Physical Modeling of Surface Fire Under Nonparallel Wind and Slope Conditions

Abstract

The physical model we developed in a previous work (J. H. Balbi et al., 2007) predicts fire behavior with a computational time that is faster than real time. However, it has the inconvenient of introducing an empirical law (B. J. McCaffrey, 1979), which provides flame height according to heat release rate. The authors introduce two improvements of this model: the triangular flame hypothesis and a modification taking into account the air cooling on the rear fire front. To test this variant of their simplified model, it was compared with important experimental results (D. X. Viegas, 2004b). The experiments were performed in homogeneous and plane fuel beds made with dead Pinus pinaster needles under high values of wind and slope. In spite of these high values this physical model provides a good approximation of the fire front perimeter.

Keywords:

• Fire spread contours
• Nonparallel wind and slope
• Physical model

ACKNOWLEDGEMENTS

The present work was partially supported by the Research National Agency under contract N° NT05-2_44411.