlike most shrub research, wind and dead moisture content did not have a statistically significant association with fire spread rates. However, we believe this to be due to noise in wind data and small dataset. Rate of spread as high as 14 m/min and flame lengths over 4 m were recorded under Initial Spread Index values of 6.4 and relative humidity of 54%. A comparison with a number of well-known shrubland spread rate prediction models was made. An aid to operational fire prediction behaviour is proposed, using a fuel type from the Canadian Fire Prediction System (O-1b) and a modified estimate of fuel moisture of the elevated fuel in the fuel complex.

scholarly journals Flammability of litter sampled according to two different methods: comparison of results in laboratory experiments

2014 ◽  
Vol 23 (8) ◽  
pp. 1061 ◽  
Author(s):  
Anne Ganteaume ◽  
Marielle Jappiot ◽  
Thomas Curt ◽  
Corinne Lampin ◽  
Laurent Borgniet
Keyword(s):  
Laboratory Experiments ◽  
Sampling Method ◽  
Future Research ◽  
Vegetation Types ◽  
Fire Behaviour ◽  
Rate Of Spread ◽  
Litter Flammability ◽  
Different Types ◽  
Flammability Parameters ◽  
Density Rate

In the laboratory, different types of litter samples (constructed v. intact) can be used in flammability experiments but the sampling method of these litters could affect litter flammability results. To assess this effect, samples of litters were collected in South-eastern France, according to two different methods previously used in other studies, one keeping intact the structure of the litter layers (non-constructed litter) and the other requiring the construction of the litter, using mainly the surface litter layer (constructed litter). The comparison of flammability results showed that the sampling method had a significant effect on litter bulk-density, rate of spread and rate of consumption, intact litter being more flammable than reconstructed litter that was artificially compacted. The type of vegetation had a significant effect on litter depth, ignitability, sustainability, consumability and combustibility (except on rate of spread) and the litter composition could explain in part this fire behaviour. The effect of the construction of litters on flammability parameters and its magnitude also differed according to vegetation types. Intact litter structure appeared to be an important driver of its flammability, especially of combustibility and consumability. The assessment of these flammability components will differ when using constructed litter samples instead of intact litter samples, especially according to vegetation types. Future research on litter flammability should take into account the bias due to the litter sampling method when the litter is constructed.

Got to burn to learn: the effect of fuel load on grassland fire behaviour and its management implications

2018 ◽  
Vol 27 (11) ◽  
pp. 727 ◽  
Author(s):  
Miguel G. Cruz ◽  
Andrew L. Sullivan ◽  
James S. Gould ◽  
Richard J. Hurley ◽  
Matt P. Plucinski
Keyword(s):  
Fire Spread ◽  
Flame Height ◽  
Fuel Load ◽  
Limiting Factor ◽  
Fire Behaviour ◽  
Load Effect ◽  
Fire Propagation ◽  
Rate Of Spread ◽  
Eastern Australia ◽  
Modelling Assumptions

The effect of grass fuel load on fire behaviour and fire danger has been a contentious issue for some time in Australia. Existing operational models have placed different emphases on the effect of fuel load on model outputs, which has created uncertainty in the operational assessment of fire potential and has led to end-user and public distrust of model outcomes. A field-based experimental burning program was conducted to quantify the effect of fuel load on headfire rate of spread and other fire behaviour characteristics in grasslands. A total of 58 experimental fires conducted at six sites across eastern Australia were analysed. We found an inverse relationship between fuel load and the rate of spread in grasslands, which is contrary to current, untested, modelling assumptions. This result is valid for grasslands where fuel load is not a limiting factor for fire propagation. We discuss the reasons for this effect and model it to produce a fuel load effect function that can be applied to operational grassfire spread models used in Australia. We also analyse the effect of fuel load on flame characteristics and develop a model for flame height as a function of rate of fire spread and fuel load.

