@article {bnh-7343, title = {Effect of weather forecast errors on fire growth model projections}, journal = {International Journal of Wildland Fire}, year = {2020}, month = {08/2020}, abstract = {

Fire management agencies use fire behaviour simulation tools to predict the potential spread of a fire in both risk planning and operationally during wildfires. These models are generally based on underlying empirical or quasi-empirical relations and rarely are uncertainties considered. Little attention has been given to the quality of the input data used during operational fire predictions. We examined the extent to which error in weather forecasts can affect fire simulation results. The study was conducted using data representing the State of Victoria in south-eastern Australia, including grassland and forest conditions. Two fire simulator software packages were used to compare fire growth under observed and forecast weather. We found that error in the weather forecast data significantly altered the predicted size and location of fires. Large errors in wind speed and temperature resulted in an overprediction of fire size, whereas large errors in wind direction resulted in an increased spatial error in the fire{\textquoteright}s location. As the fire weather intensified, fire predictions using forecast weather under predicted fire size, potentially resulting in greater risks to the community. These results highlight the importance of on-ground intelligence during wildfires and the use of ensembles to improve operational fire predictions.

}, keywords = {Bayesian Network, fire prediction, meteorological forecast, sensitivity, simulation}, doi = {https://doi.org/10.1071/WF19199}, url = {https://www.publish.csiro.au/wf/wf19199}, author = {Trent Penman and Dan Ababei and Jane Cawson and Brett Cirulis and Thomas Duff and Swedosh, W and James Hilton} } @article {bnh-7495, title = {Fire coalescence and mass spot fire dynamics: experimentation, modelling and simulation {\textendash} annual project report 2019-2020}, number = {625}, year = {2020}, month = {11/2020}, institution = {Bushfire and Natural Hazards CRC}, address = {MELBOURNE}, abstract = {

This report outlines the progress of the Fire Coalescence and Mass Spot Fire Dynamics project, which is one of the projects within the Next Generation Fire Modelling cluster. Specifically, the report summarises progress of the first two years of the second phase of the project, which has been extended over 2018-2021.

All milestones from the 2015-2018 phase of the project have now been delivered, and the project is continuing to build upon this work in delivering important insights into the dynamics of fire behaviour and fire line interaction. Phase 2 of the experimental program is in progress, and will extend recently published work from Phase 1. The project continues to yield important and significant insights into the behaviour of coalescing fires, and these insights are enhancing our understanding of the processes driving fire propagation and the way we model dynamic fire behaviours. \ 

In particular, the research has continued to develop the pyrogenic potential model by incorporating firebrand dynamics. This has resulted in the world{\textquoteright}s first capability to model dynamic modes of fire propagation such as vorticity-driven lateral spread using a two-dimensional simulation framework with a spotting module. This means that explicitly modelling such effects in operational timeframes is now a feasible option. The research has also examined how wind-terrain interaction influences ember trajectories and the likely distribution of spot fires down wind of complex terrain.

In the past year, the project team have delivered a number of research outputs, including conference presentations and posters and journal publications. Still more publications are in preparation. The project team has also delivered on a number of key utilisation activities. These have mainly involved discussions with key end users about the prospects of the research being incorporated into education materials and training resources for firefighters and fire behaviour analysts. The project has also begun working on a dedicated utilisation project aimed at development of spot fire spatial mapping tools.

After providing some background information on the project{\textquoteright}s aims and methodology, this report provides details on the progress of the project to date. In particular, this includes:

At the time of writing, the project is on-schedule.

}, keywords = {experimentation, fire coalescence, mass spot fire dynamics, modelling, simulation}, issn = {625}, author = {Jason J. Sharples and James Hilton and Sullivan, Andrew and Badlan, R} } @article {bnh-6811, title = {Fire coalescence and mass spot fire dynamics: experimentation, modelling and simulation - Annual project report 2018-2019}, number = {559}, year = {2020}, month = {03/2020}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

This report outlines the progress of the Fire Coalescence and Mass Spot Fire Dynamics project, which is one of the projects within the Next Generation Fire Modelling cluster. Specifically, the report summarises progress of the first year of the second phase of the project, which has been extended over 2018-2021.

