[dalasrevo]

Hello dear OpenFOAM community,

I have a problem that I could not solve even with a lot of searching in the forum (most probably I have already read many threads where a solution could be found, but I did not understand it):
I have a 3D structure meshed with cfMesh. It starts with a free surface, followed by a pressure section, which then goes back to an area with free surface. Now I want to measure a flow (mass flow) at two points, each of which is the transition from the free mirror to the pressure area, to find out at which side how much flows through. I would like to do the whole thing at runtime of interFoam and not in paraView.

Unfortunately I can't show the model, but I attach a sketch in 2D to clarify my problem: flow is from left to right (black open regions are free surface, blue is pressure section, red is a deflector wall which parts the flow and ends at the pressure section. Green and cyan are the two places where I would like to measure my massflow)


I have placed the two faces I would like to measure on as .stl under constant/triSurface.
How do I proceed now?
I have tried so far, among other things, to enter the following in the controlDict:

    flow_left
    {
    type surfaces;
    libs ("libsampling.so");
    writeControl writeTime;
    interpolationScheme cellPoint;
    surfaceFormat stl;
    setFormat raw;
    surfaces
    (
        flow_left
        {
        type sampledTriSurfaceMesh;
        surface flow_left.stl;
        source boundaryFaces;
        interpolate true;
        }
    );
    fields (U mag(U));
    }

flow_right
    {
    type surfaces;
    libs ( libsampling.so );
    writeControl writeTime;
    interpolationScheme cellPoint;
    surfaceFormat stl;
    setFormat raw;
    surfaces
    (
        flow_right
        {
        type sampledTriSurfaceMesh;
        surface flow_right.stl;
        source boundaryFaces;
        interpolate true;
        }
    );
    fields (U mag(U));
    }

Funnily enough, what happens now is that a copy of my flow_left.stl and flow_right.stl is placed in each folder in postProcessing. Funny, but definitely not what I want. I have obviously messed up everything that is possible to mess up.


I'm totally at a loss and would really appreciate some help. If there is a completely different approach to solve my problem, I am of course open to that as well.