A new boundary f(x,y) (x,y is coordinate of mesh)
 

Hello foamers,
I want to set a new boundary, which moves based on a function f(x,y) - x,y is the coordinate of this point in mesh. I saw the boundary oscillatingDisplacement, but I'm not sure if this boundary can give different displacement on different points. So here's my two questions:

1. In a boundary, how to read the coordinate (x,y) of mesh? Which function should be used?
2. Which boundary can set different displacement on different points?

Thank you!