# Coupling for Finite Differences, Incompressible Code, and Finite-Volume, Compressible Code

**URL:** <https://precice.discourse.group/t/coupling-for-finite-differences-incompressible-code-and-finite-volume-compressible-code/1752>\
**Category:** Is preCICE for me?\
**Created:** [January 19, 2024, 1:26pm UTC](https://precice.discourse.group/t/coupling-for-finite-differences-incompressible-code-and-finite-volume-compressible-code/1752 "2024-01-19T13:26:41Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Mahsaft](https://yyz2.discourse-cdn.com/free1/user_avatar/precice.discourse.group/mahsaft/32/2151_2.png) [@Mahsaft](https://precice.discourse.group/u/Mahsaft)\
**Post date:** [January 19, 2024, 1:26pm UTC](https://precice.discourse.group/t/coupling-for-finite-differences-incompressible-code-and-finite-volume-compressible-code/1752/1 "2024-01-19T13:26:41Z")

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Hi preCICE Team,

For my project, I need to couple a finite differences, incompressible code with a finite-volume, compressible code. I noticed that preCICE is mostly used for FSI applications. Is it possible to use it for a two-way coupling of fluid-fluid (finite differences, incompressible code, and finite-volume, compressible code)?

Thank you in advance for your help. ☺

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**Author:** ![Makis](https://yyz2.discourse-cdn.com/free1/user_avatar/precice.discourse.group/makis/32/25_2.png) [@Makis](https://precice.discourse.group/u/Makis)\
**Post date:** [January 21, 2024, 10:33pm UTC](https://precice.discourse.group/t/coupling-for-finite-differences-incompressible-code-and-finite-volume-compressible-code/1752/2 "2024-01-21T22:33:42Z")

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Technically, this is possible. But mathematically, it makes limited sense to couple an incompressible with a compressible fluid solver. If you have such an application, you would still need to somehow convert from the compressible description to the incompressible (e.g., pressure dimensions). This conversion is something you could do in one of your codes, before writing / after reading.

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**Author:** ![Mahsaft](https://yyz2.discourse-cdn.com/free1/user_avatar/precice.discourse.group/mahsaft/32/2151_2.png) [@Mahsaft](https://precice.discourse.group/u/Mahsaft)\
**Post date:** [February 1, 2024, 12:19am UTC](https://precice.discourse.group/t/coupling-for-finite-differences-incompressible-code-and-finite-volume-compressible-code/1752/3 "2024-02-01T00:19:57Z")

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Thank you for the clarification. 🙂  
Currently, we are developing a script to compute density for our compressible code based on the incompressible one. Setting that aside, could you please confirm if perCICE can couple a finite volume solver with a finite difference code? Thank you.

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**Author:** ![DavidSCN](https://avatars.discourse-cdn.com/v4/letter/d/c37758/32.png) [@DavidSCN](https://precice.discourse.group/u/DavidSCN)\
**Post date:** [February 1, 2024, 7:10am UTC](https://precice.discourse.group/t/coupling-for-finite-differences-incompressible-code-and-finite-volume-compressible-code/1752/4 "2024-02-01T07:10:11Z")

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> [@Mahsaft](#):
>
> Setting that aside, could you please confirm if perCICE can couple a finite volume solver with a finite difference code?

Yes, that’s possible. preCICE has no notion of your internal discretizations.

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**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/precice/original/1X/67d2a5fa6f80e597e2267ff17fa8c1673cd11caa.svg) [@system](https://precice.discourse.group/u/system)\
**Post date:** [February 5, 2024, 4:07pm UTC](https://precice.discourse.group/t/coupling-for-finite-differences-incompressible-code-and-finite-volume-compressible-code/1752/5 "2024-02-05T16:07:44Z")

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