# Caculix diverged when solving multiphase FSI problem with compressibleInterDyMFoam **URL:** \ **Category:** Official adapters and tutorials\ **Tags:** openfoam, calculix, fsi\ **Created:** [January 11, 2023, 2:23am UTC](https://precice.discourse.group/t/caculix-diverged-when-solving-multiphase-fsi-problem-with-compressibleinterdymfoam/1271 "2023-01-11T02:23:09Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![zyx](https://avatars.discourse-cdn.com/v4/letter/z/6a8cbe/32.png) [@zyx](https://precice.discourse.group/u/zyx)\ **Post date:** [January 11, 2023, 2:23am UTC](https://precice.discourse.group/t/caculix-diverged-when-solving-multiphase-fsi-problem-with-compressibleinterdymfoam/1271/1 "2023-01-11T02:23:09Z")
![diverge_solide_1e-8ce](https://global.discourse-cdn.com/free1/uploads/precice/original/2X/e/ea4b30e6084492c12838e5e1149872a672c09935.png) ![1](https://global.discourse-cdn.com/free1/uploads/precice/original/2X/f/f4fd34e4feacd8f405d6a3e884a2374e75e2dffc.jpeg) ![2](https://global.discourse-cdn.com/free1/uploads/precice/original/2X/f/f31d7ada7f877dbc303d88abb75040c76f3acdb7.jpeg) Hello, everyone! I’m using precice and caculix for the first time. I modified the vertical-flap example by eliminating the incoming flow and adding a bubble near the elastic plate,hoping that bubble collapse would cause displacement and deformation of the plate. But the solid solution diverges at coupling. There is no displacement of the plate and only a small deformation in the result. I wonder if anyone understand why the solid solver diverges? Thank you very much! I uploaded pictures of caculix divergence and geometric pictures[precice-config.zip](https://precice.discourse.group/uploads/short-url/5TnRe07DigsjCqihqu3y8qFw0LR.zip) (996 Bytes) [solid-calculix.zip](https://precice.discourse.group/uploads/short-url/6SduSA7UsCxuinvMthH9p1LH5Dr.zip) (10.8 KB) I also uploaded the entire case. I hope you can help me see how to fix it ---
**Author:** ![zyx](https://avatars.discourse-cdn.com/v4/letter/z/6a8cbe/32.png) [@zyx](https://precice.discourse.group/u/zyx)\ **Post date:** [January 11, 2023, 2:25am UTC](https://precice.discourse.group/t/caculix-diverged-when-solving-multiphase-fsi-problem-with-compressibleinterdymfoam/1271/2 "2023-01-11T02:25:20Z")
[fluid-openfoam.zip](https://precice.discourse.group/uploads/short-url/oPpb16MfBFnnGszOHarVqxhDcex.zip) (165.9 KB) ---
**Author:** ![zyx](https://avatars.discourse-cdn.com/v4/letter/z/6a8cbe/32.png) [@zyx](https://precice.discourse.group/u/zyx)\ **Post date:** [January 11, 2023, 2:41am UTC](https://precice.discourse.group/t/caculix-diverged-when-solving-multiphase-fsi-problem-with-compressibleinterdymfoam/1271/3 "2023-01-11T02:41:53Z")
[log.openfoam.log](https://precice.discourse.group/uploads/short-url/zZjlnWjF1Yp5Njr9HvVSywWI313.log) (52.6 KB) This is the openfoam log file (omit the middle output otherwise the file is too big) ---
**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 13, 2023, 7:22am UTC](https://precice.discourse.group/t/caculix-diverged-when-solving-multiphase-fsi-problem-with-compressibleinterdymfoam/1271/4 "2023-01-13T07:22:39Z")
@zyx is the solid supposed to compress next to the bubble? Are the material parameters for the solid correct? If everything is correct, I could imagine that the adapter computes and couples the wrong force (unreasonably high) on the region of the interface touched by the bubble. Could you check the force acting on the plate? You could also use the preCICE exports: [Export configuration | preCICE - The Coupling Library](https://precice.org/configuration-export.html) ---
**Author:** ![zyx](https://avatars.discourse-cdn.com/v4/letter/z/6a8cbe/32.png) [@zyx](https://precice.discourse.group/u/zyx)\ **Post date:** [January 18, 2023, 2:48am UTC](https://precice.discourse.group/t/caculix-diverged-when-solving-multiphase-fsi-problem-with-compressibleinterdymfoam/1271/5 "2023-01-18T02:48:30Z")
Thank you very much for your reply! I want to see deflection in a two-dimensional plate rather than distortion. I set the plate as linear elastic material with an elastic modulus of 20MPa. Now that I’ve eliminated the subcycle, it can count more time steps. But all you see is the distortion of the plate.I uploaded the initial and divergent calculations. ![1](https://global.discourse-cdn.com/free1/uploads/precice/original/2X/6/63e2ecabed93a446967dc49539a6c7251b9c64ef.png) ![2](https://global.discourse-cdn.com/free1/uploads/precice/original/2X/2/2c887ef918e8ff70ce75eefdd9cf01dd473788e8.jpeg) I also think that the force on the board is acting too much, maybe the adapter calculated and coupled the wrong force. I was wondering if you have any good advices about the adapter calculation and coupling error? I appreciate very much ! ---
**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 18, 2023, 10:28am UTC](https://precice.discourse.group/t/caculix-diverged-when-solving-multiphase-fsi-problem-with-compressibleinterdymfoam/1271/6 "2023-01-18T10:28:57Z")
Let’s take a step back: are you running the official adapter, or a modified version? There are a few discussions already regarding this: [Multiphase FSI case with the OpenFOAM adapter - #2 by Makis](https://precice.discourse.group/t/multiphase-fsi-case-with-the-openfoam-adapter/1163/2) See also the `multiphase` tag: [Topics tagged multiphase](https://precice.discourse.group/tag/multiphase) ---
**Author:** ![zyx](https://avatars.discourse-cdn.com/v4/letter/z/6a8cbe/32.png) [@zyx](https://precice.discourse.group/u/zyx)\ **Post date:** [January 20, 2023, 1:49am UTC](https://precice.discourse.group/t/caculix-diverged-when-solving-multiphase-fsi-problem-with-compressibleinterdymfoam/1271/7 "2023-01-20T01:49:12Z")
Thank you very much for your reply! I’m using openfoam-v2206 and the official openfoam-adapter. My fluid solver is compressibleInterFoam (but with the modification of removing T),which may be different from interFoam in terms of the reason for the error in calculating the force. I’m still confused about the deformation of the interface mesh.I need further checks. Any suggestions will be appreciated! 😊 ---
**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 20, 2023, 6:55am UTC](https://precice.discourse.group/t/caculix-diverged-when-solving-multiphase-fsi-problem-with-compressibleinterdymfoam/1271/8 "2023-01-20T06:55:12Z")
Have a look at the links I posted above, I understand that other users have faced similar issues.