SimScale CAE Forum

Solution diverged, but no mesh errors


#21

ok, thank you, i will test it.

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


    i think at this point the downwater has no influnce to the upperwater, because of the velocity and the gradient of the arch.

  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


#22

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

Here is a video, with the “goal” the waterlevel measurement.

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 ?

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 ?
https://www.simscale.com/workbench/?pid=3729340243366761061&rru=3d163478-49e5-4199-bce2-0967942bb7a9&ci=48c68461-0126-426e-9d21-69c6874783f3&ct=CONVERGENCE_PLOT&mt=SIMULATION_RESULT
Best regards
Kai