ANSYS products


On March 29 2021 there was a change in the ansys license server. If you get an error like


Capability XXXXX YYYYYY ZZZZZZ does not exist in the ANSYS licensing pool.
No specified user license preferences match available products in the specified license path:
    ANSYSLI_SERVERS: ...........
    FLEXlm Servers:  ...........

*** ERROR - ANSYS license not available.

you need to reset the license settings to the default.


General Infos

ANSYS is a suite of software aimed at engineering simulation in many different fields. DTU provides the installation files, and the software is also installed in the HPC cluster. However the usage of ANSYS at DTU is subject to a quite strict license agreement, so please be sure that you are allowed to run the software, before submitting jobs to the HPC. Some more details and link to useful informations can be found at the ANSYS page on the gbar website.

Starting the different ansys products

The suite comes with a lot of different programs, and in linux those needs to be started from the command line, and the commands can be not so easy to find. Here we list the most common ones. For simplicty, we define the as BASENAME the common part of the PATH, that depends on the specific ansys version. For version 2020R1:


All the commands start the Graphical User Interface (GUI) for the corresponding program. This is fine for preparing/analysing models, and for short runs.  Production runs are supposed to be run as batch jobs, instead, and no GUI is allowed when doing that


Fluent is ANSYS’s fluid simulation package. To run in batch mode, have a look at this page. The command to start fluent’s GUI is



cfx is ANSYS’s, computational fluid dynamics software for turbomachinery applications. Like for the fluent package, io run it in batch mode, have a look at this page. The command to start cfx’s GUI is



Ansys Workbench is a graphical modeling environment, a gateway to other Ansys products. It is suitable for modeling and  for short/small-scale runs. It can be scripted, and in principle also run in batch mode, but in our experience it does not allow to fine-tune the execution instructions for the other products that it starts to perform the different functions, therefore it is not recommended for batch job executions.

unset LC_CTYPE

Ansys Mechanical APDL Product Launcher

As the name says, it is the graphical launcher for the Mechanical APDL product. The command to start it is:


It is meant for interactive/graphical runs only. It can potentially be used to run jobs in parallel/with GPUs locally and remotely, but it require a level on integration with the cluster environment that is not present, at the moment. For the batch mode, the command to directly start the APDL interpreter without GUI is


This can be used in batch-jobs natively.


Chemkin-pro is ansys product to simulate the effects of chemistry in  system. To run it on the cluster, one needs first to load specific environment settings with the command

source $BASENAME//v201/reaction/chemkinpro.linuxx8664/bin/chemkinpro_setup.ksh 

then the command to start chemkin-pro becomes available:




or others, depending on the specific product one needs. This step gives access also to all the other sub-programs of the suite. Scripting/command line usage, is possible, but our experience is very very limited at the moment. 

Changing the license settings (for ansys 2020R1 and older versions)

The usage of all of the ansys products is subject to strict licensing conditions, that can be found here. Apart from this, by default ansys uses the Academic Teaching license, that have some limitations (maximum number of cores per job and limitations on the size of the model, among others). These settings can be changed (for all the runs on the cluster started after the change) with ansys’ license tool, that can be started with the command:


Remember that the total number of license is limited, try not to use licenses that are not needed. Because the license availability is checked only once whe the program starts, one can in principle set the licence on a per-run basis.