Converge on Qarnot Cloud

Converge is an innovative computational fluid dynamics (CFD) software that eliminates the grid generation bottleneck from the simulation process through autonomous meshing. It accommodates complex moving geometries and features state-of-the-art physical models and a robust, fully coupled detailed chemistry solver so you can take on the hard CFD problems^*.

Here is a quick step by step walkthrough to guide you through the different steps of how to run a Converge test case on Qarnot, so follow along!

License

This software is proprietary, a license is necessary in order to use it. If you want to test this payload, please get in touch with our team: qlab@qarnot.com.

Version

The test use case uses Converge v3.0.16, release in January 2021.
If you are interested in another version, please send us an email at qlab@qarnot.com.

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

• Retrieve the authentication token
• Install Qarnot’s Python SDK

Note: in addition to the Python SDK, Qarnot provides C# and Node.js SDKs and a Command Line.

Prerequisites

Before launching the case, please ensure that the following prerequisites have been met.

• Create an account
• Retrieve the authentication token
• Install one of Qarnot’s SDK (Python) (Node.js) (C#) (Commande Line)

Test Case

This test case will show you how to launch a wind tunnel simulation on an airplane wing. The input files can be found in the following archive: wind_tunnel

Once you have downloaded everything, your working directory should look like this:

• wind_tunnel : contains case input files
• run-converge.py : launchs the computation on Qarnot (code found below)

Launching the Test Case

Once everything is set up, use the following script to launch the computation on Qarnot. Be sure to copy your authentication token in the script (instead of <<<MY_SECRET_TOKEN>>>) to be able to launch the task on Qarnot.

To launch this script, simply copy the following code in a Python script and execute python3 run-converge.py & in your terminal.

#!/usr/bin/env python3

# Import the Qarnot SDK
import qarnot

# Connect to the Qarnot platform
conn = qarnot.Connection(client_token='<<<MY_SECRET_TOKEN>>>')

# Create a task
task = conn.create_task('Hello World - Converge', 'converge', 1)

# Create a resource bucket and add input files
input_bucket = conn.create_bucket('converge-in')
input_bucket.sync_directory('wind_tunnel')

# Attach the bucket to the task
task.resources.append(input_bucket)

# Create a result bucket and attach it to the task
output_bucket = conn.create_bucket('converge-out')
task.results = output_bucket

# Take a snapshot every 10 seconds
task.snapshot(10)

# Submit the task to the API
task.run(output_dir='output')

Results

At any given time, you can monitor the status of your task on Tasq.

You should now have an output folder in your working directory on your computer and a converge_out bucket in Tasq containing all output files.

Most notably, the directory output/ contains the .h5 files that can be visualized on tools like Paraview to have something like this

Wrapping Up

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

Converge definition source^*