Field-Scale Physical Modelling of Grassfire Propagation on Sloped Terrain under Low-Speed Driving Wind
Abstract
:1. Introduction
2. Simulation Methodology, Parameters, and Variables
3. Postprocessing Methodology
3.1. Isochrones, Pyrolysis Width, and Fire Propagation
3.2. Visualisation of Plume Contours
3.3. Determination of Flame Length
3.4. Determination of Heat Flux
4. Results and Discussion
4.1. Progression of Isochrones and Pyrolysis Width
4.2. Heat Release Rate (HRR) and Fire Intensity
4.3. Fire Front Locations, Dynamic RoS, and RoS Calculations
4.3.1. Fire Front Locations
4.3.2. Dynamic RoS
4.3.3. Averaged RoS
4.3.4. Relative
4.3.5. Fire Intensity Q as a Function of RoS
4.4. Plume and Flame Dynamics at Lower Wind Velocities
4.5. Mode of Fire Propagation
4.6. Flame Length
4.7. Heat Fluxes
5. Summary and Conclusions
Supplementary Materials
Author Contributions
Funding
Data Availability Statement
Conflicts of Interest
Abbreviations
AS3959 | Australian Standard 3959 |
BF | boundary fuel |
CFD | computational fluid dynamics |
CSIRO | Commonwealth Scientific and Industrial Research Organization |
FDS | Fire Dynamic Simulator |
FMC | fuel moisture content |
FE | fuel element |
GFDI | Grassland Fire Danger Index Meter |
heat release rate | |
LES | large eddy simulation |
RoS | rate of spread |
SEM | synthetic eddy methodology |
WFDS | Wildland–Urban Interface Fire Dynamics Simulator |
References
- Innocent, J.; Moinuddin, K.; Sutherland, D.; Khan, N. Physics-based simulations of grassfire propagation on sloped terrain at field-scale: Motivations, model reliability, rate of spread and intensity. Int. J. Wildland Fire 2022, 32, 496–512. [Google Scholar] [CrossRef]
- Innocent, J.; Sutherland, D.; Khan, N. Moinuddin, Physics-based simulations of grassfire propagation on sloped terrain at field-scale: Flame dynamics, mode of fire propagation and the heat fluxes. Int. J. Wildland Fire 2022, 32, 513–530. [Google Scholar] [CrossRef]
- Mell, W.; Jenkins, M.; Gould, J.S.; Cheney, N.P. A physics-based approach to modelling grassland fires. Int. J. Wildland Fire 2007, 16, 1–22. [Google Scholar]
- McGrattan, K.B.; Forney, G.P.; Hostikka, S.; McDermott, R.; Weinschenk, C. Fire Dynamics Simulator, User’s Guide, 6th ed.; Original Version 2013, Revised Version 6.3.2 in 2015; NIST Special Publication: Gaithersburg, MD, USA, 2013; p. 1019. [Google Scholar] [CrossRef]
- Morvan, D.; Accary, G.; Meradji, S.; Frangieh, N.; Bessonov, O. A 3D physical model to study the behavior of vegetation fires at laboratory scale. Fire Saf. J. 2018, 101, 39–52. [Google Scholar]
- Sharples, J.J. Risk Implications of Dynamic Fire Propagation, A Case Study of the Ginninderry Region; Preliminary Report, June 2017; Ginninderra Falls Association: New South Wales, Australia, 2017. [Google Scholar]
- Hilton, J.E.; Miller, C.; Sharples, J.J.; Sullivan, A.L. Curvature effects in the dynamic propagation of wildfires. Int. J. Wildland Fire 2016, 25, 1238–1251. [Google Scholar]
- Hoffman, C.M.; Canfield, J.; Linn, R.R.; Mell, W.; Sieg, C.H.; Pimont, F.; Ziegler, J. Evaluating Crown Fire Rate of Spread Predictions from Physics-Based Models. Fire Technol. 2015, 52, 221–237. [Google Scholar]
- Moinuddin, K.; Khan, N.; Sutherland, D. Numerical study on effect of relative humidity (and fuel moisture) on modes of grassfire propagation. Fire Saf. J. 2021, 125, 103422. [Google Scholar]
- Sutherland, D.; Sharples, J.J.; Moinuddin, K.A.M. The effect of ignition protocol on grassfire development. Int. J. Wildland Fire 2020, 29, 70. [Google Scholar] [CrossRef]
- McArthur, A.G. Weather and Grassland Fire Behaviour. In Forestry and Timber Bureau; Department of National Development, Commonwealth: Canberra, Australia, 1966. [Google Scholar]
