[mm66]

Dear Foamers,


I am working on a case where I have to use a smaller geometry by achieving fully developed condition at the inlet (due to its complexity simulating a bigger geometry takes way too long)...


To do so, I imposed the following boundary condition on U:

    outlet
    {
        type                 zeroGradient;
        value               uniform (0 0 0);
    }
    inlet
    {
        type                 mapped;
        interpolationScheme cell;
        value               uniform (0 0 -0.4021);
        setAverage   false;
    }

My intention is to achieve 1.65 kg/s of mass flow rate. My calculation shows it is equivalent to 0.4021 m/s. So I conducted the simulations and the mass flow rate is changing in the range 3 to 4 kg/s (!)


Here is my main question: So I made a change and imposed "setAverage" as follows:

    outlet
    {
        type                 zeroGradient;
        value               uniform (0 0 0);
    }
    inlet
    {
        type                  mapped;
        interpolationScheme cell;
        value                uniform (0 0 -0.4021);
        setAverage    true;
        average           (0 0 -0.4021);
    }

Now what I see in the console is that the mass flow rate goes from roughly 1.65 to roughly -1.65 kg/s successively. So for even iterations it is positive while for odd iterations it is negative. Any ideas guys? Please help.


Cheers,
MJ