Does anyone know how can I model two fluids in FLOW-3D. Am I need two mesh blocks for them. Unfortunately I did not find anything in User Manual unusefull.

Regards, Armen

No, you don't have to have two mesh blocks for them. In two fluids model, fluid #1 has the fluid fraction of 1, and fluid #2 has 0. The fluid fraction between 0 and 1 means the mixture of two fluids. When you create initial fluid regions, just make sure the fluid fraction for each region is assigned with the correct value. The same applies to the boundary conditions.

In this case when I need to include surface tension I do not know which one surface tension is on - water or oil, for example.

Armen,

Surface tension is not a property of a fluid, rather of the interface between two media. So when you turn it on in oil-water case, it applies to the interface between oil and water.

Thanks a lot.