Comparison of the effect of one-way and two-way fire-wind coupling on the modelling of wildland fire propagation dynamics

Operational wildland fire propagation models are typically uncoupled from the wind field or they rely either on estimations extracted from an atmospheric model or on meteorological observations. This leads to a frozen wind field (one-way coupling) with a high degree of uncertainty, thus drifting away from the ground truth. In contrast, fully-coupled models (two-way coupling) comprise more accurate representations of the real phenomena, although they are not viable for operational use due to the hefty computational effort they entail. This article investigates and compares the effects of one-way and two-way wind-fire coupling on the predicted propagation of wildfires. The models are validated against experimental data obtained from grassland experiments carried out by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia. Simulations are carried out on a flat surface and for different wind speeds. Two scenarious are considered, one with and the other without an obstactle affecting both the wind flow and the wildfire propagation. Results from the simulations indicate that the burnt area and the rate of spread (RoS) are both smaller in two-way coupled than in one-way coupled models.