All milestones from the 2015-2018 phase of the project have now been delivered, and the project is continuing to build upon this work in delivering important insights into the dynamics of fire behaviour and fire line interaction. Phase 2 of the experimental program is in progress, and will extend recently published work from Phase 1. The project continues to yield important and significant insights into the behaviour of coalescing fires, and these insights are enhancing our understanding of the processes driving fire propagation and the way we model dynamic fire behaviours. \ 

In particular, the research has continued to develop the pyrogenic potential model by incorporating the effects of pyrogenic vorticity. This has resulted in the world{\textquoteright}s first capability to model dynamic modes of fire propagation such as vorticity-driven lateral spread using a two-dimensional simulation framework. This means that explicitly modelling such effects in operational timeframes is now a feasible option. Coupled fire-atmosphere simulations continue to provide fundamental insights that will be drawn upon to inform further the development of the pyrogenic potential model.

In the past year, the project team have delivered a number of research outputs, including conference presentations and posters and a journal publication (currently under review). A number of other publications are in preparation. The project team has also delivered on a number of key utilisation activities. These have mainly involved discussions with key end-users about the prospects of the research being incorporated into education materials and training resources for firefighters and fire behaviour analysts.

After providing some background information on the project{\textquoteright}s aims and methodology, this report provides details on the progress of the project to date. In particular, this includes:

At the time of writing, the project is on schedule.

}, keywords = {experimentation, fire coalescence, modelling, simulation, spot fire dynamics}, issn = {559}, author = {Jason J. Sharples and James Hilton and Sullivan, Andrew} } @mastersthesis {bnh-6632, title = {Physics-based simulation of short-range spotting in wildfires}, year = {2020}, month = {01/2020}, school = {Victoria University}, address = {Melbourne}, abstract = {

Firebrands play a vital role in the propagation of fire fronts and starting new fires called spotfires ahead of fire fronts during wildfire progression. Firebrands are a harbinger of damage to infrastructure; their effects cause a particularly important threat to people living within the wildland-urban-interface, hampers the suppression of the wildfire or even blocking the evacuation routes for communities and emergency services. Short-range firebrands (\<750m) which travel along with the wind with little or no lofting are particularly crucial in increasing the fire front propagation and damaging structures situated closed to wildland-urban interface. In the Daylesford fire of 1962, massive short-range spotting (the process of spot fire ignition and merging of spots caused by firebrands) occurred in eucalyptus forest and increased the rate of fire spread by roughly three times more than the computed using empiricial correlation used by operational fire model. Despite the massive importance of short-range firebrands, little research has been conducted because of the safety risks and challenges of fire to emergency service personnel and to the remote equipment like collection boxes, IR cameras, UAVs, which could be used by researchers to quantify and measure fire properties. An operational model to represent the transport of short-range firebrand and their likelihood to ignite the surface fuel like forest litter could be developed from a numerical model. This study first attempts to validate a numerical model of firebrand transport with a set of benchmark experiments. The validation of numerical model is carried out using idealised regular shaped firebrand. Fire Dynamic Simulator (FDS) is an open-source Computational Fluid Dynamics (CFD) based fire model which is used in this study. The validation of the numerical model is split into two parts focusing on validation of (1) transport, and (2) ignition potential of firebrands. Transport of short range firebrands are modelled in FDS using a lagrangian particle sub-model. The model was validated using two firebrand generators (a plastic pipe-based prototype and stainless steel based main firebrand generator) constructed at our facility as a part of this study. The firebrand generator is equipment which generates a repeatable firebrand shower in a confined space. There are few firebrand dragons built around the world. However, our firebrand generators produce a uniform flow field which simplifies the transport of short-range firebrand to be validated. The set of experiments conducted is used to validate the Lagrangian particle model available in FDS used in the transport of short-range firebrands. The validation is carried out on cubiform, cylindrical, and square disc-shaped firebrands. As the default drag model in FDS was not suitable for shapes of firebrands, the drag model is improved to account for a generic shape of firebrand particle. The results show a reasonable agreement with the experiments for all three shapes over a range of particle Reynolds number. A set of laboratory scale equipment is used to study the ignition likelihood from a short-range firebrand in the numerical model. The boundary fuel vegetation model of FDS is validated. The pyrolysis of vegetation is first tested using thermogravimetric analyser and then with cone calorimeter to estimate mass loss rate, heat-release rate, and time to sustained flaming ignition of three forest litter (pine, eucalyptus, and hay) fuels. Further, a set of thermo-physical properties (thermal conductivity, heat capacity, the heat of pyrolysis, the heat of combustion) of the material tested are also measured using in-house equipment required in the above numerical model. The result showed that the simple linear pyrolysis model is good enough for different forest litter tested with thermogravimetric analyser and cone calorimeter. Finally, a parametric study of short-range firebrand transport inside an open woodland forest canopy is carried out using the validated Lagrangian particle sub-model. The work focuses on understanding how firebrand distribution varies with a set of variable firebrand characteristics in a wildfire and set a stepping stone for the future study. The results are found to be qualitatively similar to the literature.

