Slope effect on Junction Fire with Two Non-symmetric Fire Fronts.

Abstract

The merging of two linear forest fire fronts that intersect at a small angle creates an accelerating fire in a relatively short time. In the majority of cases during the interaction, the fire fronts are non-symmetric. In Pedrogão Grande on the 17th June 2017, two-fire front merged and the propagation of the fire was influenced by the interaction of these two non-symmetric fire fronts. This forest fire motivates us to study the Junction Fire with two non-symmetrical fire fronts. The analysis of the interaction of point A and the angle between the bisector of the fire lines and the maximum ROS () is of particular relevance. It is found that with these preliminary laboratory tests, the non-ROS of point A for small rotation angles () depends on the slope angle () and the initial angle between fire fronts. For the highest slope angles, the non-ROS is the highest influence by the convection process, and the angle  where the maximum ROS occurred, increases when  increases. However, for the lowest slope angles, the radiation process is dominant and influences the non-ROS. For these cases, the angle ï§ï€ is near to the bisector of the fire lines.