[fabrice]

Hi Foamers,
I am trying to define a constant source term with the solver pimpleFoam and I use channel395 case to test.
I modified the solver of pimpleFoam and add concentration equation to it:
fvScalarMatrix CEqn
(
fvm::ddt(C)+fvm::div(phi,C)+ fvm::laplacian(turbulence->nu()/Sc,C)
);
CEqn.solve();
then I want to define a constant source for concentration equation in certain area. How can I do this?
1,I try to use setFields but it only works on initial field
2,I found it can set in fvOption files
momentumSource
{
type meanVelocityForce;
active yes;

meanVelocityForceCoeffs
{
selectionMode all;

fields (U);
Ubar (0.1335 0 0);
relaxation 1.0;
}
}

In my case, I think openFoam dose not have concentration equation, what should I do, can you please give me some suggestions?

[Alasir]

The meanVelocityForce in fvOptions seem to be quite videly used for these kinds of things. It will be applied for all timesteps.

Do you get any errors by simply trying to run it?

[student666]

Hi,

I successfully applied this source term for velocity field, maybe you can use as well.

velocitySource
{
    type            vectorFixedValueConstraint;
    active          true;


    vectorFixedValueConstraintCoeffs
    {

        selectionMode   cellZone;
        cellZone         heater;
        volumeMode absolute;
        fieldValues
        {
            U           (0 1 0);
        }
    }
}

you can have a quite complete overview of fvOptions at
http://www.geocities.jp/penguinitis2...fvOptions.html

(just use google translate)

Regards

[RobertHB]

Great link! Thank you sooo much!

[fabrice]

Originally Posted by Alasir

The meanVelocityForce in fvOptions seem to be quite videly used for these kinds of things. It will be applied for all timesteps.

Do you get any errors by simply trying to run it?

Hi Alasir,
Sorry for my bad explanation, I mean people can use this method to define a source in momentum equation but in my case how can I add a constant source to concentration equation.

[fabrice]

Originally Posted by student666

Hi,

I successfully applied this source term for velocity field, maybe you can use as well.

velocitySource
{
    type            vectorFixedValueConstraint;
    active          true;


    vectorFixedValueConstraintCoeffs
    {

        selectionMode   cellZone;
        cellZone         heater;
        volumeMode absolute;
        fieldValues
        {
            U           (0 1 0);
        }
    }
}

you can have a quite complete overview of fvOptions at
http://www.geocities.jp/penguinitis2...fvOptions.html

(just use google translate)

Regards

Thanks a lot for your link I will read it. By the way, in my case I add concentration equation myself as far as I know openfoam only have utility for
momentum or energy source. Should I define it myself in solver every time step?

[student666]

Hi,

sorry, I thought you needed a velocity field source term.
Are you meaning you have to add a constant scalar source for a species?

If that's the case,
https://www.researchgate.net/publica...ers%27_version

has some more tutorials.

If you give more informations about your needs and what you're doing, others on this forum could be of much more help.

Regards

[fabrice]

Originally Posted by student666

Hi,

sorry, I thought you needed a velocity field source term.
Are you meaning you have to add a constant scalar source for a species?

If that's the case,
https://www.researchgate.net/publica...ers%27_version

has some more tutorials.

If you give more informations about your needs and what you're doing, others on this forum could be of much more help.

Regards

M.C
Thank you for help. What I am doing now is add convection diffusion equation to the solver 'pimpleFoam'. I want to simulate a constant pollutant source dispersion, for instance, in a channel. I do not know what's the proper way to define the source in some certain of the area.

[fidu]

Hi,
I would like to implement some additional source code for my porous media. I have already applied the Darcy-Frochheimer source term with fvOptions and explicitpourouszone for the momentum therm. Now I would like to implement the turbulent kinetic energy (TKE) and the turbulent dissipation rate (TDR) source term of my porous material. Both terms are dependent on the magnitude of the flow, epsilon, k and some constants. Could you recommend me a strategy how to implement this or are there source terms which I could easily modify?

My source terms are:





Sorry if this is stupid question but I quite new to all of this and would greatly appreciate all recommendation or hints

Best
fidu

[ali moeni]

Originally Posted by fidu

Hi,
I would like to implement some additional source code for my porous media. I have already applied the Darcy-Frochheimer source term with fvOptions and explicitpourouszone for the momentum therm. Now I would like to implement the turbulent kinetic energy (TKE) and the turbulent dissipation rate (TDR) source term of my porous material. Both terms are dependent on the magnitude of the flow, epsilon, k and some constants. Could you recommend me a strategy how to implement this or are there source terms which I could easily modify?

My source terms are:





Sorry if this is stupid question but I quite new to all of this and would greatly appreciate all recommendation or hints

Best
fidu

Hi there, did you find any solution?

[MMRC]

Hello,

For canopy sources/sinks you can adapt a new fvOption from

https://www.openfoam.com/documentati...urbSource.html and from https://www.openfoam.com/documentati...urbSource.html

Originally Posted by ali moeni

Hi there, did you find any solution?

[veronicagillis]

Originally Posted by MMRC

Hello,

For canopy sources/sinks you can adapt a new fvOption from

https://www.openfoam.com/documentati...urbSource.html and from https://www.openfoam.com/documentati...urbSource.html geometry dash lite

You can indeed use fvOptions to add a constant source term to the concentration equation. In your case, you would create an fvOptions file for the concentration equation. Here is an example:

plaintext
Copy code
dimensions [0 0 -2 0 0 0 0];

inletFractionSource
{
// Specify the regions where the source term should be active
selectionMode all;

// Specify the field to which the source term should be added
fields (C);

// Specify the value of the constant source term
CSource 100; // Adjust the value as needed

// Relaxation factor (if needed)
relaxation 1.0;
}
This fvOptions file adds a constant source term to the concentration equation (C field) in the specified regions.