[ashishmagar600]

Hello everyone.

I was trying to impose a fixed velocity(cell by cell) to a cellZone, by using setValues from fvMatrix.

I created a labelList of cells from their IDs, however I am stuck as how to proceed further.

Can anyone help ..?

Thank you.

[ashishmagar600]

Anyway Solved..!!

[Michael@UW]

Originally Posted by ashishmagar600

Anyway Solved..!!

Dear Ashish,

Can you explain how you get it solved?

I use the following code to change the velocity if the cells are in the cylinder centered at a specific point. I observe the U is changed around the point but it is not 0 as specified.

I have been stuck in this for a while. Can you please point out the errors? Thanks in advance!

FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      fvOptions;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
codedSource
{
    type            vectorCodedSource;
    selectionMode   all;

    fields          (U);
    name            codedSource;
	
    codeConstrain
    #{  
                
        const vector& pt = vector(0.1, 0, 0.01) ;
        const vectorField center = mesh().C();

        labelList cells;

		forAll(center, i)
		{
			const vector ds = pt - center[i];
			scalar d = sqrt(ds.x() * ds.x() + ds.y() * ds.y());
			if (d <= 0.009)
			{

				Info << "I=" << i << endl;

				cells.append(i);                
			}    
		};

		vectorField values(cells.size());
		Info << "Cells selected: " << cells << endl;
		values = vector(0, 0, 0);
		eqn.setValues(cells, values);                 
    #};
    
    codeCorrect
    #{
    #};
    codeAddSup
    #{
    #};  
    code
    #{
            $codeInclude
            $codeCorrect
            $codeAddSup
            $codeSetValue
    #};
}

[ashishmagar600]

This was tricky. I did modify interFoam-> Ueqn.H as that suited my purpose.

I had to call setValues once again after the pressure correction was done and that solved my problem.

[Michael@UW]

Thank you for your reply! I guess the U field is corrected by the silver due to conservation. In my case, I tried to fix the velocities of a chunk of fluid cells which does not make sense in practice( just for testing). If I just fix one cell of some separate cells, it is possible to adjust the flow field to satisfy the mass and momentum conservation to fix the velocity at these cells.

So it makes sense you setValue again after the pressure correction which seems not possible in fvOptions.