Introduction

Elmer is an open source finite element software used to solve partial differential equations. It contains many models for computing many physics : fluid flows, structural mechanics, electromagnetics, heat transfers, acoustics, etc. Running your Elmer simulation on Qarnot is as easy as uploading your case and launching a script. Here’s a walk-through of the different steps.

Versions

The test case uses Elmer 9.0.

If you are interested in another version, please send us an email at qlab@qarnot.com.

Test case

Please ensure that you have created a Qarnot account here.

This test case is based on a lid-driven cavity basic example with a top velocity of 10m/s. You can download the case folder here, which contains the mesh and case setup files with a bash script to launch the Elmer commands. You should put it at the same folder level as the script to launch the calculation. Please note that it needs to be unzipped before it can be used on Qarnot.

Launching the case

Before starting a calculation with the Python SDK, a few steps are required:

• Retrieve the authentication token (here)
• Install Qarnot’s Python SDK (here)

Note: in addition to the Python SDK, Qarnot provides C# and Node.js SDKs and a Command Line.
Once everything is set up, the following script needs to be used to start the calculation.

Be sure you have copied your authentication token in the script (instead of <<<MY_SECRET_TOKEN>>>) to be able to launch the task on Qarnot.

elmer.py

To launch this script, simply copy the preceding code in a Python script, put at the same level as the cavity folder and execute python3 elmer.py & in your terminal.

Results

At any given time, you can monitor the status of your task on the general web interface Console. The following figure shows a successful Elmer demo simulation on Qarnot’s console.

You should also now have a result folder in the output bucket and on your computer containing all the numerical results. You can open case_t0001.vtu file (in the square folder) in Paraview or any other viewer. You can also use our Paraview Web payload to view the results online if needed.

Wrapping up

That’s it! If you have any questions, please contact qlab@qarnot.com and we will help you with pleasure!