[chris Liu]

Hi, foamers:

I am a new OpenFOAM user, and i want to add a source term (body force) to icoFoam.

I creat a new field named "F" and add F to the N-S equation. After complie, i test it in the lid-driven-cavity example, and use the force on the lid to drive the fluid instead of the lid velocity. However, the fluid stay still and the force fill the cavity.(I want the force on the lid only and the fluid is driven.)

Any suggestions will be appreciated!
Best regards!
chris Liu

createFields.H
// add source term;
Info<< "Reading field F\n" << endl;
volVectorField F
(
IOobject
(
"F",
runTime.timeName(),
mesh,
IOobject::MUST_READ,
IOobject::AUTO_WRITE
),
mesh
);

icoFoam-force.C
fvVectorMatrix UEqn
(
fvm::ddt(U)
+ fvm::div(phi, U)
- fvm::laplacian(nu, U)

);

solve(UEqn == F -fvc::grad(p)); //add source term;


Detailed source file in the attachment.

[nakul]

Hi

If you need the force to be applied only on the lid then you have to define it as a boundary condition.

What you have done is that you have defined F as a volume field, i.e., on your mesh domain.

If you want to involve body force effects try buoyant solvers or define a new BC specific to your case.

[chris Liu]

Hi, nakul

Thank you for your advice!

I find that my expression was inconsistent.
The body force is a non-uniform field and depend on two factors, the distance to the patch and the orientation of the cell surface on the patch (e.g. lid). The body force (Lorentz force) is used to control the flow.

I will try the buoyant solves and post it here if i work it out.

Best regards
chris Liu

[Janez Turk]

Did it work?

how did you get incompressibility with body force?

LP Janez

[gironidegirona]

Hi chris Liu,

I'm trying to do the same thing, I want to add a source term into the transport equation. It is like a dragging force in the middle of the region.

I don't know how to implement that,

Can you give us a clue how you did it?

Thanks!