FLUENT is a computational fluid dynamics package from Fluent, Inc. that is used to model fluid flow and heat transfer in complex geometries. Gambit 2.2.30 (a mesh generator) is installed with Fluent 6.3.26 where appropriate.
General Notes for Running Fluent at CTC
- Fluent's serial and parallel capabilites are available to users.
- Fluent can be run either in batch, or interactively using its graphical user interface (GUI), according to the type of node.
- In the Collaboratory (651 Rhodes Hall), users have full interactive access to Fluent and Gambit.
- On the batch nodes, full interactive access to Fluent is possible while a batch job is active (see below).
- On the login nodes, limited interactive access is available for visualization, data analysis, help-file reference, and UDF compilation, in accordance with CTC's policy on login node use.
- Fluent (and Gambit, if installed) is normally run in command line mode on batch machines.
- First, a Fluent input file should be created, listing the commands that are to be carried out. The commands are identical to the commands that are typed into the console when running Fluent in the normal graphics mode (see Fluent help for more information).
- This input file should end with the command "exit y". The "y" is recommended because Fluent often asks the user if it is OK to discard the case or data file before exiting. If this query goes unanswered, the job will not end.
- Users may wish to append "y" or "n" to other commands in the input file, anticipating similar questions that Fluent might ask. Examples: "file start-trans journalfile.txt y" and "wd output.dat y". Explanation: when a file with a matching name is found on the disk, Fluent will ask if it is OK to overwrite it. If no "y" or "n" answer is provided, Fluent will use up subsequent commands in the input file looking for this "y" or "n". This will lead to unexpected behavior.
- Before running Fluent, the user's batch script must execute the setup file by issuing the command:
call setup_fluent.bat
This sets the appropriate path and other environment variables.
- It is possible to run Fluent interactively on the batch machines, if the need arises.
- Remote Desktop Connection (RDC) can be used to log in to any machine that has been assigned to a batch job. Fluent's full graphical interface is then started by typing "setup_fluent" followed by "fluent", along with any options of the user's choosing, including parallel options. This allows complete workstation-style access to parallel Fluent, similar to what is found in the Collaboratory.
- RDC will not let a user interact with a running Fluent session that was already started via a batch script as outlined above. However, if a batch job fails, then the failed script can be re-run interactively by typing the name of the batch script. This technique—which also works in the Collaboratory—is useful for diagnosing problems with a batch script.
- For general batch submissions, the scripted, non-interactive method of running Fluent is normally preferred, due to the unpredictable start times of batch jobs.
- Some software products from Fluent, Inc. may encounter problems if directory names or files contain blank spaces. Therefore, do not select such names for files and directories with which Fluent will interact. (Reference: Fluent Installation Guide)
Fluent Sample Batch Command Files
- Batch files differ slightly for serial, multi-cpu, and parallel cluster jobs. Here are sample files which can be modified as required, along with corresponding explanation files.
Serial jobs:
sample batch file
in-depth explanation of the sample batch file
Multi-cpu jobs:
sample batch file
in-depth explanation of the sample batch file
Parallel cluster jobs:
sample batch file
in-depth explanation of the sample batch file
file used by the sample batch file
- Here is a list of variables that must be edited in the scripts for serial and multi-cpu jobs:
|
Variable |
Description |
Example |
|
FLUENT_VERSION |
the Fluent version that the user wants to run (2d, 3d, 2ddp, 3ddp) |
set FLUENT_VERSION=2ddp |
|
ROOTDIR |
the H: directory where the Fluent script file (IN_FILE) and any necessary data files exist. Output will also be written here. |
set ROOTDIR= H:\Users\joeuser\fluentjob |
|
IN_FILE |
the name of the Fluent script file
|
set IN_FILE=scriptfile |
|
OUT_FILE_n |
the nth output file from Fluent |
set OUT_FILE_1=outputfile |
- Here is an additional variable for multi-cpu jobs:
|
Variable |
Description |
Example |
|
PROCS_PER_BOX |
sets the number of processors to use |
set PROCS_PER_BOX=2 |
Fluent Documentation
Documentation for Fluent is available, but not by using the Help menu in the Fluent application. On the machines in the Collaboratory, select it from the Windows XP Start menu. On CTC login nodes (using Remote Desktop Connection) or from anywhere, access it from H:\CTC Tools with the following command:
help_fluent
Users can invoke the help found in H:\CTC Tools in either of these two ways:
- Browse the H:\CTC Tools folder and double click on the help filename.
- From a command prompt (H:\CTC Tools must be in the path), enter the help filename as a command.
Included in the Fluent documentation is information on how to run the tutorials. The files that go along with these exercises are available in the folder H:\CTC Tools\SoftwareDocs\Fluent\version-6.3\tutfiles.
Fluent Web Pages
Fluent, Inc. home page www.fluent.com
Fluent product page www.fluent.com/software/fluent
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