[y_jiang]

Hi,

I am working on ScalarTransportFoam trying to add a distribution of source term.
For example, considering 1D convection-diffusion problem, if the source term is define as follow:

S(x)=ax+b (x1<x<x2)
S(x)=cx+d (x2<x<x3)
a, b, c, d are all constants

How to add this distribution in ScalarTransportFoam? Anyone made something similar?

Thank you and best regards

[Lieven]

Hi Jiang,

You can try something like:

volScalarField S
(
    IOobject
    (
        "S",
        runTime_.timeName(),
        mesh_,
        IOobject::NO_READ,
        IOobject::NO_WRITE
    ),
    mesh_,
    dimensionedScalar("S", pow(dimTime,-1)*T.dimensions(), 0.0)
)

forAll(mesh.C(),cellI)
{
    const point& Ccell = mesh.C()[cellI];
    if(Ccell.x() > x1 && Ccell.x() <= x2)
    {
        S[cellI] = a*Ccell.x() + b;
    }
    else if(Ccell.x() > x2 && Ccell.x() < x3)
    {
        S[cellI] = c*Ccell.x() + d;
    }
}

And next add

==
S

to the scalar transport equation. I wrote this from the top of my head so I didn't check if it compiles (actually, it won't since you need to define a,b,c and d among a few other things). But at least it might help you in the right direction.

Cheers,

L

[y_jiang]

Hi Lieven,

Thank you very much for your idea. It works for me. Sorry for the late reply cause I have been doing a different project for the last several months. Now I got a new problem about mesh manipulation. It is a kind of same as the previous one which I asked you. The thing is:
I am trying generate bedforms for my case, basically, the Mesh is just a 3D box and I want to modify the bottom from flat bottom to a sine wave surface. I have already written a utility for the bedform generation. I attached the .C file for you. But I want to make it more general, for example, if I just want generate the sine wave for the part which a<x<b. I have tried, but unfortunately didn't make it. Do you have any idea on this?

Thank you.

Yijiu

Originally Posted by Lieven

Hi Jiang,

You can try something like:

volScalarField S
(
    IOobject
    (
        "S",
        runTime_.timeName(),
        mesh_,
        IOobject::NO_READ,
        IOobject::NO_WRITE
    ),
    mesh_,
    dimensionedScalar("S", pow(dimTime,-1)*T.dimensions(), 0.0)
)

forAll(mesh.C(),cellI)
{
    const point& Ccell = mesh.C()[cellI];
    if(Ccell.x() > x1 && Ccell.x() <= x2)
    {
        S[cellI] = a*Ccell.x() + b;
    }
    else if(Ccell.x() > x2 && Ccell.x() < x3)
    {
        S[cellI] = c*Ccell.x() + d;
    }
}

And next add

==
S

to the scalar transport equation. I wrote this from the top of my head so I didn't check if it compiles (actually, it won't since you need to define a,b,c and d among a few other things). But at least it might help you in the right direction.

Cheers,

L

[y_jiang]

Hi Lieven,

I have already solved this problem. It is pretty simple. I just thought it in a wrong way at the very beginning.

Cheers,
Yijiu

[Mehar]

Originally Posted by y_jiang

Hi Lieven,

I have already solved this problem. It is pretty simple. I just thought it in a wrong way at the very beginning.

Cheers,
Yijiu

Hi, y_jiang...
Its an old thread, but I hope I can get a reply from you for how you actually solved your problem, and
I am also working on scalarTransportFoam, and I want to include a sink to it, any suggestion on how I can implement this.

Thanks
mehar