# IQN fails for quickly changing forces during wetting in a free-surface FSI problem

**URL:** <https://precice.discourse.group/t/iqn-fails-for-quickly-changing-forces-during-wetting-in-a-free-surface-fsi-problem/248>\
**Category:** Using preCICE\
**Tags:** inactive\
**Created:** [May 28, 2020, 4:36pm UTC](https://precice.discourse.group/t/iqn-fails-for-quickly-changing-forces-during-wetting-in-a-free-surface-fsi-problem/248 "2020-05-28T16:36:15Z")\
**Posts on this page:** 1\
**Showing post:** 9

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**Author:** ![Alphaoo1](https://yyz2.discourse-cdn.com/free1/user_avatar/precice.discourse.group/alphaoo1/32/497_2.png) [@Alphaoo1](https://precice.discourse.group/u/Alphaoo1)\
**Post date:** [September 17, 2020, 6:40am UTC](https://precice.discourse.group/t/iqn-fails-for-quickly-changing-forces-during-wetting-in-a-free-surface-fsi-problem/248/9 "2020-09-17T06:40:59Z")

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@KyleDavisSA I tried the setting, I think including `Forces0` in the acceleration surely helped.  
Before including the forces in the acceleration, the forces applied on the flap were in the magnitudes of \*e+03.  
Now they have come down to the magnitudes of \*e+02. I think I have to modify my OpenFOAM adapter further since this seems to be a case similar to the post by [Ulrich](https://precice.discourse.group/t/fsi-with-interfoam-and-calculix/277/5).

I have made the modifications implemented, but not sure.  
I will have a look at my adapter again.

For `<time-window-size value="1.e-3" />`, it run until almost `t=0.03`, which was similar to what I got before.  
For `<time-window-size value="1.e-4" />`, it run until `t=0.538698`, which is better than the explicit coupling with similar `<time-window-size`.

Unfortunately, the actual results are the same as before.

> [@Alphaoo1](#):
>
> ![mesh_overlap](https://global.discourse-cdn.com/free1/uploads/precice/original/1X/b08ef0903c90bd52f300c310b496c23ea08a2571.jpeg)
> 
> mesh\_overlap1509×804 257 KB

I am trying a case where the solid is a kind of a ramp, might have better results.

 ![interFoam_ramp_case](https://global.discourse-cdn.com/free1/uploads/precice/original/1X/2ccd41aff035683832f6d496c56d2ff1a07aeca8.png)

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