How to create the free surface interface in OpenFOAM for two phase flow.
 

Now I am simulating CFD for my project but I don't know how to create the free surface interface in OpenFoam. My simulation has shown below the picture it is a two-phase flow simulation. My project requested have to use the DNS turbulence model to resolve.

[IMG]https://ibb.co/5sfFJW7]

please give me any advice! thank you so much