NIST Wildland-Urban Fire Models (Downloads)(these models are in the early stages of validation)
This page contains links to NIST's wildland-urban interface fire
computer models and example input files. Validation of these models is ongoing but far from
complete. Please keep this in mind when using wfds for problems outside
the current scope of validation. See download sections below for
information on the current state of validation.last updated February, 2009 |
In general please use the FDS discussion group and issue tracker when you have questions (see http://fire.nist.gov/fds/). Refer to WFDS. My (William [Ruddy] Mell) e-mail address is ruddy@nist.gov For new users please send me an e-mail so that I can inform you when new versions, capabilities, and a user guide are available. |
WFDS for fuels in a specified volume such as tree crowns (fuel element model) | |
Validation of
fuel element
model to date:
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WFDS program
downloads with fuel element model. Note: This implementation of WFDS is fully incorporated in the current version of FDS, so if you have the current version of FDS you already have WFDS with the fuel element model representation of vegetation. When posting to the FDS Issue Tracker or the Discussion Group regarding the application of FDS to wildland or wildland-urban interface fires please refer to WFDS in your text to facilitate searches and so we can streamline our response.
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Input files
using fuel
element model Vegetation can be described by a rectangular, conical, or cylindrical volume. In the input files below you'll find surface fuels described by a rectangular volume (e.g., pine needles), crown fuels as conical volumes, and tree stems as cylindrical volumes. The stems are present to serve as wind breaks and do not burn. If you are including stems please following the format of the input files. CPU timings given below were obtained on a duo quad core Linux computer with 3.5 GHz processors. |
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Single processor input file: input_surf_onetree_1proc.txt Run by typing (in Windows command window) wfsd32.exe surf_onetree_1proc.fds Two processor input file: input_surf_onetree_2proc.txt Run by typing (in Windows command window with MPICH2) mpiexec -n 2 wfds32_mpi.exe surf_onetree_2proc.fds |
Burning pine needle bed (5 cm deep), temperature plume, tree foliage, and tree stem. Domain is 16 m long (160 grid cells, dx=10 cm), 3 m wide (30 grid cells, dy=10 cm), and 6 m tall (60 grid cells, dz = 5 cm at ground to 20 cm at top). Mirror or symmetry boundary conditions are used along y = 0 plane. Axes units are meters. Simulation time is 60 s which requires about 2.2 cpu hours. About 200 MB of memory is required. The 2 processor simulations required 1.2 cpu hours on each processor (total elasped wall clock time was also 1.2 hours, this includes start up and writing out data files) |
Single processor input file input_grass_trees_flat_1proc.txt Two processor input file: input_grass_trees_flat_2proc.txt |
About 90 identical 6 m tall, 3 m wide, cone shaped trees are randomly distributed across a 30 m wide and 25 m long area. Axes units are meters. A 0.5 m tall grass is underneath the trees. The grass is ignited on the upwind side. The wind speed is uo = 2 m/s at the x=0 plane. Grid resolution is 0.5 m in all directions. Note that, unlike the more resolved (~7.5 cm grids) isolated tree simulations, validation of the fuel element model at this resolution has not been completed. The simulation time is 60 s and requires about 25 cpu minutes for a single processor run and about About 200 MB of memory is required. The trees in the above image are colored according to the temperature of the crown vegetation. |
no input file presently |
Fire, trees, and smoke plume. Same domain size and tree definition as above. Axes units are meters. Fire is held stationary with bed dimensions of 2 m deep by 30 m long with a heat release rate of 500 k/m^2 (based on Australian grassland fires). Simulation time is 30 s which requires about 9 cpu minutes on a 3.8 GHz processor. About 200 MB of memory is required. |
Mock-up of deep fuel bed experiments. input_deep_fuel_bed_2p5mBY2m.txt |
Semi-2D mock up of deep fuel bed experiments. This is preliminary since fuel properties and bulk geometry are unknown. Fire spread is clearly too fast - which is also due to assuming a 2D geometry. Single processor run required about 3.5 minutes for 60 s simulated time. |
3D Run of deep fuel bed experiments input_deep_fuel_bed_3m2m2m_4mesh.txt Input file that has examples of the use massless tracers input_dfb_tracers.txt Input file that has |
Deep fuel bed simulation in 3D domain 3 m x 2 m x 2 m. Four meshes are used. When each mesh is assinged a processor (i.e., four process run) the 60 sec simulation takes about 20 minute (but the fire extinguishes after 10 s). |
WFDS for surface
fuels such as grassland fuels (boundary fuel model) Under development - All links below are for a currently unsupported version of WFDS |
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Validation of
boundary fuel model to
data:
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WFDS program
downloads with boundary fuel model
<> |
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Input files with
boundary fuel model Vegetation is present on the bottom of the computational domain as a surface fuel. It can be thought of as being "painted" on. Note that input variable names differ from those in the fuel element model above. Both models will have idential input variable name when then are incorporated into fds5. |
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Two-dimensional temperature slice. This case also outputs tracer particles carried by the plume and by the inflow (not shown here). Australian grassland fuel. 200 m (100 grid cells) by 120 m (72 grid cells) domain (2 m horizontal grid resolution, 1.67 vertical resolution). Axes units are meters. Grass is ignited at upwind edge. The wind speed is uo = 3 m/s at a height of zo =2 m and depends on height according to u = (uo)(z/zo)^(1/7). Simulation time is 60 s (this takes about 1.2 cpu miniutes on a 3.8 GHz processor). Requires about 68 MB of memory. |
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Fire perimenter and smoke plume. Australian grassland fuel parameters. 300 m by 300 m horizontal domain (0.6 m grid resolution); 80 m tall domain (0.6 m cell near ground, stretches to 2.2 m at top). Computational grid is 180(x) by 180(y) by 72(z); over 2 million cells. Inert fuel break (dark color) surrounds grass. Axes units are meters. Grass is ignited at upwind edge in a time dependent manner (from center out to edges) to recreate field ignition procedures. The wind speed is uo = 7 m/s at a height of zo =2 m and depends on height according to u = (uo)(z/zo)^(1/7). Simulation time is 125 s (this takes about 9.6 cpu hours on a 3.8 GHz processor). Requires about 1.2 GB of memory. |
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Fire perimeter and smoke plume. The domain is split between the two processors as bordered by the colored lines. Same fuel parameters, domain size, grid resolution as case above (input_fireC064_1grid.txt) but runs on two processors. Axes units are meters. Required 5.6 cpu hours on dual 3.8 GHz processor computer. For details on running with multiple processors see the FDS user guide. |
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Fire line and smoke plume is shown. Domain in 4 m (x) by 1.25 m (y) by 2.2 m (z) with 80 (x) by 25 (y) by 45 (z) grid cells. Horizontal grid resolution is 5 cm; vertical starts at 2.5 cm at bottom and stretches to 20 cm at top. The fire spread from left to right in zero ambient wind. Green rectangle shows were the pine needle bed is. The color should change from green to something darker to denote what has been burned. This capability will be added to Smokeview. Simulation time of 300 s required about 3 hours of cpu time on a 3.8 GHz processor;66 MB of memory were required. |