General

General

How to create and execute a FLUENT journal file?

    • FAQFAQ
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      In Fluent, a journal is a file that contains a list of Fluent instructions for the setup, the run and the post-processing of a calculation. It is written with TUI (Text User Interface), scheme commands or GUI (Graphical User Interface) actions. Once this file has been created, it can be used to run the solver automatically. This can be very useful in case the same setup is repeated on different geometries, etc. In this solution, we will see how to create a journal file and how to use it. 1) Journal File creation: The list of instructions can be written within a text editor. The interactive TUI inside Fluent helps: click on the keyboard Enter button to see all the available menus, click on letter “q” to come back to the previous menu. This can lead to this kind of journal file for example (the semicolon (;) is used to include comments): ; example.jou ; starting command : fluent 3ddp -i example.jou -g >> output.txt & /file/read-case-data “tank-flush.gz” ; read the case and data files /solve/initialize/hyb-initialization ; initialization /solve/dual-time-iterate 10 10 ; iterate with the transient solver /file/write-case-data “final.gz” ok exit yes Fluent can also record all what is done during the interactive setup through File > Write > Start Journal. The setup is saved with GUI language in the journal file. But it is recommended to create journal file with the TUI (using TUI commands or scheme commands) and not through de GUI, as GUI structure may changes from one version to another one. Note that in this recorded file, all the lines will start with (cx-gui-do ….) which represents all the click on the GUI. Moreover, for information, TUI instructions are far more explanatory than GUI instructions in a journal file. 2) Journal file execution: Once your journal has been created (either from scratch within a text editor or using the recording mode in Fluent) you can run it. There are two ways to run a journal file : In interactive mode: File > Read > Journal : this will replay the instructions given in the journal file In batch mode: [usual fluent starting command] -i journal_file.jou & For example: fluent 3ddp -t4 -i example.jou -g >> transcript.out This command will run Fluent in 3d double precision (dp), in parallel on 4 procs (-t4) using the example.jou journal file (-i), in batch (-g) and save the output to the transcript.out file (>>).