how to extract the components of radial and tangential velocities
 

hi everyone,
I am studying the inner flow of pump impeller by OpenFOAM-dev-1.5 with MRFSimpleFoam solver, compared to the experimental data. After numerical calculation, i can extract the x,y,z components of the relative velocity with "foamCalc components Urel" and i need to visualize the radial and tangential velocities. Is there a function to extract the components of them from cartesian coordinate system?

Thanks in advance!
jennifer