[Artur]

Hi All,

I am trying to extract face centres and normal vectors of a set of faces described by a patch. It works fine for a stationary mesh but when I move the code to a dynamic mesh solver and apply rotation to the faces I am interested in the face normal vector does not update but the face centre does.

In other words, the second quantity of the following is always the same:

Info << mesh.Cf().boundaryField()[patchi][patchFaceI] << " "
     << mesh.Sf().boundaryField()[patchi][patchFaceI] << endl;

Any suggestions how to fix it? I'm digging through the code but haven't found anything yet...

All the best,

A

[Artur]

I'm sorry, I was looking at a wrong face. Everything works as it should, it was just me being stupid.

In case someone wonders, here's a piece of code computing the normal of a face (taken from primitiveMeshGeometry.C) I used to find the mistake:

    const labelList& f = mesh.faces()[faceI];
    const List<point>& p = mesh.points();
    
    label nPoints = f.size();
    
    vector sumN = vector::zero;

    point fCentre = p[f[0]];
    for (label pi = 1; pi < nPoints; pi++)
    {
        fCentre += p[f[pi]];
    }

    fCentre /= nPoints;

    for (label pi = 0; pi < nPoints; pi++)
    {
        const point& nextPoint = p[f[(pi + 1) % nPoints]];

        vector n = (nextPoint - p[f[pi]])^(fCentre - p[f[pi]]);

        sumN += n;
    }

    Info << 0.5*sumN << endl; // final result for the area vector