question on setFields
 

I am trying to model a cylindrical tank being filled with liquid, initially with 10% ullage and am having a hard time figuring out how to use setFields. How would I add my liquid field to the tank using setFields? I am bringing my mesh from cubit by exporting to fluent mesh then using fleuntMeshToFoam.

I think setFields is ideal for box shaped geometries.
I'm not sure this is what you want if you are using a cylinderical mesh.

So I suggest you have a look at funkySetFields.
With this tool you have by far more control over what you want to set.