- McArthur, A.G. Fire Behaviour in Eucalypt Forests. In Forestry and Timber Bureau; Department of National Development, Commonwealth: Canberra, Australia, 1967. [Google Scholar]
- Cheney, N.P.; Gould, J.S.; Catchpole, W.R. Prediction of Fire Spread in Grasslands. Int. J. Wildland Fire 1998, 8, 1–13. [Google Scholar] [CrossRef]
- Noble, I.R.; Gill, A.; Barry, G. McArthur’s fire-danger meters expressed as equations. Aust. J. Ecol. 1980, 5, 201–203. [Google Scholar]
- Moinuddin, K.; Sutherland, D.; Mell, W. Simulation study of grass fire using a physics-based model: Striving towards numerical rigour and the effect of grass height on the rate-of-spread. Int. J. Wildland Fire 2018, 27, 800–814. [Google Scholar] [CrossRef]
- Rothermel, R.C. A Mathematical Model for Predicting Fire Spread in Wildland Fuels; General Technical Report INT-115; Intermountain Forest and Range, USDA Forest Service: Ogden, UT, USA, 1972. [Google Scholar]
- Andrews, P.L. The Rothermel Surface Fire Spread Model and Associated Developments: A Comprehensive Explanation; General Techncial Report RMRS-GTR-371; United States Department of Agriculture, Forest Service: Washington, DC, USA, 2018. [Google Scholar]
- Wilson, R. Reexamination of Rothermels Fire Spread Equations in No-Wind and No-Slope Conditions; Research Paper INT-434; United States Department of Agriculture, Forest Service: Washington, DC, USA, 1990. [Google Scholar]
- Weise, D.; Biging, G. A Qualitative Comparison of Fire spread model incorporating wind and slope effects. For. Sci. 1997, 43, 170–180. [Google Scholar]
- Cruz, M.; Alexander, M.E.; Kilinc, M. Wildfire Rates of Spread in Grasslands under Critical Burning Conditions. Fire 2022, 5, 55. [Google Scholar] [CrossRef]
- Bishe, E.M.; Afshin, H.; Farhanieh, B. Modified Quasi-Physcial Grassland Fire Spread Model: Sensitivity Analysis. Sustainability 2023, 15, 13639. [Google Scholar] [CrossRef]
- Cheney, N.; Gould, J.; Catchpole, W. The Influence of Fuel, Weather and Fire Shape Variables on Fire-Spread in Grasslands. Int. J. Wildland Fire 1993, 3, 31–44. [Google Scholar] [CrossRef]
- Byram, G. Combustion of Forest Fuels. In Forest Fire: Control and Use; Davis, K.P., Ed.; McGraw-Hill: New York, NY, USA, 1959; pp. 61–89. [Google Scholar]
- Mell, W.; Simeoni, A.; Morvan, D.; Hiers, J.K.; Skowronski, N.; Hadden, R.M. Clarifying the meaning of mantras in wildland fire behaviour modelling: Reply to Cruz et al. (2017). Int. J. Wildland Fire 2018, 27, 770–775. [Google Scholar] [CrossRef]
- Morvan, D.; Frangieh, N. Wildland fires behaviour: Wind effect versus Byram’s convective number and consequences upon the regime. Int. J. Wildland Fire 2018, 27, 636. [Google Scholar] [CrossRef]
- Dupuy, J.-L.; Maréchal, J. Slope effect on laboratory fire spread: Contribution of radiation and convection to fuel bed preheating. Int. J. Wildland Fire 2011, 20, 289–307. [Google Scholar] [CrossRef]
- Alexander, M.E.; Cruz, M.G. Interdependencies between flame length and fireline intensity in predicting crown fire initiation and crown scorch height. Int. J. Wildland Fire 2012, 21, 95–113, Supplementary Erratum in Int. J. Wildland Fire 2021, 30, 70. [Google Scholar] [CrossRef]
- Anderson, H.; Brackebusch, A.P.; Mutch, R.W.; Rothermel, R.C. Mechanisms of Fire Spread Research Progress Report No. 2; Research Paper INT-28; US Forest Service: Washington, DC, USA, 1966. [Google Scholar]
- Jarrin, N.; Benhamadouche, S.; Laurence, D.; Prosser, R. A synthetic-eddy-method for generating inflow conditions for large-eddy simulations. Int. J. Heat Fluid Flow 2006, 27, 585–593. [Google Scholar] [CrossRef]
- Sánchez-Monroy, X.; Mell, W.; Torres-Arenas, J.; Butler, B.W. Fire spread upslope: Numerical simulation of laboratory experiments. Fire Saf. J. 2019, 108, 102844. [Google Scholar] [CrossRef]
- AS 3959-2018; Construction of Buildings in Bushfire Prone Area. Australian Standard: Sydney, Australia, 2018.
