CFD Online Discussion Forums - Selection of the outlet boundary condition

Hello OF-Users :D

I am trying to simulate a distribution of a incompressible fluid between different two spaces and I am not sure, how should I set up the boundary condition of the outlet.

The velocity for the inlet-flow is 1 m/s , and the with of inlet-face is 2 units.
the width of the outlet-faces is 42 units

I used this BC for the outlet:
for p :

Code:

    outlet

    {

        type            fixedValue;

        value          0;

    }

for U

Code:

   outlet

    {

        type            zeroGradient;

    }

but i did get any physical results and the solver "simpleFoam" dumped after 70 sec simulation-time.

So that is why I tried to use the conservation of the mass to define the flow velocity in the outlet (0,047619 m/s) ... and I defined the pressures BC as zeroGradient ..but ... It did not help either..

In the attachment is a screen-shot of the physical domain.
the fluid comes from left and go out from the right side.

Any suggestion?
Any help will be appreciated!