[khoder Alshaar]

Hello,
of what I understand about zeroGradient boundary for a volumeVectorField, that it applies a zero-gradient condition from the patch internal field onto the patch faces. In other words, it copies the values from the volume of the cell to its boundary face. is this correct?

Then what does this condition do to pointVectorField such as the following?

FoamFile
{
    version     2.0;
    format      ascii;
    class       pointVectorField;
    location    "0";
    object      lmN;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [1 -2 -1 0 0 0 0];

internalField   uniform (0 0 0);

boundaryField
{
    top
    {
        type    zeroGradient;
    }
    .
    .
    .
    .
}

code is taken from explicitSolidDynamics solver