Fundamental Wildland Fire Spread Research

Current operational fire behavior models are empirically based on fire spread through surface fuels and do not describe heating and combustion processes. Current physical models describe fire spread processes; however, the fire spread processes of heat exchange and ignition are assumed without an experimental basis. FFS researchers and collaborators have developed a program of research for understanding how fire spread occurs with a focus on live fuels and active crown fire. Specific fire dynamics research investigations include:

Please see the Downloads & Users Guide section for videos of our experiments.

Image: Convection heat transfer requires flames to contact adjacent fuels. Discontinuous fuels (e.g. shrub and tree canopies) require flames to extend across gaps between fuel clusters. The vertical flame wall with its high sample rate heat flux sensors (shown) and thermocouples are used to describe flame turbulence and thus the flame position and duration. Diffusion flames are produced using buoyantly neutral ethylene fuel gas.

Images

Convection heat transfer requires flames to contact adjacent fuels. Discontinuous fuels (e.g. shrub and tree canopies) require flames to extend across gaps between fuel clusters. The vertical flame wall with its high sample rate heat flux sensors (shown) and thermocouples are used to describe flame turbulence and thus the flame position and duration. Diffusion flames are produced using buoyantly neutral ethylene fuel gas.

Audio and Video

Video file

Summary of buoyant dynamics observed in flames from laboratory wind tunnel burns.

Video file

Prescribed grass fire at Camp Swift Texas showing regular saw-tooth flame structures.

Video file

Burn 53, wind speed 0.335 m/s, flame length 0.6 m.

High speed video (300fps) of flame structure in cardboard fuel arrays burning in the large wind tunnel.

Video file

Burn 56, wind speed 0.955 m/s, flame length 0.4 m.

High speed video (300fps) of flame structure in cardboard fuel arrays burning in the large wind tunnel.

Video file

Burn 56, wind speed 0.955 m/s, flame length 0.4 m.

High speed video (300fps) of flame structure in cardboard fuel arrays burning in the large wind tunnel.

Video file

High speed video (300 fps) showing side view of coherent flame structures rolling forward of the fire front into un-ignited fuel particles.

Video file

Flow tracking analysis reveals flame movement in spreading fires.

Video file

CO2 and water vapor used to visualize vorticity over a heated plate.

Video file

Stationary ethylene gas burner showing flame dynamics and structure similar to spreading fires.

Video file

Vorticity patterns visualized by smoke behind the fire front.