Consider the steady-state 2D-flow of an incompressible Newtonian fluid in a long horizontal rectangular channel. The bottom surface is stationary, whereas the top surface is moved horizontally at the constant velocity, . Determine the velocity field in the channel. Assume fully developed flow.
(Fig. 16c)
Assumption: is applicable
Fully developed flow:
(Note: this statement is equivalent to saying, neglect the end effects) Apply continuity:
For fully developed flow, first term is zero. is constant along y direction.
But, at y = ± (no- slip condition)
So, everywhere.
. Determine the velocity field in the channel. Assume fully developed flow.
is applicable 
is constant along y direction. 
at y = ± 
(no- slip condition)
everywhere. 
