Physical Modeling of Surface Fire Under Nonparallel Wind and Slope Conditions

The physical model we developed in a previous work (J. H. Balbi et al., 2007 Balbi , J.H. , Rossi , J.L. , Marcelli , T. , and Santoni , P.A. 2007 . A 3D physical real-time model of surface fires across fuel beds . Combustion Science and Technology , 179 , 2511 – 2537 .[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]) 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 McCaffrey , B.J. 1979 . Purely buoyant diffusion flame: Some experimental results . NBSIR , 79-1910 . [Google Scholar]), 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 Viegas , D.X. 2004b . Slope and wind effects on fire propagation . International Journal of Wildland Fire , 13 , 143 – 156 .[Crossref], [Web of Science ®] , [Google Scholar]). 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.