[Fabian Web]

Hello everybody,


I am trying to set up a case of a pipe. The inlet is a totalPressure boundary and the outlet a static pressure boundary. I am using the rhoSimpleFoam solver since I want to get a high pressure difference in the end. Until now the pressure difference is set to a low value because the simulation does not converge even with low pressure differences. The simulation stops (depending on the settings) after around 30 iterations.


Setting up the simulation with a mass flow inlet works perfectly fine.



As far as i can tell the error occurs at the inlet. Here the velocity close to the wall is very high compared to the rest of the domain.


Can you tell me what I have to look out for when setting up compressible simulations of internal flow with totalPressure inlets and static pressure outlets?


These are the boundaries:
p:

    inlet
    {
        type            totalPressure;
    rho        rho;
    psi        thermo:psi;
    gamma        1.3;
    value        uniform 5000000;
    p0        uniform 5000000;
    }

    outlet
    {
        type            uniformFixedValue;
        uniformValue    table
    (
         (0 4999000)
        (5000 4999000)
        (20000 4900000)
        (25000 4900000)
        (250000 100000)
    );
    }

    "(?i).*walls"
    {
        type            zeroGradient;
    }

U:

    inlet
    {
        type            pressureInletOutletVelocity;
    value        uniform (0 0 0);
    }

    outlet
    {
        type            pressureInletOutletVelocity;
    value        uniform (0 0 0);
    }

    "(?i).*walls"
    {
        type            noSlip;
    }

T:

    inlet
    {
        type            fixedValue;
        value           $internalField;
    }

    outlet
    {
        type            inletOutlet;
        value           $internalField;
        inletValue      $internalField;
    }

    "(?i).*walls"
    {
        type            zeroGradient;
    }

Initialization:


p:
internalField uniform 4999500


U:
internalField uniform (0.1 0 0)


T:
internalField uniform 293.15