# Using both external and internal volume in one design

**URL:** <https://www.simscale.com/forum/t/using-both-external-and-internal-volume-in-one-design/99582>\
**Category:** Fluid Flow / CFD\
**Created:** [December 17, 2024, 4:50pm UTC](https://www.simscale.com/forum/t/using-both-external-and-internal-volume-in-one-design/99582 "2024-12-17T16:50:01Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![igaviano](https://www.simscale.com/forum/user_avatar/www.simscale.com/igaviano/32/73967_2.png) [@igaviano](https://www.simscale.com/forum/u/igaviano)\
**Post date:** [December 17, 2024, 4:56pm UTC](https://www.simscale.com/forum/t/using-both-external-and-internal-volume-in-one-design/99582/2 "2024-12-17T16:56:59Z")

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Hi @Owura, thanks for posting on the forum and welcome to the SimScale Community 🤝

> [@Owura](#):
>
> I want to know whether the results i got is a true representation of the right thing i have done as i see some extreme temperatures I am not so convinced they might be true

Since your project is not shared with support, unfortunately we can’t pinpoint what the exact issue is - take a look **[here](https://www.simscale.com/forum/t/guide-to-clear-and-understandable-forum-posting/99461#:~:text=Important%3A%20If%20your%20project%20is%20private%20(common%20for%20Academic%20users)%2C%20ensure%20the%20%E2%80%9CShare%20with%20Support%E2%80%9D%20option%20is%20enabled.%20This%20allows%20the%20Support%20Team%20to%20access%20your%20project%20even%20if%20it%E2%80%99s%20not%20public%20(you%20can%20still%20post%20it%E2%80%99s%20URL))** to know how to share your project. However, from your description, this does sound like a divergence issue, in which case these resources might be helpful:

- **[How to Check Convergence of a CFD Simulation? | SimScale](https://www.simscale.com/knowledge-base/how-to-check-convergence-of-a-cfd-simulation/)**
- **[Divergence in Simulation: How to Tell When and Where? | SimScale](https://www.simscale.com/knowledge-base/divergence-simulation-knowledge-base/)**
- **[How to Check and Improve Mesh Quality | SimScale](https://www.simscale.com/knowledge-base/how-to-check-and-improve-mesh-quality/)**

I also often see these “extreme temperatures” appearing when there’s no channel for the heat to flow - for instance, if the domain’s walls are defined as “adiabatic”.

Hope this helps!

Cheers  
Igor

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