mhd module in fluent
 

I am trying to simulate a magnetorheological fluid flow in a cylindrical channel with conducting wall.
I am not sure what value of uds-0 and uds-1 should i enter at the inlet and outlet. will it be same as the exterior applied Bo.

The boundary condition on the induced magnetic intensity depends upon the path of the return current outside of the channel. See Electromagnetodynamics of Fluids by Hughes, W F and Young, F J. I prefer to use FlexPDE software in which I can specify my own partial differential equations and boundary conditions.