CFD Simulations in SimScale
- Connor Hawkins
This section is going to explain how to use SimScale for computational fluid dynamics (CFD) simulations of a solar car. It will cover the basics of a simple, steady-state case and discuss some of the more advanced settings, but will assume some knowledge of fluids. This information has been compiled from what I was taught by more experienced members, my own research, and my experiences while simulating MSXIV.
If you want to read about CFD simulations in ANSYS Fluent, there’s this page from the development of MSXII. That page is a great resource in general as it also discusses the workflow of CFD simulations and explains settings concisely.
As of the time of writing, our results have not been validated. I will update this section when we have physical data and measurements from MSXIV but until then keep this in mind.
What is SimScale?
SimScale is a web-based simulation platform, which allows the user to simulate how their CADed design would behave instead of having to build a prototype of their design and test it. What sets SimScale apart from the other simulation programs (like ANSYS) is that SimScale takes advantage of cloud computing. CFD simulations are usually very computationally demanding, which can take days to run on an average computer. Cloud computing means users can send their simulations to SimScale, who use really powerful computers to finish moderately large simulations in a couple of hours, and send the results back. There are also several other benefits to using SimScale, such as having a simple and intuitive user interface, access to help from simulation experts, and educational tools to learn about simulation theory.
To use SimScale, go to simscale.com:
In the top bar, there is a drop-down menu for Learning. Go here for tutorials, webinars, and documentation. In the top right, you can log in or sign up for a new account. Free accounts (called community accounts) are limited to 16 computing cores and 3,000 core hours. This account type is great for personal accounts where you can learn how to use SimScale and test things out.
Remember that community accounts can only create public projects. This lets any other member on SimScale see your projects. If you are working on a confidential project (or just prefer to keep your project private), then you may need to pay for a more professional account or use a different simulation software.
The team was sponsored during the design of MSXIV, which granted the team an account with a 32 core limit, over 40,000 core hours, and private projects. That may seem like an excessive number of core hours, especially when compared to a community account, however CFD simulations can easily consume that many hours. In the future, I would recommend planning core hour use and reserving a portion of the team account’s core hours for advanced simulations (Cross winds, rotating wheels, ventilation, etc) if these results are desired.
I’ll divide the simulation workflow into 4 subsections, each one must be completed before moving on to the next one: