Running an OpenFOAM Motorbike Simulation on Qarnot HPC

Introduction

This tutorial will guide you through launching an OpenFOAM simulation on the Qarnot HPC platform. You'll run a motorbike aerodynamics case, which is a standard OpenFOAM example that simulates airflow around a motorbike.

By the end of this tutorial, you will:

Upload the required input files to the Qarnot platform
Configure and launch an OpenFOAM simulation
Set up periodic snapshots to monitor progress
Access and verify your simulation results

Prerequisites

Before starting this tutorial, make sure you have a Qarnot account with access to the HPC platform

Step 1: Prepare your input files

Download motorbike case (Open Foam foundation 11, for Open Foam 2412)
Extract the downloaded archive to a local folder

This will create a folder containing all the necessary OpenFOAM configuration files for the motorbike simulation

Step 2: Creating a new simulation task

Log in to your Qarnot HPC platform account
Navigate to the "Create New Task" section
Start configuring your simulation by filling in the basic information:

Software Configuration

In the Software section, enter the following details:

Name: Test-Motorbike
Software: OpenFOAM
Version: 11 (resp. 2412)

Step 3: Configure input data and command

In the Input section:

Click on "Upload local asset to create new cloud folder"
Select the MOTORBIKE folder you extracted earlier
Ensure "Use it for storing results" is checked
Command: Allrun

Step 4: Configure hardware resources

In the Hardware section:

Pricing plan: Flex
Hardware: Select one of the available Xeon options (recommended for better availability)
Nodes count: 1
Max Wall time: 48 hours (the simulation should complete in around 30 minutes, but this gives you a buffer)

Note: While AMD processors in the single core section are available, they are less common in production and might result in longer queue times.

Step 5: Configure snapshot settings

Expand the Advanced Settings section
Set the snapshot parameters:
- Interval: 90 seconds (periodic snapshots will be taken every 90 seconds)
- Optionally, configure filtering options:
  - Whitelist: Enter regular expressions to specify which files to include (e.g., .*\.log to only include log files)
  - Blacklist: Enter regular expressions to specify which files to exclude (e.g., .*\.tmp to exclude temporary files)
- Leave the remaining advanced settings at their default values

Step 6: Launch the simulation

Review all your configurations
Click the Start button to launch your simulation
You'll be redirected to the main page, and can then open the simulation just launched. It will bring you to the simulation monitoring page where you can track the progress of your run

Step 9: Access and verify results

Once the simulation completes (approximately 30 minutes on Xeon processors), the status will change to "Success"
Navigate to your cloud storage folder to access the results
You should see new files and directories created by the simulation
Specifically check for:
- The share directory
- Inside the share directory, locate the log.foamRun file
- Verify that the file ends with the following output, confirming a successful simulation:

Time = 500s
smoothSolver:  Solving for Ux, Initial residual = 0.000179671, Final residual = 1.76545e-05, No Iterations 2
smoothSolver:  Solving for Uy, Initial residual = 0.00390968, Final residual = 0.000383084, No Iterations 2
smoothSolver:  Solving for Uz, Initial residual = 0.00355162, Final residual = 0.0003481, No Iterations 2
GAMG:  Solving for p, Initial residual = 0.00811676, Final residual = 0.000338057, No Iterations 2
time step continuity errors : sum local = 3.99326e-05, global = -4.36312e-07, cumulative = 0.000206543
smoothSolver:  Solving for nuTilda, Initial residual = 0.000250288, Final residual = 7.44096e-06, No Iterations 3
ExecutionTime = 1100.13 s  ClockTime = 1101 s
streamlines streamlines write:
    Seeded 20 particles
    Sampled 18835 locations
forceCoeffs forces write:
    Cm    = 0.18873
    Cd    = 0.46329
    Cl    = 0.0716145
    Cl(f) = 0.224537
    Cl(r) = -0.152922
End
Finalising parallel run

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Conclusion

Congratulations! You have successfully launched your first OpenFOAM simulation task on the Qarnot HPC platform. You've learned how to:

Configure an OpenFOAM simulation
Set up periodic snapshots
Monitor a running simulation
Verify simulation results

What's next?

Now that you've completed your first simulation, you might want to:

Experiment with different hardware configurations to optimize performance
Try running larger simulations with multiple nodes
Explore different snapshot filtering options to focus on specific result files
Visualize your simulation results using ParaView or other visualization tools

Troubleshooting

If your simulation doesn't complete successfully:

Check the log files for error messages
Verify that your input files were uploaded correctly
Ensure that the "Allrun" script has executable permissions
Try increasing the wall time if your simulation is timing out
Contact Qarnot support if you continue to experience issues

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