HISTORY OF A SMALL CROWN FIRE

1964 ◽  
Vol 40 (2) ◽  
pp. 202-209 ◽  
Author(s):  
C. E. Van Wagner
Keyword(s):  
Red Pine ◽  
Energy Output ◽  
Crown Fire ◽  
Fire Behaviour ◽  
Pine Plantation ◽  
Rate Of Spread ◽  
Fast Spreading ◽  
History Of ◽  
Slow Moving ◽  
Extreme Fire

An 80-foot-square plot in a red pine plantation was burned at extreme fire danger as part of a study of fire behaviour and effect. When the wind reversed its direction, the original slow-moving back-fire changed within a few minutes to a fast-spreading crown fire. The transition from surface to crowns is described in terms of rate of spread, fuel weight consumed and energy output.

scholarly journals WATI: Warning of Traffic Incidents for Fuel Saving

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
V. Corcoba Magaña ◽  
M. Muñoz-Organero
Keyword(s):  
Fuel Consumption ◽  
Heavy Traffic ◽  
Slope Angle ◽  
Resistance Coefficient ◽  
Accelerator Pedal ◽  
Traffic Incidents ◽  
The Road ◽  
Adverse Weather ◽  
On The Road ◽  
The Impact

Traffic incidents (heavy traffic, adverse weather conditions, and traffic accidents) cause an increase in the frequency and intensity of the acceleration and deceleration. The result is a very significant increase in fuel consumption. In this paper, we propose a solution to reduce the impact of such events on energy consumption. The solution detects the traffic incidents based on measured telemetry data from vehicles and the different driver profiles. The proposal takes into account the rolling resistance coefficient, the road slope angle, and the vehicles speeds, from vehicles which are on the scene of the traffic incident, in order to estimate the optimal deceleration profile. Adapted advice and feedback are provided to the drivers in order to appropriately and timely release the accelerator pedal. The expert system is implemented on Android mobile devices and has been validated using a dataset of 150 tests using 15 different drivers. The main contribution of this paper is the proposal of a system to detect traffic incidents and provide an optimal deceleration pattern for the driver to follow without requiring sensors on the road. The results show an improvement on the fuel consumption of up to 13.47%.

Behaviour and effects of prescribed fire in masticated fuelbeds

2011 ◽  
Vol 20 (8) ◽  
pp. 932 ◽  
Author(s):  
Eric E. Knapp ◽  
J. Morgan Varner ◽  
Matt D. Busse ◽  
Carl N. Skinner ◽  
Carol J. Shestak
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Tree Mortality ◽  
Fire Hazard ◽  
Weather Conditions ◽  
Flame Length ◽  
Fire Behaviour ◽  
Prescribed Burns ◽  
Rate Of Spread ◽  
Fuel Models

Mechanical mastication converts shrub and small tree fuels into surface fuels, and this method is being widely used as a treatment to reduce fire hazard. The compactness of these fuelbeds is thought to moderate fire behaviour, but whether standard fuel models can accurately predict fire behaviour and effects is poorly understood. Prescribed burns were conducted in young ponderosa pine (Pinus ponderosa Laws.) forests at two sites in northern California where the midstorey layer dominated by shrubs had been masticated. Surface fuels were raked from the base of a subset of trees before burning. Rate of spread and flame length were estimated for both backing and heading fires, soil heating measured with thermocouples and tree fire injury recorded. Standard fuel models often over-predicted rate of spread or under-predicted flame length. Custom models generally provided a better balance between the slow rates of spread and moderate flame lengths observed in prescribed burns. Post-fire tree mortality was most strongly associated with crown scorch and tree size; raking fuels from the base of trees did not improve survival. Under severe fire weather conditions, fire behaviour and effect models as well as observations from wildfires suggest that mastication may be more effective for moderating fire behaviour than reducing residual tree mortality. Treating masticated fuels with prescribed burns could potentially improve the resilience of stands to wildfire.

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