CFD Online Discussion Forums - Odd behavior on the outlet

Hello Everyone.
I don't know if this is the correct place for my thread.
I'm trying to simulate the flow in an air supply system (using incompressible S-A DDES) as you can see in the attached photo and I'm interested only in the flow in the duct's end region, but I'm noticing an odd behavior, the semi-spherical surface should be an outlet but the flow is not completely exiting throw the outlet, and I think that could effect the solution quality.
My BC at the outlet:
For U:

Code:

    outlet

    {

        type            inletOutlet;

        value           $internalField;

        inletValue      $internalField;

    }

and for p:

Code:

    outlet

    {

        type            outletInlet;

        outletValue        uniform 0;

        value                uniform 0;

    }

Any one can explane the reason of this behavior
If this is wrong ... what I should use?
Or I should use different outlet shape for my simulation?
Thanks in advance.