[billy]

I would like to know if there is a way to define the boundary conditions as a function (x, y, z). For example, I wanted to define a radial velocity on a patch and I don't know how to do it.

[henry]

There are plenty of example codes to show you how to do this, setGamma from the interFoam tutorial for example or perhaps engineSwirl or engineSwirl2 are closer to what you want.

The issue of setting boundary values has also been discussed here with example code so try doing a search, you might find something useful.