# Compressible OpenFOAM FSI tutorial

**URL:** <https://precice.discourse.group/t/compressible-openfoam-fsi-tutorial/2935>\
**Category:** Using preCICE\
**Tags:** openfoam, fsi, compressible\
**Created:** [April 28, 2026, 8:54am UTC](https://precice.discourse.group/t/compressible-openfoam-fsi-tutorial/2935 "2026-04-28T08:54:39Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![hconel](https://yyz2.discourse-cdn.com/free1/user_avatar/precice.discourse.group/hconel/32/2142_2.png) [@hconel](https://precice.discourse.group/u/hconel)\
**Post date:** [April 28, 2026, 8:54am UTC](https://precice.discourse.group/t/compressible-openfoam-fsi-tutorial/2935/1 "2026-04-28T08:54:39Z")

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Hi, it is mentioned in several documents that preCICE works with OpenFOAM’s both incompressible and compressible solvers. This sounds reasonable in theory since the only difference is in the force calculation and variable rho. However, my recent tests with rhoPimpleFoam yielded a dimensional mismatch error, which is consistent with some other users (such as [here](https://precice.discourse.group/t/coupling-openfoam-of-rhopimplefoam-with-calculix/2227)).

I looked up for a preCICE tutorial case utilizing rhoPimpleFoam but could not find it, so now I am trying to set up my own case to be published. I think the best candidate would be the perpendicular-flap case. That will also help debugging the code I believe.

Meanwhile, any ideas on the source of [this](https://precice.discourse.group/t/coupling-openfoam-of-rhopimplefoam-with-calculix/2227) error would be appreciated.

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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:** [September 9, 2026, 5:20pm UTC](https://precice.discourse.group/t/compressible-openfoam-fsi-tutorial/2935/2 "2026-09-09T17:20:46Z")

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Hi @hconel,

I just now managed to look deeper into these threads and the connected issue ([Force computation for compressible solvers uses `p` field · Issue #253 · precice/openfoam-adapter · GitHub](https://github.com/precice/openfoam-adapter/issues/253#issuecomment-5605866450)).

In case you were intending to write to [Different dimensions for dimensions Issue in FSI when turbulence model is used - OpenFOAM adapter · Issue #158 · precice/openfoam-adapter · GitHub](https://github.com/precice/openfoam-adapter/issues/158), that issue has been fixed on `develop` and it will land on `v1.4.0`. I have been extremely slow on releasing a new version - a lot is going on here lately, on different fronts.

As I wrote in #253:

There are users that have used `rhoPimpleFoam` or other compressible solvers. For example, see [this blast/fence configuration coupling pimpleFoam to OpenRadioss](https://github.com/elisa-santoro/openradioss-cases/blob/master/blast-problem-coupled-1n5bar-M20-rubberWall/case2-100mmWall/fluid-openfoam/system/controlDict). A long time ago, others [coupled blastFoam](https://github.com/synthetik-technologies/blastfoam/blob/master/tutorials/preCICE/flap/README.md).

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<div class="post-metadata">

**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:** [September 14, 2026, 2:55pm UTC](https://precice.discourse.group/t/compressible-openfoam-fsi-tutorial/2935/3 "2026-09-14T14:55:35Z")

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v1.4.0 is out and it fixes the `Different dimensions` runtime error:

> **[Release v1.4.0 · precice/openfoam-adapter](https://github.com/precice/openfoam-adapter/releases/tag/v1.4.0)**
>
> The release v1.4.0 of the OpenFOAM-preCICE adapter brings a few new features that prepare the adapter for larger changes in future releases, and fixes some long-standing issues, mainly related to c...