XXXIV Meeting of the Italian Section of the Combustion Institute 1 EFFECTS OF WIND AND TERRAIN SLOPE ON FLAMES PROPAGATION IN A VEGETATIVE FUEL BED L. Malangone, P. Russo, S. Vaccaro lmalangone@unisa.it Department of Industrial Engineering, University of Salerno, Fisciano, Salerno, Italy Abstract In this work the way the wind and terrain inclination affect the fire propagation across a homogeneous fuel bed was investigated. The role played by these two parameters in fire behaviour was studied, showing that wind velocity affects the rate of spread more strongly than the terrain slope. The evolution of a fire front from a linear ignition source was analysed along with the time evolution of the fire front according to the external condition. The role played by the terrain slope and atmospheric wind in determining the rate of spread was quantified, showing how the latter parameter has a stronger dependency on the rate of fire spreading. 1. Introduction Wind and topographic slope are commonly considered to be the main factors determining wildfires propagation [1]. Wind has the effect of tilting the flame forward, increasing convection and radiation transfer of energy to the unburnt fuel, inducing faster rate of spreads. Slope effect is often described as being similar, because it tends to make the ground and the fuel closer [2]. Consequently, most wildfire behaviour models and fire behaviour prediction systems take account of the wind and slope effects when computing the rate of spread [2, 3, 5]. In order to analyze the complexity of the fire phenomena according to a numerical point of view aiming to provide information about the behaviour of fire spreading, semi-empirical and empirical approaches were considered. However, due to their intrinsic limits to correctly quantify the fire propagation rate, since the late 1990, a physically-based approach has been followed to develop two-phase flow transport models that explicitly take into account the interaction between the gaseous phase and the fuel to model accurately the convective heat transfer [6, 7]. Among physically-based models, WFDS is a three-dimensional two-phase transport model that solves the conservation equations for mass, momentum, energy and chemical species. Because of these attributes, this model can be a valuable tool for the investigation of the slope effects under various conditions of wind and terrain inclinations. This issue was accomplished by comparing the results of the model simulations with some findings from experimental tests available in the literature.