Image showing computational fluid dynamics model of competitive combustion, with central red region radiating outwards through orange, yellow, green and blue.

Bushfire behaviour and Complex Systems Science

An emerging field of study using advanced mathematical physics is helping researchers to better understand and model bushfire behaviour.

  • 12 May 2008 | Updated 14 October 2011

The behaviour and spread of bushfires are determined by factors such as fuel, topography, atmospheric conditions and the fire itself.

Current methods of bushfire research rely upon reducing the range of possible combinations of conditions in order to investigate manageable problems.

However, it is recognised that the interactions between the variables, which occur over a wide range of spatial and temporal scales and are possibly non-linear, can have a critical role in fire behaviour.

Complex Systems Science (CSS) is an emerging field of study that utilises advanced techniques and methods in mathematical physics to investigate these interactions without reducing the complexity of the original problem.

Aims

This project aims to apply Complex Systems Science to provide an additional dimension to the study and quantification of bushfire behaviour.

Scientists aim to explore the apparent modes of stable behaviour, witnessed when large bushfires appear to integrate relatively large perturbations in variables (such as wind and fuel), and unstable behaviour, when relatively minor changes in variables result in dramatic and unexpected changes in fire behaviour that catch firefighters unaware, with disastrous results.

The project aims to apply CSS to study unstable behaviour, when minor variable changes result in dramatic changes in fire behaviour.

Methods

Techniques such as computational fluid dynamics, dynamical systems theory (including stability analysis and bifurcation theory), cellular automata and renormalisation group theory will be investigated in the context of a comprehensive historical dataset of grassland fire behaviour obtained from field experiments conducted in the mid-1980s by CSIRO.

Results will be used to develop a model of fire behaviour that encompasses the major interactions relevant to the spread of bushfires.

The current phase of research is exploring the understanding of cellulose combustion and investigating the role advection has on the propagation of the fire perimeter.

Read more about CSIRO research in Bushfires.