[r2d2]

Hello,
I have a question (or more) about rhoExplicit(Implicit)porousFoam:
1. In specifying e1 and e2 in the porousZones, that gives me the orientation of the resistance "vector", right?
2. How does a given value of K (permeability m**2) and porosity phi translate into the "d" and "f" terms of Darcy-Forchheimer or the C0/C1 parameters of powerLaw ? Does anyone have some references?
Cheers,
Radu

[olesen]

From the porousZone.H:

Porous zone definition based on cell zones and parameters obtained
from a control dictionary constructed from the given stream.
The orientation of the porous region is defined with the same
notation as a coordinateSystem, but only a Cartesian coordinate
system is valid.

Implemented porosity models:

powerLaw (C0/C1 parameters)
S = - rho * C0 * |U|^((C1 - 1) / 2) * U

Darcy-Forchheimer (d/f parameters)
S = - (mu * U * d + rho/2 * |U| * f) * U

The model does not include correction of the temporal terms.


This seems to cover all of your questions about orientation, porosity (no temporal terms yets) and the Darcy resistances.

[r2d2]

Yes, I saw porousZones...so d is the inverse of K and f dunno...(?) Does the porosity (phi) of a material enters the fray in anyway? (or just via K,
and possibly f)

[otsuki]

Hi,
The porosity is not considered explicitly
for both powerLaw and Darcy-Forchheimer models.
i.e. velocity U in these models is
not a "physical velocity" but a "superficial
velocity".
Masato

[markusrehm]

Hello,

I want to use different cell zones but only the first one is recognized. My porousZones-Dict looks as follows:

1
(
    cat1
    {
        porosity    0.5;
        Darcy
        {
            d   d [0 -2 0 0 0 0 0] (11111 11111 11111);
            f   f [0 -1 0 0 0 0 0] (111 111 111);
        }
    }
)

2
(
    cat2
    {
        porosity    0.6;
        Darcy
        {
            d   d [0 -2 0 0 0 0 0] (22222 22222 22222);
            f   f [0 -1 0 0 0 0 0] (222 222 222);
        }
    }
)

3
(
    cat3
    {
        porosity    0.7;
        Darcy
        {
            d   d [0 -2 0 0 0 0 0] (33333 33333 33333);
            f   f [0 -1 0 0 0 0 0] (333 333 333);
        }
    }
)

Should it be defined that way? The cell zones are available.

Regards, Markus.

[navier-stokes]

Hi Markus!
There may be a problem with your list definitions. Have a look at the UserGuide (Section 4.2.4).

[markusrehm]

Hello,

you are right it should read:

3
(
cat1
{
porosity 0.5;
Darcy
{
d d [0 -2 0 0 0 0 0] (11111 11111 11111);
f f [0 -1 0 0 0 0 0] (111 111 111);
}
}

cat2
{
porosity 0.6;
Darcy
{
d d [0 -2 0 0 0 0 0] (22222 22222 22222);
f f [0 -1 0 0 0 0 0] (222 222 222);
}
}

cat3
{
porosity 0.7;
Darcy
{
d d [0 -2 0 0 0 0 0] (33333 33333 33333);
f f [0 -1 0 0 0 0 0] (333 333 333);
}
}
)

Thank you, Markus.

[olesen]

It might be more convenient, and only very marginally less efficient, if you simply drop the size from the PtrList.
For example

(
    cat1
    {
    ...
    }

    cat2
        {
    ...
    }

    cat3
    {
    ...
    }
)

Internally it will simply use a linked-list during the reading and then move everything over to the PtrList.