[zqlhzx]

Hi foamers,
I want to simulated a regular pipe with a interface in the middle of the geometry.The length(X-direction) is 200mm,heigh(Y-direction) is 50mm and wide(Z-direction) is 50mm.The interface is at the location of the length is 100mm.Both domains are fluid and one is named fluid1 and another is named fluid2.The number is (50 25 25 ).So the interface is named fluid1_to_fluid2 and fluid2_to_fluid1.
This is my geometry.
geometry.jpg
The solve I used is modified from chtmulRegionFoam with solid(OF2.0.1)!
The case can be run ,but the result is strange for me ,and it is wrong.
Time 0.005.jpg
The vilocity is clearly wrong at the middle cell(near the interface).I think I define the wrong U boundry of the interface.
Please see my blockMeshDict,U boundry of fluid1 and fluid2.
blockMeshDict:

FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

convertToMeters 1;

vertices
(
    (-0.1 -0.05  -0.05)
    ( 0.1 -0.05  -0.05)
    ( 0.1  0.05  -0.05)
    (-0.1  0.05  -0.05)
    (-0.1 -0.05   0.05)
    ( 0.1 -0.05   0.05)
    ( 0.1  0.05   0.05)
    (-0.1  0.05   0.05)
);

blocks
(
    hex (0 1 2 3 4 5 6 7) (50 25 25) simpleGrading (1 1 1)
);

edges
(
);

boundary
(
    topwall
    {
        type wall;
        faces
        (
            (3 7 6 2)
        );
    }
    inlet
    {
        type patch;
        faces
        (
            (0 4 7 3)
        );
    }
    outlet
    {
        type patch;
        faces
        (
            (2 6 5 1)
        );
    }
    bottomwall
    {
        type wall;
        faces
        (
            (1 5 4 0)
        );
    }
    minZ
    {
        type wall;
        faces
        (
            (0 3 2 1)
        );
    }
    maxZ
    {
        type wall;
        faces
        (
            (4 5 6 7)
        );
    }
);

mergePatchPairs
(
);

boundry of fluid1(domain 1)

6
(
    topwall
    {
        type            wall;
        nFaces          625;
        startFace       45000;
    }
    inlet
    {
        type            patch;
        nFaces          625;
        startFace       45625;
    }
    bottomwall
    {
        type            wall;
        nFaces          625;
        startFace       46250;
    }
    minZ
    {
        type            wall;
        nFaces          625;
        startFace       46875;
    }
    maxZ
    {
        type            wall;
        nFaces          625;
        startFace       47500;
    }
    fluid1_to_fluid2
    {
        type            directMappedWall;
        nFaces          625;
        startFace       48125;
        sampleMode      nearestPatchFace;
        sampleRegion    fluid2;
        samplePatch     fluid2_to_fluid1;
        offsetMode      uniform;
        offset          (0.002 0 0);
    }
)

boundry of fluid2(domain 2)

6
(
    topwall
    {
        type            wall;
        nFaces          625;
        startFace       45000;
    }
    outlet
    {
        type            patch;
        nFaces          625;
        startFace       45625;
    }
    bottomwall
    {
        type            wall;
        nFaces          625;
        startFace       46250;
    }
    minZ
    {
        type            wall;
        nFaces          625;
        startFace       46875;
    }
    maxZ
    {
        type            wall;
        nFaces          625;
        startFace       47500;
    }
    fluid2_to_fluid1
    {
        type            directMappedWall;
        nFaces          625;
        startFace       48125;
        sampleMode      nearestPatchFace;
        sampleRegion    fluid1;
        samplePatch     fluid1_to_fluid2;
        offsetMode      uniform;
        offset          (-0.002 0 0);
    }
)

U boundry for fluid1

FoamFile
{
    version     2.0;
    format      ascii;
    class       volVectorField;
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 1 -1 0 0 0 0];

internalField   uniform (0 0 0);

boundaryField
{
    inlet
    {
        type            turbulentInlet;
        referenceField  uniform (10 0 0);
        fluctuationScale (0.2 0.1 0.1);
        value           uniform (10 0 0);
    }

    fluid1_to_fluid2  
    {
         type            zeroGradient;
    }

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

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

    minZ
    {
         type            fixedValue;
        value           uniform (0 0 0);
    }
    maxZ
   {
         type            fixedValue;
        value           uniform (0 0 0);
    }
}

U boundry for fluid2

dimensions      [0 1 -1 0 0 0 0];

internalField   uniform (0 0 0);

boundaryField
{
      outlet
        {
              type            inletOutlet;
              inletValue      uniform (0 0 0);
              value           uniform (0 0 0);
        }
    
        fluid2_to_fluid1  
        {
                   type            directMapped;
               value           uniform (0 0 0);
               setAverage      true;
                   average         (10 0 0);
        }
    
        topwall
        {
            type            fixedValue;
            value           uniform (0 0 0);
        }
    
        bottomwall
        {
            type            fixedValue;
            value           uniform (0 0 0);
        }
    
        minZ
        {
             type            fixedValue;
             value           uniform (0 0 0);
        }
        maxZ
       {
             type            fixedValue;
             value           uniform (0 0 0);
       }
}

Did I set the right boundry for interface?How can I solve my problem?Please onesome can give me some advices!After running th case successly,I will solve turbulent flow in the fluid1 and solve combustion in the fluid1.Now it is my first step!