Multiphase simulation
 

Hi, I am simulating a gas-liquid-solid multiphase flow in bubble column. I want to know that if I set the initial height of liquid if equal to the reactor height, then how to set the top boundary to make the system has mass balance? and if the unstructured mesh has huge influence on the convergence? Thank you very much!

In general any good quality mesh is fine. For some classes of problems (eg free surface with surface tension) the mesh quality requirement is much stricter and an unstructured mesh is not a good idea. A sensitivity check between an unstructured and structured mesh is a good idea here to see whether your simulation is sensitive to it.

Multiphase simulation
 

Thank you very much!