Hi everybody. I'm trying to s
 

Hi everybody.
I'm trying to solve a simple case to test the twoPhaseEulerFoam solver. The problem is that of the demixing of bubbles flowing through a channel dispersed in water. But I have some problem. After a couple of time steps, reversed flow occurs at the outlet boundary. I assume there is some problem with the BC. Is there anybody who had a similar problem? I set the boundary condition as follows:

Ua

boundaryField
{
inlet
{
type fixedValue;
value nonuniform List<vector>
18
(
(0 0 0)
(0.0319305 0 0)
(0.0635875 0 0)
(0.0943479 0 0)
(0.123419 0 0)
(0.1498 0 0)
(0.172243 0 0)
(0.189193 0 0)
(0.19873 0 0)
(0.19873 0 0)
(0.189193 0 0)
(0.172243 0 0)
(0.1498 0 0)
(0.123419 0 0)
(0.0943479 0 0)
(0.0635875 0 0)
(0.0319305 0 0)
(7.21645e-17 0 0)
)
;
}
outlet
{
type zeroGradient;
}
lowerWall
{
type slip;
}
upperwall
{
type slip;
}
defaultFaces
{
type empty;
}
}

Ub

boundaryField
{

inlet
{
type fixedValue;
value nonuniform List<vector>
18
(
(0 0 0)
(0.0319305 0 0)
(0.0635875 0 0)
(0.0943479 0 0)
(0.123419 0 0)
(0.1498 0 0)
(0.172243 0 0)
(0.189193 0 0)
(0.19873 0 0)
(0.19873 0 0)
(0.189193 0 0)
(0.172243 0 0)
(0.1498 0 0)
(0.123419 0 0)
(0.0943479 0 0)
(0.0635875 0 0)
(0.0319305 0 0)
(7.21645e-17 0 0)
)
;
}

outlet
{
type zeroGradient;
}

lowerWall
{
type fixedValue;
value uniform (0 0 0);
}

upperwall
{
type fixedValue;
value uniform (0 0 0);
}

defaultFaces
{
type empty;
}
}


alpha

boundaryField
{
inlet
{
type fixedValue;
value uniform 0.0257;
}

outlet
{
type zeroGradient;
}

lowerWall
{
type zeroGradient;
}

upperwall
{
type zeroGradient;
}

defaultFaces
{
type empty;
}
}

I also tried to change the BC to "calculated" but
unfortunately with no success. I get the following message:

--> FOAM FATAL IO ERROR : keyword value is undefined in dictionary "/nfs/home/lee/OpenFOAM/lee-1.4.1/run/tutorials/twoPhaseEulerFoam/channelFlow_in ternal/0/alpha::outlet"

file: /nfs/home/lee/OpenFOAM/lee-1.4.1/run/tutorials/twoPhaseEulerFoam/channelFlow_int ernal/0/alpha::outlet from line 42 to line 42.

From function dictionary::lookupEntry(const word& keyword) const
in file db/dictionary/dictionary.C at line 146.

FOAM exiting



Thanks for any hint.
Joao.