# FSI\_How do fluid solvers and solid solvers map data if the interfaces don't match

**URL:** <https://precice.discourse.group/t/fsi-how-do-fluid-solvers-and-solid-solvers-map-data-if-the-interfaces-dont-match/1290>\
**Category:** Using preCICE\
**Tags:** openfoam, data-mapping, calculix\
**Created:** [February 2, 2023, 8:37am UTC](https://precice.discourse.group/t/fsi-how-do-fluid-solvers-and-solid-solvers-map-data-if-the-interfaces-dont-match/1290 "2023-02-02T08:37:17Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![zyx](https://avatars.discourse-cdn.com/v4/letter/z/6a8cbe/32.png) [@zyx](https://precice.discourse.group/u/zyx)\
**Post date:** [February 2, 2023, 8:37am UTC](https://precice.discourse.group/t/fsi-how-do-fluid-solvers-and-solid-solvers-map-data-if-the-interfaces-dont-match/1290/1 "2023-02-02T08:37:17Z")

</div>

In the perpendicular-flap case, modify the size of the fluid-openfoam board, but not the caculix model. Is this mapping correct? For example, double the height of the flap in fluid openfoam without modifying the caculix model, can prececi exchange data? Is the mapped data correct?  
Thank you very much! 😊

---

<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:** [February 3, 2023, 8:34am UTC](https://precice.discourse.group/t/fsi-how-do-fluid-solvers-and-solid-solvers-map-data-if-the-interfaces-dont-match/1290/2 "2023-02-03T08:34:02Z")

</div>

While the mapping handles cases where the two boundaries overlap or have gaps, they need to model the same geometry. If you have the two boundaries in different axes or they have very different lengths, then the mapping will do its best, but it will not be correct. In some rare cases, it may give seamingly reasonable results by sheer luck, but it will still not be correct.

---

<div class="post-metadata">

**Author:** ![zyx](https://avatars.discourse-cdn.com/v4/letter/z/6a8cbe/32.png) [@zyx](https://precice.discourse.group/u/zyx)\
**Post date:** [February 4, 2023, 12:35am UTC](https://precice.discourse.group/t/fsi-how-do-fluid-solvers-and-solid-solvers-map-data-if-the-interfaces-dont-match/1290/3 "2023-02-04T00:35:33Z")

</div>

Thank you very much for your reply!  
Would you please recommend an open source fluid-structure coupling meshing software that is easy to use？

---

<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:** [February 6, 2023, 4:18pm UTC](https://precice.discourse.group/t/fsi-how-do-fluid-solvers-and-solid-solvers-map-data-if-the-interfaces-dont-match/1290/4 "2023-02-06T16:18:23Z")

</div>

Unfortunately, this is totally out of my expertise, as I typically don’t work on applications… :-/

But it would be a great question for [Non-preCICE - preCICE Forum on Discourse](https://precice.discourse.group/c/non-precice/10)

---

<div class="post-metadata">

**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/precice/original/1X/67d2a5fa6f80e597e2267ff17fa8c1673cd11caa.svg) [@system](https://precice.discourse.group/u/system)\
**Post date:** [February 9, 2023, 4:19pm UTC](https://precice.discourse.group/t/fsi-how-do-fluid-solvers-and-solid-solvers-map-data-if-the-interfaces-dont-match/1290/5 "2023-02-09T16:19:21Z")

</div>

This topic was automatically closed 3 days after the last reply. New replies are no longer allowed.