hi,I'm blocked by the convergence problem of three phase flow. what i model is that oil,air and water flow through a pipe.

inlet:Cartesian Velocity Components->0,0,3m/s outlet: open,Static Pressure for Entrainment->

->Relative Pressure = 1 [atm] domain: Reference Pressure = 1 [atm] BUOYANCY MODEL: Buoyancy ReferenceDensity=>oilreference air,water---dispersed oil---------continuous ihomogeneous model,no turbulence,

MOMENTUM TRANSFER: Ishii Zuber i take the most Recommended Configurations of Boundary Conditions ,and the simplest fluid model,but it didn't convergence.Where is the problem??

eager to your responses!thank you

The most common reason for convergence failure is a poor mesh. Since you are modeling a pipe it should not be hard to get a good hexahedral mesh. Be sure to include small mesh cells near the wall. Even without turbulence, it is important to capture flow patterns near the wall because there is a steep velocity gradient compared to the bulk fluid.

If you are solving an energy equation as well, it is much harder to obtain convergence.

yes,the hexa mesh is good.And what do you mean that"include small mesh cells near the wall"?How can i modify it? And i have simulated water-air two phase flow with turbulence and momentum trasfer convergent.then i do the three phase desire for a convergence result with a simple model. Is there any other problem about my case ，or some advice？ thank you

Does the three-phase flow converge so hard??help