Did you know you can output summaries, such as mass flow summary, force summary etc. at your desired time interval independently of the DTF file save frequency? This option not only saves time but also memory and disk space. Using a “Special DTF Update” command, you can activate the summary output frequency at your choice of iteration interval (for steady state cases) or time steps (for transient cases).

This is a very useful tool, especially when you are running a large transient model (3D case with more than 1 million cells for example) and you need the output summary every time step. Indeed, if you ask to save DTF files every time step, it will take time to write and save the DTF files and also fill up the hard disk drive very fast. So you would have to manually clean-up the DTF files. Fortunately, you can avoid these issues by using the “special DTF update” command for summary output frequency.

The command syntax is:  SUMMARY_OUTPUT_FREQ int 1 Frequency
- int: means that the input for this command in an integer
- 1: means that the command SUMMARY_OUTPUT_FREQ requires exactly 1 input (the frequency in this case)
- Frequency: time step interval or frequency to write summary in output file

Consider a transient case running for 1000 time steps (see figure 1) where DTF files need to be written and saved every 100 time steps (see figure 2).

Figure 1. Input for number of time steps

Figure 2. Input for DTF write/save frequency

If you need to write the summary output every 10 time steps, simply write the command in the “Special DTF Update”, as shown in figure 3.

Figure 3. Special DTF update feature in CFD-ACE-GUI

Click OK and save the DTF file. Submit to solver.

Were the simulation steady, the summary output would be written every 10 iterations.

If you have any questions about this feature or would like us to discuss some other topic in the future, please let us know.

Regards,
Kartik Shah
ESI CFD Support Team