I have setup a complex transient 3D model with 13 layers in Feflow 5.2 with a 1st kind and a 3rd bc, several wells, transient recharge with default solver settings. Sometimes the simulations runs with some minor convergence errors but finishes. In most cases it suddenly slows down without any error message, so that each iteration takes a quite long time (minutes instead of a few seconds). The hydraulic heads then "rise to the sky" (no numerical values shown in legend!).
Everything in the model setup seems to be ok. Even with a more simple setup (5 layers) the same problems occur. I tried a lot of things described in the forum to make it run better (discretization, slope of the slices, etc.). After many tries I tried the model with Feflow 5.3 (same solver settings) and it worked without any problems.
Is there a bug in 5.2 that leads to such a strange behaviour? Is there any change in the solver setup/technique to 5.3? I could not see anything in the change notes. Since I am bound to Feflow 5.2 I would be happy if anyone could help me.
Thanks in advance!
