End User representatives
Fire behaviour in dry eucalypt forests in Australia is characterised by the occurrence of spotfires—new fires ignited by the transport of embers ahead of an existing fire. Under most burning conditions, spotfires play little role in the overall propagation of a fire, except where spread is impeded by breaks in fuel or topography. Spotfires allow these impediments to be overcome.
However, under conditions of severe bushfire behaviour, spotfire occurrence can be so prevalent that spotting becomes the dominant propagation mechanism and the fire spreads as a cascade of spotfires forming a ‘pseudo’ front.
It has long been recognised that the presence of multiple individual fires affects the behaviour and spread of all fires present. The converging of separate individual fires into larger fires is called coalescence and can lead to rapid increases in fire intensity and spread rate, leading to the phenomenon of a ‘fire storm’. This coalescence effect is frequently used in prescribed burning, with multiple point ignitions used to rapidly burn out large areas.
This project is focusing on:
- Fire coalescence to provide better predictions of fire propagation
- The intrinsic dynamics of flame front propagation as a contributor to fire spread across different spatial and temporal scales
- Within a simulation framework an end-to-end model of the behaviour of mass spotfires, from firebrand/ember launch to fire coalescence.
The project is employing sophisticated mathematical modelling techniques in combination with laboratory and field experiments.
The research is investigating the role that fire line geometry (especially curvature) plays in the dynamic propagation of bushfires. The project has demonstrated that fire propagation models incorporating curvature dependence can out-perform quasi-steady (first-order) models when applied to simple wind-driven fires at both laboratory and field scales.
In addition, the research has produced a number of fundamental insights into how the shape of the fire line can affect the pyroconvective interactions between different parts of a fire. These insights have mostly been gained by targeted simulations using a coupled fire-atmosphere model.
|2016||Journal Article||Natural hazards in Australia: extreme bushfire. Climatic Change 139, 85-99 (2016).|
|2016||Journal Article||Curvature effects in the dynamic propagation of wildfires. International Journal of Wildland Fire 25, (2016).|
|2016||Report||Fire coalescence and mass spot fire dynamics: experimentation, modelling and simulation: Annual project report 2015-2016. (Bushfire and Natural Hazards CRC, 2016).|
|2015||Presentation||Dynamic modelling of fire coalescence. (2015).|
|2015||Report||Fire coalescence and mass spotfire dynamics: Experimentation, modelling and simulation - Annual project report 2014-2015. (Bushfire and Natural Hazards CRC, 2015).|
|04 Dec 2014||Fire coalescence and mass spotfire dynamics||704.99 KB (704.99 KB)||fire, fire severity, modelling|
|22 Mar 2016||Severe and High Impact Weather - cluster overview||0 bytes (0 bytes)||fire, modelling, scenario analysis|
|20 Oct 2016||Fire coalescence and mass spotfire dynamics - project overview||0 bytes (0 bytes)||fire impacts, fire severity, fire weather|
|24 Oct 2016||Fire coalescence and mass spot fire dynamics||4.18 MB (4.18 MB)||fire, fire impacts, fire weather|
|25 Oct 2016||Next generation fire modelling||1.35 MB (1.35 MB)||fire impacts, fire severity, fire weather|
|27 Feb 2017||Fire Australia Issue One 2017||5.79 MB (5.79 MB)||child-centred, fire severity, resilience|
Spotting can be the dominant fire propagation mechanism during times of extreme fire weather. Spot fires can merge and collapse on one another creating regions of deep flaming, which produce violent pyroconvection. Understanding and modelling the intrinsic dynamics of spot fire coalescence is an important step in providing ways of mitigating the effects of extreme fires.
Predictive models of natural hazards have become a necessity for emergency management, mitigation and adaptation planning.
|Natural hazard exposure information modelling framework||Dr Krishna Nadimpalli||Geoscience Australia|
|Determining threshold conditions for extreme fire behaviour||Dr Trent Penman||University of Melbourne|
|Coupled fire-atmosphere modelling||Mika Peace||Bureau of Meteorology|