}, keywords = {Fire, Firebrands, fluid dynamics, simulation, spotting, transport, Wildfire}, url = {http://vuir.vu.edu.au/40025/}, author = {Rahul Wadhwani} } @article {bnh-6567, title = {Simulation optimisation for natural hazard risk management}, number = {533}, year = {2020}, month = {01/2020}, institution = {Bushfire \& Natural Hazards CRC}, address = {Melbourne}, abstract = {

In this report, we outline a decision-support framework for natural hazard management that combines the use of simulation and optimisation for exploring what risk reduction measures best achieve management priorities. This framework addressed several needs that practitioners have with regard to risk and adaptation assessment. First, it uses optimisation approaches to screen through and identify those management options that perform best across a number of decision criteria. This is important, as there are a very diverse range of management options which could be combined in an extremely large number of ways to make portfolios of management options and it is difficult to screen through all potential portfolios to shortlist a small number for further consideration. Second, it simulates the effectiveness of management options over long-term planning horizons. This is important, for management options may have long lead-in-times, and/or may have long lifetimes, are not easily/readily changed, and so need to be effective over a broad range of plausible future conditions, which likely include larger populations, increased economic development and climate change. Third, the framework emphasises holistic assessment, wherein the Integrated assessment modelling (IAM) simulates the effect of management options across a number of criteria, therefore allowing practitioners to explore the trade-offs between risk reduction with other community goals, including environmental, social and economic outcomes.


The value of this framework arises from the greater demands that are being placed on planners to effectively manage natural hazard risk, whether from politicians or from the public who have an increasingly reduced appetite for hazard losses. This creates a need for analytic frameworks for exploring how to best manage risk, and this framework addresses this gap.


Through application to a case study, this report shows how the framework is able to increase the effectiveness and efficiency by which IAM can be applied to natural hazard risk management. The role of the optimisation was seen not to be prescriptive, but to enable better exploration of risk management options. The framework was therefore able to provide rich information on the effectiveness of management portfolios by which better risk management plans could be formed.


The case study to which the framework was applied considered coastal flood risk within Greater Adelaide and explored the combinations of zonal exclusion areas along the coast which prevented further development. If unmitigated, coastal risk could increase by 10\% over the next three decades. However, results of the case study application showed that zonal exclusion policies could effectively reduce this growth of coastal risk, however this required excluding further development from 7000 Ha of land along the coast. Saying that, the growth in risk could be limited to 3\% (i.e. a reduction in growth by 60\%), through excluding coastal development from only 1500 Ha.

}, keywords = {natural hazard, optimisation, risk management, simulation}, issn = {533}, author = {Jeffrey Newman and Graeme Dandy and Aaron Zecchin and Hedwig van Delden and Charles Newland and Holger Maier and Graeme Riddell} } @conference {bnh-6407, title = {Modelling the vulnerability of a high-set house roof structure to windstorms using VAWS }, booktitle = {Bushfire and Natural Hazards CRC Research Day AFAC19}, year = {2019}, month = {12/2019}, address = {Melbourne}, abstract = {

Modelling the vulnerability of houses in windstorms is important for insurance pricing, policy-making, and emergency management. Vulnerability models for Australian house types have been developed since the 1970s and have ranged from empirical models to more advanced reliability based structural engineering models, which provide estimates of damage for a range of wind speeds of interest. This paper describes recent developments in the engineering based vulnerability modelling software: {\textquoteleft}Vulnerability and Adaption to Wind Simulation{\textquoteright} (VAWS), which uses probability based reliability analysis and structural engineering for the loading and response coupled with an extensive test database and field damage assessments to calculate the damage experienced by selected Australian house types. A case study is presented to demonstrate the program{\textquoteright}s ability to model progressive failures, internal pressurization and debris impact.

}, keywords = {debris, simulation, structures, VAWs, Vulnerability, wind}, url = {https://knowledge.aidr.org.au/resources/australian-journal-of-emergency-management-monograph-series/}, author = {Korah Parackal and Martin Wehner and Hyeuk Ryu and John Ginger and Daniel Smith and David Henderson and Mark Edwards} }