[Natalie2210]

Hi everybody,

I want to simulate pressure driven flow through a pipe. Up to now I have used the solver interFoam successfully, now, however, I want to test the effect of compressibility. Thus, I'd like to switch to the solver compressibleInterFoam.

I have found the tutorial depthCharge in the tutorials section and found out how to set psi and rho0, at least in the transportProperties-file. However, when I try to run the case I run into troubles. I somehow suspect the boundary conditions. I'm using the boundary conditions working well with interFoam (creating a pressure drop which makes the fluid move through the pipe):

alpha1

*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.1.1                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    object      alpha;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions      [0 0 0 0 0 0 0];
internalField   uniform 0;
boundaryField
{
    wall
    {
        type            zeroGradient;
    }
    wall2
    {
        type            zeroGradient;
    }
    outflow 
    {
        type            inletOutlet;
        inletValue      uniform 0;
        value           uniform 0;
    }
   inflow
   {
      type    fixedValue;
      value   1;  
   }
}
// ************************************************************************* //

p_rgh:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.1.1                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    object      p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions      [1 -1 -2 0 0 0 0];
internalField   uniform 0;
boundaryField
{
    wall
    {
        type           zeroGradient;
    }
    wall2
    {
        type           zeroGradient;
    }
    inflow
    {
        type            fixedValue;
        value           3.5e4;
    }
    outflow 
    {
        type            fixedValue;
        value           $internalField;
    }
}
// ************************************************************************* //

and U:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.1.1                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volVectorField;
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions      [0 1 -1 0 0 0 0];
internalField   uniform (0 0 0);
boundaryField
{
    wall
    {
        type            slip;
    }
    wall2
    {
        type            slip;
    }
    inflow 
    {
        type            pressureInletUniformVelocity;
        phi             phi; 
        rho             rho; 
        value           uniform (0 0 0);
    }
    outflow 
    {
        type            pressureInletOutletVelocity;
        phi             phi; 
        value           uniform (0 0 0);
    }
}
// ************************************************************************* //

Do I need to specify something else? Psi for example?

Thanks a lot,
Natalie

[Natalie2210]

Ok, I think I got it - I just used a time increment way to big in order to get a stable solution.

[pmdelgado2]

Could you share all of your case files?