- Overholt, K.J.; Cabrera, J.; Kurzawski, A.; Koopersmith, M.; Ezekoye, O.A. Characterization of Fuel Properties and Fire Spread Rates for Little Bluestem Grass. Fire Technol. 2014, 50, 9–38. [Google Scholar] [CrossRef]
- Abu Bakar, A. Characterization of Fire Properties for Coupled Pyrolysis and Combustion Simulation and Their Optimised Use. Ph.D. Thesis, Victoria University, Melbourne, Australia, 2015. [Google Scholar]
- Morvan, D.; Dupuy, J.L. Modeling the propagation of a wildfire through a Mediterranean shrub using a multiphase formulation. Combust. Flame 2004, 138, 199–210. [Google Scholar] [CrossRef]
- Cheney, N.P.; Gould, J.S. Fire Growth in Grassland Fuels. Int. J. Wildland Fire 1995, 5, 237. [Google Scholar] [CrossRef]
- Davis, T.; Sigmon, K. MATLAB Premier, 7th ed.; Chapman & Hall/CRC: Boca Raton, FL, USA, 2005; Available online: www.dbeBooks.com (accessed on 1 June 2017).
- Cobian-Iñiguez, J.; Aminfar, A.; Weise, D.R.; Princevac, M. On the Use of Semi-empirical Flame Models for Spreading Chaparral Crown Fire. Front. Mech. Eng. 2019, 5, 50. [Google Scholar] [CrossRef]
- Dupuy, J.L.; Mare’chal, J.; Portier, D.; Valette, J.-C. The effects of slope and fuel bed width on laboratory fire behaviour. Int. J. Wildland Fire 2011, 20, 272–288. [Google Scholar] [CrossRef]
- Tihay, V.; Morandini, F.; Santoni, P.-A.; Perez-Ramirez, Y.; Barboni, T. Combustion of forest litters under slope conditions: Burning rate, heat release rate, convective and radiant fractions for different loads. Combust. Flame 2014, 161, 3237–3248. [Google Scholar] [CrossRef]
- Beck, J.A. Equations For The Forest Fire Behaviour Tables For Western Australia. CALM Sci. 1995, 1, 325–348. [Google Scholar]
- Pimont, F.; Dupuy, J.L.; Linn, R.R. Coupled slope and wind effects on fire spread with influences of fire size: A numerical study using FIRETEC. Int. J. Wildland Fire 2012, 21, 828–842. [Google Scholar] [CrossRef]
- Sullivan, A.L.; Sharples, J.J.; Matthews, S.; Plucinski, M.P. A downslope fire spread correction factor based on landscape-scale fire behaviour. Environ. Model. Softw. 2014, 62, 153–163. [Google Scholar] [CrossRef]
- Mendes-Lopes, J.M.C.; Ventura, J.M.P.; Amaral, J.M.P. Flame characteristics, temperature–time curves, and rate of spread in fires propagating in a bed of Pinus pinaster needles. Int. J. Wildland Fire 2003, 12, 67. [Google Scholar] [CrossRef]
- Dold, J.W.; Zinoviev, A. Fire eruption through intensity and spread rate interaction mediated by flow attachment. Combust. Theory Model. 2009, 13, 763–793. [Google Scholar] [CrossRef]
Slope Angle (Degree) | Domain Size: 360 × 120 × 60 M | Domain Size: 480 × 180 × 80 M | |||
---|---|---|---|---|---|
Burnable grass plot 80 × 40 m | |||||
Wind velocity | 0.1 m/s, Set 1 | 1 m/s, Set 2 | 1 m/s, Set 3 | 1 m/s, Set 4 | |
Fuel parameters | Original | Original | Original | Changed | |
–10° | √ | √ | |||
0° | √ | √ | √ | √ | |
+5° | √ | √ | √ | √ | |
+10° | √ | √ | √ | √ | |
+15° | √ | √ | √ | √ | |
+20° | √ | √ | √ | √ | |
+25° | √ | √ | √ | √ | |
+30° | √ | √ | √ | √ |
Input Parameters | Values Used | Source and Reason | |
