Local measurements of wildland fire dynamics in a field-scale experiment

Local point measurements of fire dynamics in field-scale experiments of wildland fires are highly useful. This is true both for understanding the mechanisms driving fire spread that result in the observed macroscopic behaviors, but also in terms of providing comparison points for numerical tools, such as detailed physics-based fire behavior models. This work describes measurements of temperature, velocity, and radiative heat flux that were made in a field-scale fire experiment in a pine forest, with the aim of providing both of the above benefits. Regions of both surface fire and crown fire were captured and are compared. The crown fire exhibited tall upright flames, compared to the shorter tilted flames of the surface fire. Crown fire resulted in a significant increase in integrated radiative preheating, by a factor of ∼1.75, as well as greater flow sheltering in the downstream region of the fire front. Further, a corrective factor is introduced for oblique sensor placement relative to the fire front, in order to improve the value of these and other measurements, particularly for model comparison. The presented methodology, while able to be improved, is shown to successfully characterize local differences in fire behavior.