Channel flow: Inlet pressure AND uniform velocity?
 

A fluid flows between 2 plate in 2 dimensions. This is a channel flow. The flow is driven by a given pressure at the inlet and a given pressure at the outlet. The default boundary condition available in Comsol (and Fluent too I think)is:
"fixed pressure" with "no viscous stress".

I would like to impose a "UNIFORM VELOCITY" (du/dy = 0) instead of a "no viscous stress", along with the given inlet pressure, so that a boundary layer develop as a consequence of the given pressure difference between the inlet and the outlet.

To summarize, I would like to know how to impose this new boundary condition, in comsol or FLuent:

INLET: "fixed pressure" with "UNIFORM VELOCITY (du/dy = 0)".

Keep me posted.