---|---|---|---|
Sets 1–3 | Set 4 | ||
Fuel—grass | Grass type: kerosene (Eriachne burkittii) [3,15,22] | ||
Heat of combustion | 16,400 kJ/kg | 16,400 kJ/kg | Bluestem grass [32] |
Soot yield | 0.008 g/g | 0.008 g/g | White pine (Australian Radiata pine) [33] |
Vegetation drag coefficient | 0.125 | assuming vegetation elements are spherical [34] | |
Vegetation load | 0.85 kg/m2 | 0.31 kg/m2 | |
Vegetation height | 0.6 m | 0.6 m | |
Vegetation moisture content | 0.065 | 0.024 | Experimental, Cheney et al. [3,22,35] |
Surface area-to-volume ratio of vegetation | 9770/m | 9770/m | Experimental, Cheney et al. [3,22,35] |
Vegetation char fraction | 0.17 | 0.17 | Average of Cheney and Gould [22] and Bluestem grass [32] |
Vegetation element density | 440 kg/m3 | 160 kg/m3 | Australian Radiata pine (Abu Bakar 2015) [33], hay or straw density |
Ambient temperature | 32 °C | 50 °C | Experimental ([22]), Cheney and Gould [24] |
Relative humidity | 40% | 10% | Experimental [3,22,35] |
Emissivity | 0.99 | 0.99 | Cheney and Gould (1995), [22] |
Pyrolysis temperature | 400–500 K | 400–500 K | Morvan et al. [34] |
Degree of curing | 100% | 100% | Assuming vegetation 100% cured |
Heat of pyrolysis | 200 kJ/kg | 200 kJ/kg | White pine (Australian Radiata pine) [33] |
RoS | Pattern | 0.1 m/s, Set 1 | 1 m/s, Set 3, Original Fuel | 1 m/s (Set 4), “Lighter & Drier” Fuel | |||
---|---|---|---|---|---|---|---|
Equation | R2 | Equation | R2 | Equation | R2 | ||
Dynamic RoS, average | Exponential | 0.0752e0.054x | 0.998 | 0.1263e0.0411x | 0.978 | 0.235e0.034x | 0.984 |
Quasi-steady RoS | Exponential | 0.0711e0.0528x | 0.990 | 0.1179e0.0405x | 0.997 | 0.2025e0.0404x | 0.992 |
Slope Angle | Driving Wind Velocity | ||
---|---|---|---|
0.1 m/s | 1 m/s | ||
Set 1 | Set 3 | Set 4 | |
+5° to +15° | 87% | 60% | 60% |
+10° to +20° | 87% | 55% | 53% |
+15° to +25° | 55% | 45% | 50% |
+20° to +30° | 59% | 45% | 44% |
Pattern | 0.1 m/s, Set 1 | 1 m/s, Set 3 | 1 m/s, Set 4 | |||
---|---|---|---|---|---|---|
Equation | R2 | Equation | R2 | Equation | R2 | |
Exponential | 0.6326e0.0528x | 0.990 | 0.6675e0.0405x | 0.997 | 0.6693e0.0404x | 0.992 |
Polynomial | 0.0012x2 + 0.0496x + 0.4224 | 0.995 | 0.0007x2 + 0.0309x + 0.6253 | 0.999 | 0.0005x2 + 0.0383x + 0.582 | 0.998 |
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content. |
© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
Share and Cite
Innocent, J.; Sutherland, D.; Moinuddin, K. Field-Scale Physical Modelling of Grassfire Propagation on Sloped Terrain under Low-Speed Driving Wind. Fire 2023, 6, 406. https://doi.org/10.3390/fire6100406
Innocent J, Sutherland D, Moinuddin K. Field-Scale Physical Modelling of Grassfire Propagation on Sloped Terrain under Low-Speed Driving Wind. Fire. 2023; 6(10):406. https://doi.org/10.3390/fire6100406
Chicago/Turabian StyleInnocent, Jasmine, Duncan Sutherland, and Khalid Moinuddin. 2023. "Field-Scale Physical Modelling of Grassfire Propagation on Sloped Terrain under Low-Speed Driving Wind" Fire 6, no. 10: 406. https://doi.org/10.3390/fire6100406