I modified the region definitions to make sure that the wall nodes are not included. That did not solve the problem. I then changed the weak form of the Navier Stokes equations from: dw_div_grad.i2.Omega( fluid.viscosity, v, u ) + dw_convect.i2.Omega( v, u ) - dw_stokes.i1.Omega( fluid.one_b_rho, v, p ) = 0 to: dw_div_grad.i2.Omega( fluid.viscosity, v, u ) + dw_convect.i2.Omega( v, u ) + dw_v_dot_grad_s.i1.Omega(fluid.one_b_rho, v, p) = 0

This change works. I can now specify a boundary pressure and the pressure profile remains linear but is shifted to account for specified boundary pressure. With the old weak for, this behavior was not seen.

What could be the reason for this? Is it necessary to remove the pressure gradient term in the weak form?

Best, Nikhil