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ANSYS Fluent

ANSYS Fluent is the industry-leading fluid simulation software known for its advanced physics modeling capabilities and industry leading accuracy

Using ANSYS Fluent interactive
(Graphical User Interface)

ANSYS Fluent in Umbrella On Demdand Use your browser to connect to Umbrella On Demand

Using ANSYS Fluent in SLURM batch jobs
(Command Line Interface)

Test ANSYS Fluent

Load the module(s)

[user@umbrella]$ module purge
[user@umbrella]$ module load foss/2025a # or intel/2024a for -mpi=intel)
[user@umbrella]$ module load ANSYS/2025R2

Check ANSYS Fluent:

[user@umbrella]$ fluent 3ddp -g -t2 -mpitest -mpi=openmpi

FLUENT MPI test started ... 

Ping pong latency test ...
ping..pong..latency(usec)...count..host
-------------------------------------------------------------
0.....1.....0.29906.........10000..0:tue-login002.icts.tue.nl
1.....0.....0.296366........10000..1:tue-login002.icts.tue.nl

Ping pong bandwidth test ...
ping..pong..bandwidth(MB)...count.msg-size(MB)..host
-------------------------------------------------------------
0.....1.....6049.28.........10....4.............0:tue-login002.icts.tue.nl
1.....0.....5543.97.........10....4.............1:tue-login002.icts.tue.nl

Global reduction test ...
MPI-function...time-per-msg(usec)..count...total-time(sec)..
-------------------------------------------------------------
Bcast..........0.194028............5000....0.000970142......
Reduce.........0.22126.............5000....0.0011063........
Barier.........0.308314............5000....0.00154157.......

FLUENT MPI test done.

ANSYS Fluent SLURM sbatch jobscript example using OpenMPI on 1 Node

#!/bin/bash
#
#SBATCH --job-name=test_ansys
#SBATCH --output=test_ansys-%j.log
#SBATCH --partition=tue.default.q
#SBATCH --nodes=1
#SBATCH --ntasks-per-node=8
#SBATCH --cpus-per-task=1
#SBATCH --mem-per-cpu=2gb
#SBATCH --time=00:05:00

module purge
module load foss/2025a
module load ANSYS/2025R2

fluent 3ddp -g -t${SLURM_NTASKS} -mpitest -mpi=openmpi

ANSYS Fluent SLURM sbatch jobscript example using OpenMPI on 2 Nodes

#!/bin/bash
#
#SBATCH --job-name=test_ansys
#SBATCH --output=test_ansys-%j.log
#SBATCH --partition=tue.default.q
#SBATCH --nodes=2
#SBATCH --ntasks-per-node=8
#SBATCH --cpus-per-task=1
#SBATCH --mem-per-cpu=2gb
#SBATCH --time=00:05:00

module purge
module load foss/2025a
module load ANSYS/2025R2

JOB_NODES="$(scontrol show hostnames)"
JOB_NODES=$(echo ${JOB_NODES} | tr ' ' ',')

fluent 3ddp -g -cnf=${JOB_NODES} -t${SLURM_NTASKS} -mpitest -mpi=openmpi

Troubleshooting

Unable to spawn node: license not available.

If you find the following message in the job's log files

  • Unable to spawn node: license not available.

then either of two situations applies:

  • All licenses are currently in use. Try again later; perhaps some licenses have become free, in which case your job will run.
  • You don't have access to the license. Contact the license owner to request access. The respective license owner can often be looked up in the TOPdesk self-service portal, in the form of a knowledge item.