ANSYS-Fluent Tutorial

How to setup ANSYS (Fluent).

To use ANSYS (Fluent) on VPAC's HPC systems you will need to login with X11 forwarding enabled. On Linux or MacOS systems this is as simple as ssh -X [username]

VPAC has a license for ANSYS Academic Research (5 tasks) and ANSYS Academic Research HPC (per core) with 300 tasks. The aa_r license enables 5 concurrent fluent jobs each with up to 4 cores; beyond that and in aggregate, an additional 300 cores can be used. For clarity if there are 5 jobs with 4 cores each, the other 300 licenses are blocked from use and a 6th fluent job cannot launch.

If you are using MS-Windows you can follow these instructions for setting up X11 Windows Forwarding.

Once you are logged in you will need to run a GUI license manager. To initiate this please run the following:

  • $ module load ansys
  • $ /usr/local/ansys/shared_files/licensing/lic_admin/anslic_admin

A GUI will start; please follow these commands.

  • * Choose "Set license preferences for "
  • * Choose the version you wish to use, and click "Ok"
  • * Choose "Use Academic Licenses"
  • * Click "Ok"
  • * Choose the "File" Menu and then "Exit"

Now you can use Fluent.

Note: When reserving licenses from Moab, please use the following as an example:

For a 16 processor job:

#PBS -W x=GRES:aa_r+1%aa_r_hpc+12

For a 4 processor job:

#PBS -W x=GRES:aa_r+1

For the first 4 processors you only need to ask for aa_r+1, for every additional processor over 4 you need to ask for a single aa_r_hpc license as well.

Note with Fluent it is best to run with 16 or more cores with a maximum of 128.

An example job for 64 or 128 cores would look like this

#PBS -l nodes=64
# Select 128 processors
# PBS -l nodes=128
#PBS -l walltime=15:10:00
#PBS -o ansystestjob.txt
# next line is a phrase:
echo The Working directory is $PBS_O_WORKDIR
# change the working dir
#PBS -W x=GRES:aa_r+1%aa_r_hpc+60
# For 128 processors
# PBS -W x=GRES:aa_r+1%aa_r_hpc+124
module load ansys/145
fluent 3ddp -g -ssh -pinfiniband -mpi=pcmpi -t128 -cnf=$PBS_NODEFILE -i fluent_journal_file.jou

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