You can use a gas monitor region to make Flacs report the amount of fuel inside the defined region, for example a module, during a simulation.

Gas monitor region output

When you define a gas monitor region then the Flacs simulator will write a text file called rt<jobnr>.FUEL. The rt.FUEL file contains a number of columns showing different measures of the amount of fuel inside the defined volume. The meaning of the quantities is summarised at the beginning of the file; you can find additional information in the FLACS User’s Manual.

More than one gas monitor region

If you need to monitor more than one volume in the domain, or use line monitor regions, then you can add a monitor file to the scenario. You can either define the monitor regions in the CASD scenario menu, “Custom gas monitor regions” section, or using a text editor in a file called cs<jobnr>.MON. Monitor regions can be of type Line or Volume. Each gas monitor region must have a unique name <name>. Flacs writes overall output for all monitor objects to a text file with the name rt<jobnumber>.MON, and detailed output per monitor object to text files called rt<jobnumber>.MON.<name>. Flacs will accept a maximum of 100 monitor objects in the cs<jobnumber>.MON file.


Line monitors

You can use line monitors to measure fuel concentrations or pressure along a given straight line in the domain. Flacs requires the start and end position of the line and will divide it into a number (default 100) of segments of equal length. The simulator interpolates values at all intermediate points along the line based on the 3D data and writes them to the line monitor’s specific file. The general rt<jobnumber>.MON file, contains only basic output for the line monitor, for example the average or integral value over the length of the line.

Volume monitors

Use volume monitors to measure amounts of fuel inside a given volume in the domain. Specify the volume by two diagonally opposed corner points of an axis-aligned rectangular box. Flacs writes the results to the common rt<jobnumber>.MON file and to the monitor’s specific file, including several output variables, e.g. total amount of fuel (kg) and equivalent cloud sizes (m3).

Advanced topics covered in the user manual

You can find more details on line and volume monitors in the monitor file section.