[csomerlot]

Which boundaries should I use to model velocity distribution in a pipe?

I believe I need 'fixedValue' for pand U in the inlet, and 'calculated' at the outlet, but thats not working. Is there any further documentation for the 'calculated' boundary?

[Moderator note: was originally located in the blockMesh forum]

[hjasak]

Not a particularly good location for this thread, but never mind :-)

The "calculated" boundary condition is just a place-holder for the situations where the code does not know what to do - for example when you are calculating a gradient of the field and you're not sure what the boundary conditions for that field should be. Also, you cannot specify both p and U at the same location for incompressible flows.

In your case, the appropriate set of b.c.-s are fixedValue U and zeroGradient p at the inlet and zeroGradient U and fixedValue p at the outlet.

Have a look at the tutorials, for example tutorials/simpleFoam/pitzDaily

Enjoy,

Hrv