WIND in PyroSim

FDS version 6.6.0 added a new WIND namelist to describe wind and atmospheric conditions. Support for WIND is scheduled to be included in the next release of PyroSim. This post demonstrates a short-term work around for this data.

The new WIND namelist is described in the FDS User Guide, Chapter 10 – Atmospheric Effects and Wind. The FDS User Guide describes the wind_example.fds input file:

The computational domain is a flat landscape that is 1 km by 1 km by 100 m high. There are various rectangular blocks scattered about to represent buildings. The wind speed varies with height as shown in the first plot of Fig. 10.1. The wind also turns a full 360◦ in 50 s, starting and ending in the westerly direction (270◦). This turn of the wind is not realistic, but this case is intended to test the ramp and mean forcing functionality.

Figure 1 shows the geometry of the problem. The wind initially blows from left to right.

Figure 1: Geometry of wind example.
Figure 1: Geometry of wind example. The wind blows from the side boundaries.

To add the WIND parameters to PyroSim, copy the WIND (and associated RAMP) records and paste them into the Additional Records section, Figure 2. In this example, we have also included the VENT records that refer to the WIND in Additional Records. This just keeps everything in one location.

Figure 2: Additional Records section for WIND
Figure 2: Additional Records section for WIND

The remainder of the FDS file was imported into PyroSim. To ensure correct display, some OBST records were edited so that the coordinates were ordered min to max.

At 30 seconds, the wind has swirled around the obstructions, as shown in Figure 3.

Figure 3: Wind vectors at 30 seconds.

You can download the PyroSim input file here:

wind_example.psm

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