[user9]

I am simulating 2-D axisymmetric miniature channel. I WANT TO STUDY AIR - WATER SLUG FLOW WITHOUT PHASE CHANGE.

IDEALLY FOR SLUG FLOW WE SHOULD USE VOF MODEL.

But I want to use EULERIAN - EULERIAN model where it asks for DIAMETER OF SECONDARY PHASE which is air in my case.

By default it takes 10^(-5) m .
What should be diameter of secondary phase?IMG_20200501_180151.jpg

[vinerm]

If the flow morphology is slug or segregated, you won't get good results with Euler until and unless the mesh is very fine. As far as length scale is concerned, you can use a size comparable to expected slug. A smaller size will cause over-interaction between phases and diffuse more momentum than otherwise expected.