Ansys Fluent

Ansys Fluent is a computational fluid dynamics code that is available on Joule 3.0. There are a limited number of licenses available for Ansys Fluent. The status of the license can be checked from any login node using this command:

flstat

Running Fluent

To run Ansys Fluent in a graphical mode, first open a terminal inside a Cap Client GUI Session. Next, copy the /nfs/apps/Submission/srun_fluent file to the current working directory. The version of Ansys Fluent can be changed by updating this line in the file:

module load ansys/24.1

After the appropriate changes are made, the srun command can be used to start Ansys Fluent in the GUI session.  For all Ansys Fluent submissions, the “-N” and “-n” flags should be set. As noted in the Hardware section, each Joule 3.0 computation node has 128 cores. To utilize all of the cores on a multi-node run, this example line can be used for a two node job:

srun --x11 -N2 -n256 srun_fluent

“-N2” specifies two nodes. The “-n256” requests 256 cores with 256 being a multiple of 128.

Here is an example of a job that uses 80 cores per node on a two node submission:

srun --x11 -N2 -n160 srun_fluent

Using less than the maximum of cores may provide a performance boost for job submissions with larger number of nodes.

When an Ansys Fluent run ends, the srun command will exit and return to a normal terminal prompt. 

Running Fluent on a Single Node

To run Ansys Fluent on a single node, use “-N1” to specify that a single node should be used. For a run that uses all of the cores on a single system, “-n128” should be used:

srun --x11 -N1 -n128 srun_fluent

For jobs that will use less than the maximum number cores, make sure the “-n” flag is less than 128. This example can be used to launch Ansys Fluent on 80 cores:

srun --x11 -N1 -n80 srun_fluent