[ufocfd]

I am trying to specify a zeroGradient (velocity) within the codedFixedValue BC. I have done it something like this (snippet below) but it doesnt seem to work - at least Im not getting a zero gradient at the downstream boundary - any ideas (please) - have I made a mistake or missed something? Thanks.

// get velocity field
const volVectorField& U = db().lookupObject<volVectorField>("U");

forAll(Cf,facei) // face loop
{
// get index of cell adjacent to patch face
label celli = patch().faceCells()[facei];

//--------zeroGradient downstream
field[facei] = U[celli]; // Uface = Ucell

}