Numerical simulation of two parallel merging wildfires

Background. Wildfire often shows complex dynamic behaviour due to the inherent nature of ambient conditions, vegetation and ignition patterns. Merging fire is one such dynamic behaviour that plays a critical role in the safety of structures and firefighters. Aim & method. The aim of this study was to develop better insight and understanding of the interaction of parallel merging firelines, using a numerical validation of a physics-based CFD wildfire model concerning merging fires. Conclusions. The validated model shows a relative error of 5–35% in estimating the rate of fire spread compared with the experimental observation in most of the cases. A physical interpretation is presented to show how parallel fire behaves and interacts with the ambient conditions, providing complementary information to the experimental study. Implications. The validated numerical model serves as a base case for further study in developing a better correlation for the rate of fire spread between parallel firelines with different ambient conditions, especially at the field scale.