[ivan_cozza]

Hi to everybody!
I need to control explicitly the interpolation scheme used in the fvc::grad operator. I read that if I use fvc::grad(phi), where phi is a vol<type>Field, the gradient is performed with the linear interpolation of phi on the cell-faces, while if I whant to control the interpolation scheme I have to set phi to a surface<type>Field.
The problem is that if I put

surfaceTensorField phi = mesh.Sf()*u1;

it doesn't work!
What's wrong?
Thank you, Ivan

[schmidt_d]

Ivan,
Actually, grad(phi) uses the corresponding technique stipulated in the fvSchemes file, which is not always linear interpolation. You can control this behavior by changing inputs, not code.
-DPS

[ivan_cozza]

David,
you mean that if I want to compute my gradient of volScalarField p with a (for example) cubic scheme I just have to write:

fvc::grad(p)

and after in the fvSchemes I have to write

gradSchemes
{
default Gauss cubic;
}

?
If it is, I misunderstood the programmer's guide passage in which it says that if put a vol<type>Field in a fvc::div or in a fvc:grad, the code uses by default a linear centred interpolation for the variables...