SimScale CAE Forum

Simulation not converging/blowing up



I think my mesh is working properly, but when running the simulation, everything is blowing up after ~10 iterations. I’m not sure what to do at this point since the mesh seems to be ok. Am I missing something in the set up, perhaps in the Numerics that’s screwing it up?

Thanks again for the help.


Hi @ymlopes

I will look at the simulation setup and see what’s bothering the convergence. In the mean time I suggest you to try one simulation with K-epsilon turbulence model which usually provides a good convergence rate.



Hi @ymlopes

The problem is with the value of gauge pressure. You have set it to 100KPa . I think you got confused between the gauge pressure and absolute pressure. You have to assign a gauge pressure of 0 Pa on the outlet face.




Hmm, so I changed that and re-ran it, but it’s still blowing up, both with k-omega SST and k-epsilon. Any other thoughts?


Yes, change the pressure from 100KPa to 0 Pa everywhere(initial conditions, numerics etc…)
Also, global velocity of 102 makes no sense if you are giving an inlet velocity on one face. So even at 0th timestep, the velocity at each node(in the entire domain) is going to be 102m/s which is blowing this simulation


Finally!! the simulation has started :partying_face:. You had changed so many parameters :exploding_head:

Also, try to simulate this problem with K-epsilon turbulence model after making the above mentioned changes.



Yeah I think the global velocity initial condition was the problem. Thank you for your help, I really appreciate it!