# Solution diverged, but no mesh errors

**URL:** <https://www.simscale.com/forum/t/solution-diverged-but-no-mesh-errors/86422>\
**Category:** Project Support\
**Created:** [September 29, 2019, 6:44pm UTC](https://www.simscale.com/forum/t/solution-diverged-but-no-mesh-errors/86422 "2019-09-29T18:44:08Z")\
**Posts on this page:** 2\
**Page:** 2

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**Author:** ![Kai\_himself](https://www.simscale.com/forum/letter_avatar/kai_himself/32/6_22734026db12803ebb3e059622ac3534.png) [@Kai\_himself](https://www.simscale.com/forum/u/Kai_himself)\
**Post date:** [October 9, 2019, 5:57am UTC](https://www.simscale.com/forum/t/solution-diverged-but-no-mesh-errors/86422/21 "2019-10-09T05:57:30Z")

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ok, thank you, i will test it.

1. Did you thing, to cut the model at this point, will decarease the caluclation duration ?  

2. May get ap1 (Water) in the arch, as subdomain with a cylinder ?

I have to search a way to reduce the time, without increase the used cores. :).

best regards  
Kai

---

<div class="post-metadata">

**Author:** ![Kai\_himself](https://www.simscale.com/forum/letter_avatar/kai_himself/32/6_22734026db12803ebb3e059622ac3534.png) [@Kai\_himself](https://www.simscale.com/forum/u/Kai_himself)\
**Post date:** [October 12, 2019, 12:35pm UTC](https://www.simscale.com/forum/t/solution-diverged-but-no-mesh-errors/86422/22 "2019-10-12T12:35:58Z")

</div>

So, i make a few new simulations, with the cropped geometry.

Here is a video, with the “goal” the waterlevel measurement.  
https://www.youtube.com/embed/iBIUUB66vFw?feature=oembed&wmode=opaque

The bc at the outlet (all values zero gradient) looks like it’s working well.  
I the waterlevel is not longer rising at 8 seconds, so i think we have a stady state ? May i have to calculate 15 seconds ?  
The time duration for 10 seconds are 639 min and 85 core hours.  
I made a chart, with the delta t of each time step and the runtime.  
The deltaT places itself at \< 2.5e-04 seconds, may is it possible to increase it ?  
Is the timestep only based on the courant value ?

 ![Time_Steps](https://www.simscale.com/forum/uploads/default/original/3X/c/d/cd2967ff9706ccec9af3f7df118e1b2b5608b54f.jpeg)

I got two more question.  
The Run 3 Mesh 3 5 sec and the Run 4 Mesh 3 10 sec are totaly equal, except the simulation time.  
At the Run 4 i got a notification because of high courant values \> 1. Why only at Run 4 not in Run 3 ?

At the convergence plot of Run 4, you can see that the residual of p\_rgh jumps up and down from 5 seconds runtime till the end. May its responsible for the little deltaT at the time steps ?

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Best regards  
Kai

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