CFD Online Discussion Forums - mappedPatch and weird profiles

Hi all,

After weeks (too many) of trying to solve this stuff I come here the forum to ask for advice. I am trying to simulate a simple case. It is a duct where no gravity applies with fully developed flow profile inside. The idea is to heat the duct and take a look to the temperature profile radially and its evolution axially.

I tried BC cyclic for inlet and outlet patches, and got a great U profile, but the problem was that I could not see any evolution of the temperature profile, because all the flow what heated at the same pace.

I then thought that what I needed was a "cyclic" BC for the U, and a "patch" BC (fixed value) for the T's.

Here is where it comes to me that I need the mappedPatch BC. I have read several threads where it is somehow explained how it works, but it is not doing so to me.
I have checked out too the pitzDailyMapped, but no success again.
I attach in this message a picture where the weird profile is shown, and the relevant files to this. It could be some tiny detail I am not considering.

Inlet is the upper side (called 'entrada'). I can see there that in the first layer of cells is is well mapped, but somehow it messes the profile.

I'd like ask is anybody has an idea on how can I arrange this problem. I think this is one of the easiest cases ever, but I haven't been able to manage answers like this, which I think is the same case: http://www.cfd-online.com/Forums/ope...-trasnfer.html

Thanks in advance.

Dan

Code:

FoamFile

{

    version     2.0;

    format      ascii;

    class       polyBoundaryMesh;

    location    "constant/polyMesh";

    object      boundary;

}

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //



3

(

    entrada

    {

        type            mappedPatch;

        nFaces          125;

        startFace       14475;

        sampleMode      nearestCell;

        sampleRegion    region0;

        samplePatch     none;

        offsetMode      uniform;

        offset          (0 0 -0.2);

    }

    sortida

    {

        type            patch;

        nFaces          125;

        startFace       14600;

    }

    paret

    {

        type            wall;

        nFaces          800;

        startFace       14725;

    }

)

Code:

FoamFile

{

    version     2.0;

    format      ascii;

    class       volVectorField;

    object      U;

}

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //



dimensions      [0 1 -1 0 0 0 0];



internalField   uniform (0 0 -0.00011244);



boundaryField

{

    entrada

    {

        type             mapped;

        value            uniform (0 0 -0.00011244); 

        interpolationScheme    cell;

    setAverage        true;

    average            (0 0 -0.00011244);



    }



    sortida

    {

        type            zeroGradient;

    }



    paret

    {

        type            fixedValue;

        value           uniform (0 0 0);

    }

Code:

FoamFile

{

    version     2.0;

    format      ascii;

    class       dictionary;

    location    "system";

    object      fvOptions;

}

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //



momentumSource

{

    type            pressureGradientExplicitSource;

    active          on;        //on/off switch

    selectionMode   all;       //cellSet // points //cellZone



    pressureGradientExplicitSourceCoeffs    // pressureGradientExplicitSource.H

                        // Ubar == average velocity

    {

        fieldNames  (U);

        Ubar        ( 0 0 -0.00011244 );

 

    }

}