[wei123]

Hi all,

I am trying to define several 3d-porous zones in my mesh. I based my case on the angled duct tutorial. My issue is that I added an e3 coordinate for my z-coordinate (the angled Duct tutorial has only e1 and e2), thinking that OpenFOAM will automatically detect that this should be a 3d case.

Here is my porosity Properties:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2012                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "constant";
    object      porosityProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

porosity1
{
    type            DarcyForchheimer;

    cellZone        insideZone1;

    d   (5e10 5e10 5e10);
    f   (0 0 0);

    coordinateSystem
    {
        origin  (0 0 0);
        e1      (1 0 0);
        e2      (0 1 0);
	e3	(0 0 1);
    }
}

porosity2
{
    type	    DarcyForchheimer;

    cellZone        insideZone2;

    d   (5e10 5e10 5e10);
    f	(0 0 0);

    coordinateSystem
    {
	origin	(0 0 0);
	e1	(1 0 0);
	e2	(0 1 0);
	e3	(0 0 1);
    }
}

porosity3
{
    type	    DarcyForchheimer;

    cellZone        insideZone3;

    d   (5e10 5e10 5e10);
    f	(0 0 0);

    coordinateSystem
    {
	origin	(0 0 0);
	e1	(1 0 0);
	e2	(0 1 0);
	e3	(0 0 1);
    }
}

// ************************************************************************* //

However, when running porousSimpleFoam, only e1 and e2 are detected:

/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2012                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : _7bdb509494-20201222 OPENFOAM=2012
Arch   : "LSB;label=32;scalar=64"
Exec   : porousSimpleFoam
Date   : Jan 29 2022
Time   : 11:56:44
Host   : MSI
PID    : 1462
I/O    : uncollated
Case   : /home/wei/OpenFOAM_files/work_ICVT/yarn1
nProcs : 1
trapFpe: Floating point exception trapping enabled (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster (fileModificationSkew 5, maxFileModificationPolls 20)
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 0


SIMPLE: no convergence criteria found. Calculations will run for 100 steps.

Reading field p

Reading field U

Reading/calculating face flux field phi

Selecting incompressible transport model Newtonian
Selecting turbulence model type RAS
Selecting RAS turbulence model kEpsilon
RAS
{
    RASModel        kEpsilon;
    turbulence      on;
    printCoeffs     on;
    Cmu             0.09;
    C1              1.44;
    C2              1.92;
    C3              0;
    sigmak          1;
    sigmaEps        1.3;
}

No MRF models present

No finite volume options present
Creating porosity model list from porosityProperties

Porosity region porosity1:
    selecting model: DarcyForchheimer
    creating porous zone: insideZone1
    origin: (0 0 0) e1: (1 0 0) e2: (0 1 0)
    local bounds: (14.16092 31.72034 10.04544)

Porosity region porosity2:
    selecting model: DarcyForchheimer
    creating porous zone: insideZone2
    origin: (0 0 0) e1: (1 0 0) e2: (0 1 0)
    local bounds: (14.14524 31.72034 10.05064)

Porosity region porosity3:
    selecting model: DarcyForchheimer
    creating porous zone: insideZone3
    origin: (0 0 0) e1: (1 0 0) e2: (0 1 0)
    local bounds: (28.40675 24.12406 9.895435)

Using pressure implicit porosity

Starting time loop

Time = 1

GAMG:  Solving for p, Initial residual = 1, Final residual = 0.02127579, No Iterations 6
time step continuity errors : sum local = 6.154702e-05, global = -1.226986e-05, cumulative = -1.226986e-05
smoothSolver:  Solving for epsilon, Initial residual = 0.9990214, Final residual = 7.133068e-09, No Iterations 2
smoothSolver:  Solving for k, Initial residual = 1, Final residual = 4.369756e-06, No Iterations 2
ExecutionTime = 5.16 s  ClockTime = 5 s
...

How could I make porousSimpleFoam detect e1, e2 and e3? Or how could I define my 3d-porous zone correctly?

Thanks a lot in advance!

[Yann]

Hi,

Your porous zone is already 3D.

The coordinate system is defined as an orthonormal basis, hence you only need to define the origin and 2 vector axis, as the 3rd one will be automatically created based on the 2 other vectors. This is why only the 2 first vectors are used by the solver when creating the porous zones.

You only have to define 2 of the 3 vectors, but you can define any of them (e.g. e1+e2, or e1+e3, etc...)

Cheers,
Yann