Visualization Techniques

FDS results are visualized with Smokeview by displaying time dependant animations of particle flow, 2D slice contours, 2D vector slices, isosurfaces and surface boundary contours. Data at a particular time may also be visualized using 2D/3D contours and vector plots. Some examples are given below. Each example contains a still picture along with links to animation files in either real video, avi or mpeg formats.

• Touring
• 3D Smoke
• Particles
• 2D Slice Contours
• Vector Slices
• Isosurface (3D surface contours)
• Boundary Surface
• PLOT3D
• Other Examples

The touring option allows one to specify arbitrary paths or tours through or around a Smokeview scene. One may then view the scenario from the vantage point of an observer moving along one of these paths as in the animation to the left or alternatively, one may observe the motion along all paths from an external vantage point.

3D Smoke Animations

FDS computes soot density data on the entire 3D domain. It then converts and compresses this data to values used by Smokeview to draw a series of parallel, partially transparent planes. To generate 3D smoke, add SMOKE3D=.TRUE. to the &MISC line.

Particle Animations

FDS records the location and value of each particle at each selected time step. Particles are colored using criteria such as: temperature or whether they are water (sprinkler droplet). Particle animations are then drawn by Smokeview .

Slice Animations

FDS records slice file data within a rectangular array of grid points at each selected time step. Shaded contours plots are then drawn by Smokeview for simulation quantities such as temperature, gas velocity or heat release rate. To generate temperature slice contours at 1.5m along the Y axis, add the line &SLCF PBY-1.5 QUANTITY='TEMPERATURE' / to the input file.

Vector Slice Animations

FDS records slice file data within a rectangular array of grid points at each selected time step for temperature and three components of velocity. Vector plots are then colored Smokeview using simulation quantities such as temperature, gas velocity or heat release rate. Vector lengths and directions are drawn using the recorded velocity data. To generate an animated temperature vector slice contour plot at 1.5m along the Y axis, add the line &SLCF PBY=1.5 QUANTITY='TEMPERATURE' VECTOR=.TRUE. / to the input file.

Isosurface Animations

Isosurface files contain data defining desired surface locations using triangles. Isocontours are then drawn by Smokeview for simulation quantities such as temperature, mixture fraction or heat release rate per unit volume. To generate animated isosurface plots of mixture fraction add the line &ISOF QUANTITY='MIXTURE_FRACTION'/ to the input file.

Boundary Surface Animations

Boundary files contain simulation data recorded at the surface or boundary of interior obstacles and the exterior bounding surfaces of the simulation at each recorded time step. Shaded contours are drawn for quantities such as wall surface temperature, radiative flux, etc. To generate animated temperature boundary plots add the line &BNDF QUANTITY="WALL_TEMPERATURE" / to the input data file.

PLOT3D Visualizations

The previous visualization examples display time dependent data. PLOT3D data files on the other hand contain data stored at one particular time. Smokeview then visualizes PLOT3D data using 2D contours, 3D contours (or iso-contours), and flow vector plots as shown below. To generate PLOT3D files every 30 seconds of a simulation run, add the line &PL3D DTSAM=30.0 / to the input data file.

Visualizing a townhouse kitchen fire using PLOT3D data

2D contour plot of temperature at 300 seconds in a vertical plane through the fire center (stove). PLOT3D contours may be selected in any horizontal or vertical plane.
3D contour plot of temperature or sometimes called a level surface or iso-contour. The red surface represents the region in the townhouse where the gas temperature is 720 C (1300 F) .
Flow vector plot at 300 seconds in a vertical plane through the stairway center. The arrow's direction and length represents flow direction and velocity. The arrow's color (red = hot, blue = cool) represents temperature. Vector plots may selected for any horizontal or vertical plane.