Discovery Live follows no slip boundary condition by default. Hence, the particle velocity at any surface is equal to the velocity of surface itself. When you try to extract velocity at any stationary surface, it is expected to give zero value as result.
I tried the chart option to measure velocity on a surface in a sample model where, I applied Swirl on the surface. As expected, the velocity output I got was equal to the velocity of the surface.
I hope that explains the reason behind your observation. Please let me know if there is any further confusion.