The axisymmetric form of the Navier-Stokes equations
 

hello. I am an undergrad student and i needed help regarding how to deal with a cylinder with a rotating endwall problem set which comprises of my final year project. It has The axisymmetric form of the Navier-Stokes equations, in cylindrical coordinates and is formulated using the stream function vorticity method.

i have formed difference equations using second order difference schemes but i have no idea how to deal with the "r" terms that appear in them (r being the non-dimensional form of the cylinder radius).

Any guidance will be just awesome.
thanks