How can CFD contribute to the understanding of wildfire behaviour?

Abstract

In addition to the experimental approach, wildfire modelling has been developed over the last decades to better understand the behaviour of wildfires and to propose new management tools to evaluate and reduce this natural hazard. This paper has twofold objective: (1) show how CFD simulation carried out using fully-physical models contributes to the understanding of wildfire behaviour, and (2) present new developments that were brought to FireStar3D – a fully-physical multiphase fire-simulator. The multiphase approach used in this class of models is briefly described, as well as the difficulties arising from the coupling between the various physical mechanisms of this multiscale problem. LES modelling and turbulence-radiation interaction used in FireStar3D is particularly detailed, as well as a new inlet boundary condition allowing to account for fire-induced flow while maintaining a prevailing crosswind far from the flaming zone. The benefits of multiphase CFD approach in addressing wildfire problems is demonstrated by considering three case studies of static and propagating vegetation fires having different length scales, which also highlights the model's potential in various configurations.