problem during two-phase flow
 

hi everybody ,I tried to model a two-phase-flow by "pressure inlet" and "pressure outlet" in FLUENT, and I use the mixture model, when I checked the "slip velocity" ,FLUENT announced "floating point exception" and suddenly solve is terminate with error. And when I didn't check the "slip velocity" ,FLUENT would complete the calcultion successfully. But I want to know the distribution of gas phase, so I had to choose the "slip velocity", right? What can I do? I would be very grateful for any advice. And I'm very sorry for my poor English.