Hi Ankit,

(IMHO as always when talking about NS) the pressure in incompressible NS
equations is just a Lagrange multiplier for enforcing the incompressibility
constraint and it is determined up to a constant. So Dirichlet bcs are not the
way to go. To impose pressure as "volumetric stress traction" you will need
Neumann-type bcs (dw_surface_ltr), but be careful in deriving the weak form of
the NS equations - do not forget some terms from integration by parts.

r.

On 07/24/2013 10:46 AM, Ankit Mahato wrote:
> Hi Guys,
>
> I had formulated the problem combining Navier Stokes with Energy Equation.
> For that I wanted to try out Couette flow with pressure gradient (*plane
> Poiseuille flow*) with Thermal boundary conditions. For simple Couette Flow
> ( pressure gradient =0 ) the code is working fine and giving us the proper
> velocity profile but how to do it with user defined pressure gradient.
> See Link - http://www2.mech.kth.se/~luca/Smak/rec5.pdf
> which will give us velocity profile for this flow.
> I tried imposing pressure boundary condition but it is not working out.
> I have attached the problem file.
>
> Regards,
> Ankit
>