Solution diverges on the first time step with an extremely large time step.

[sidkamat]

Hi. I am running a multispecies problem but the solution ends within 3 seconds and the first time step in history.txt is extremely large. This is happening only for the multispecies problems. I tried refining my mesh and reducing my CFL number but the result is the same. I have attached my UCNS3D.DAT, MULTISPECIES.DAT, and history.txt files. Please let me know if I am setting up the problem incorrectly. history.txt MULTISPECIES.txt UCNS3D.txt

[TakisCFD]

pressure specified in UCSN3D.dat is zero (will not work with this value)-you must specify here the static pressure

[sidkamat]

Hi. I tried doing what you said and it is having the same issue. I even tried using a pressure inlet boundary condition but it is having the same effect. Can you tell me what I am doing wrong?

[TakisCFD]

the pressure specified at the UCNS3D.DAT is the static pressure. Check the examples provided in the test directory, look for the MULTISPECIES.DAT, the profile.f90 with the corresponding initial condition profile and the inflow_2d function to better understand what you need to specify

[sidkamat]

I have a simple liquid injection in a quiescent environment problem. Is it advisable to write a custom initial conditions profile or can the default initial condition profile handle this?

[TakisCFD]

you should create a custom initial conditions profile