THE INFLUENCE OF WIND ON THE STRUCTURE OF INCLINED FLAMES

Abstract

Experiments were performed using stationary gas burners in order to characterize the flame geometry and downstream heating from stationary flames under inclined configurations under an applied forced flow. Stationary flames exhibit behavior similar to spreading wildland fires but are an ideal configuration for carefully studying fundamental wildland fire behavior characteristics that play a critical role in downstream heating, which subsequently drive fire spread. Two conditions were applied to a small-scale apparatus during experimentation, a sloped surface and forced-flow wind. The experiments were performed at multiple heat-release rates for angles from 0 to 28 degrees from the horizontal and wind speeds of 0 to 0.5 m/s.Flame geometry such as center-line flame length, flame tilt angle, and flame attachment length along the downstream surface were determined from side-view video imaging. Downstream heating was also measured through fine-wire thermocouple temperature measurements and surface total heat heat flux measurements. The measurements provided a heating profile depicting the magnitude of heating that would be applied to unburned fuels at distances in front of a spreading fire. These profiles were compared to the flame attachment observed from imaging, and to one another. While the surface heat flux cannot be scaled to larger fires, it’s relation to temperature profiles will be useful to further interpret large-scale experiments and as validation data for numerical modeling of fire behavior of the combined effects of slope and wind