There is no built in module. Or a “formula” for “fluid” or anything remotely close to it.
You can try to use a PhysX branch (nvidia flow) maybe. But even then it’s a lot more going on than entering a formula.
Normally, all that water is, normally, is a glorified material shader where you take a flat mesh and distort it at runtime so that it appears to be water like.
Reactions and movement are done via render targets and flow maps.
Surface movement is done by panning normals / and or other things around.
The best approximation of fluid simulation is done with particles. And you can see it in Nvidia Flex.
You could try to make something similar via Niagara, maybe, but you’d need a much deeper set of skills than just “a physics formulae” to get to anything.
Try a better engine for theoretical physics if you don’t need this for a game or to release something that has to be made with UE4. There’s tons of better suited solutions for testing out theoretical formulae.