Fire Simulation with Dry Eucalyptus & Flat Terrain
| In the past, studies and numerical simulation of forest fires have treated the fire-atmosphere as an uncoupled system. The simulation we show here from 1997 is particulary interesting because a simple, dry-eucalyptus fire model is fully coupled with an atmospheric model to conduct the study. Both ground and canopy fuels are prescribed as are winds, which are forced in a hyperbolic-tangent profile, with 3 m/s at surface and -3 m/s at top of the domain which is 1 km. | ||||
| Buoyancy, Iso=.2, Frontview | Buoyancy, Volume, Frontview | Buoyancy, volume-rendered with particle advection | ||
The volume visualization represents the buoyancy field, not the fire itself, even though it looks like the fire. |
Lofted burning particles were examined to see if they might be tossed out in front of the fire, thus participating in the propagation of the event. |
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| Vorticity, Iso=+/-.2, Frontview | Vertical Vorticity, Isosurfaces, Frontview | |||
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The vertical vorticity field is basically a measure of the rotation about the vertical axis, and provides a good rendering of the two counter-rotating vortices that appear on each edge of the fire late in the simulation. Such behaviour is often observed in naturally occuring fires. In this simulation, these vortices approach tornadic strength. |
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Abstract from Clark, Coen, et al paper:
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"A numerical atmospheric model is coupled with a simple dry eucalyptus forest fire model to create a wildfire simulation model. This is used to show how certain atmospheric conditions can lead to commonly observed forest fire behaviour. Using short line fires, simulations show that with moderate winds, the fire line interacts with the updraft ahead of it causing the fire line to curve forward into a conical shape. Other experiments show that when ambient winds change with height, a pair of rotating updrafts at the curved fire front can touch down within the fire and break up the fire line. We also demonstrate "dynamic fingering", in which the rotating columns near the fire front intensify to tornado strenth and can result in rapid and strong increases in the fire spread rate."
| Model | |
Model Name: |
Clark Fire Model, FR7CS1 |
| Data | |
Time Resolution: |
5 seconds |
Timesteps: |
336 |
| Domain | |
Horizontal Real World: |
1 x 1 km |
Vertical Real World: |
1 km |
Horizontal Resolution: |
60 x 60 |
Vertical Resolution: |
26 |
| Visualization | |
Visualization: |
Don Middleton |
Software: |
Vis5D with enhancements to support particles |
Hardware: |
Onyx |
CPU Time: |
~ 1 day |
| Project | |
Scientists: |
Terry Clark Janice Coen |
Date Created: |
1997 |
Date Catalogued: |
2002-08-05 |
Rights: |
© 2002, UCAR, All rights reserved. |
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