Background: Understanding near-surface fire–atmosphere interactions at turbulence scale is fundamental for predicting fire spread behaviour.
Aims: This study aims to investigate the fire–atmosphere interaction and the accompanying energy transport processes within the convective boundary layer.
Methods: Three groups of large eddy simulations representing common ranges of convective boundary layer conditions and fire intensities were used to examine how ambient buoyancy-induced atmospheric turbulence impacts fire region energy transport.
Key results: In a relatively weak convective boundary layer, the fire-induced buoyancy force could impose substantial changes to the near-surface atmospheric turbulence and cause an anticorrelation of the helicity between the ambient atmosphere and the fire-induced flow. Fire-induced impact became much smaller in a stronger convective environment, with ambient atmospheric flow maintaining coherent structures across the fire heating region. A high-efficiency heat transport zone above the fire line was found in all fire cases. The work also found counter-gradient transport zones of both momentum and heat in fire cases in the weak convective boundary layer group.
Conclusions: We conclude that fire region energy transport can be affected by convective boundary layer conditions.
Implications: Ambient atmospheric turbulence can impact fire behaviour through the energy transport process. The counter-gradient transport might also indicate the existence of strong buoyancy-induced mixing processes.