[ArathoN]

I want to simulate the fully developed flow in a rectangular channel and i decided to use the mappedpatch option with the solver simpleFoam.

I mapped the inlet with the outlet and I put as value variable the velocity i want like this:

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

internalField   uniform (0 0 0);

boundaryField
{
    inlet
    {
        type                  mapped;
        value                 uniform (9.07 0 0);
        interpolationScheme   cell;
        setAverage            false;
        average               (9.07 0 0);  
    }

    outlet
    {
        type            zeroGradient;
    }

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

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

    frontAndBack
    {
        type            empty;
    }
}

What i want is that the maximum velocity would be the given one, so it must be the center-line velocity. But after the simulation the velocity would increase and i can't figure out how i can make it stop doing it.

My hypothesis is that with mappedpatch it will try to maintain constant the massflow so the velocity at centerline represent the maximum flow and having the boundary layer the velocity will have to increase at the center-line cause near wall it's null. How can i counter this? I have the experimental data in 12 point of the channel height, can they be useful?

Here the interested part of blockmeshDict:

inlet
    {
        type mappedPatch;
        offset          ( 0.4 0 0 );
        sampleRegion    region0;
        sampleMode      nearestCell;
        samplePatch     none;
        faces
        (
            (0 5 11 6)
            (5 4 10 11)
        );
    }
    outlet
    {
        type patch;
        faces
        (

            (1 2 8 7)
            (2 3 9 8)          
        );