Hello everyone. I have here a basic question, but have trouble finding the concrete solution. How do you simulate two different fluids in fluent? For example, I would like to set up a problem in which oil and water interact. What steps must I take to create a 2 fluid simulation? Thanks in advance for the help.

select a proper multiphase, you can use VOF if there is no thorough mixing happening else go for higher models

In the materials create the materials, in the phases panel define the phases with the above materials.

then ..give boundary and initial conditions. Follow the best practise if available.

-sujith

Thank you very much for your response. In my particular simulation, I have 3 types of fluid interacting in a microchannel: Water, dyed water, and immiscible oil. So, mixing will occur between water and dyed water, but not with the oil because it is immiscible. Which model do you recommend I use? Not too mention, in a microchannel, the Reynolds number is extremely low, practically zero, so any mixing is by diffusion or some minor circulation. What approach should I take? Thank you for your assistance.

I think you can make water & dyed water mixture as 1 phase and oil as another phase. In a micro channel the effect of surface tension may not be negligible. So you may use VOF multiphase and solve surface tension also. For using mixture and species diffusion u should enable species transport in the models.

Sujith