An Application of the Level-set Method to Fire Front Propagation

Wildland fire models and simulators developed in the last two decades are increasingly applied in different ecosystems and countries of the world to predict fire behavior and effects. Fire models range from empirical formulas, such as the ones defined by Rothermel and applied in spatially and temporally explicit fire simulators (i.e. Farsite), to complex three-dimensional CFD approaches solving the partial differential equation of continuity, momentum and energy. The wide range of length and time scales governing wildland fire (from the millimeter scale of combustion processes to the hundreds of meters scale of synoptic wind flow) complicates the use of a full-3D numerical approach, at least for operational forecasting purposes. At the same time, there is an important two-way influence between weather and fire: wind determines fire propagation and, conversely, the buoyancy effects generated by fire heat modify the local wind field, -creating their own weather?. A possible solution to this problem is the use of a simpler (and thus computationally cheaper) model to describe fire propagation, while maintaining a CFD approach to model wind behavior and, more importantly, the two-way interaction due to fire heat release. A number of studies applied this approach in the last few years [1]. This work describes the initial steps in the development of a model for fire-front propagation based on a level-set methodology and its integration into a CFD model.