CFD Online Discussion Forums - Inject tracer within the simulation volume via fvOptions

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Inject tracer within the simulation volume via fvOptions

Hello everybody,

I am struggeling with fvOptions in OF2.3.x . I want to use a cellZone as a source of tracer T and solve the equations with scalarTransportFoam on a steady simpleFoam velocity field. I have tube and an obstacle, so I do not want to inject the tracer at the beginning of the tube but right before the obstacle. I want to use the source more or less as a internal "inlet-patch" for the tracer. Values should be 1 in the source and after a while in the whole domain after the source (just like with the fixedValue inlet BC for scalarTransportFoam).

I made the cellZone, set up the fvOptions file like this:

Code:

tracer

{

   type scalarSemiImplicitSource ;

   active on;

   timeStart 0;

   duration 10000;

   selectionMode cellZone;

   cellZone Tracer;



   scalarSemiImplicitSourceCoeffs

   {

      volumeMode absolute; //implicit

      injectionRateSuSp

      {

         T (1 0);

      }

   }

}

I end up with very high values of T around 5.4e4.

Is the source of 1 mole / itteration added to the domain every time step?

Can I set a fixedValue BC for fvOption like in inletBC?

Every help is thankfully appreciated. Thank you

Best regards,

Sebastian

FYI:

I managed the problem in a different way...

Copied the scalarTransportFoam and added the following:

Code:

    // Reading from the tracerInletDict from constant folder

    Info<< "\n*** Detecting injection Plane from tracerInletDict in control directory***\n" << endl;

    Info<< "Z position is " << z_position << endl;

    Info<< "Deviation is " << deviation << endl;



    // List to store the indices of the matching mesh.C()

    DynamicList<label> tracer_location(0);

    

    // Extract all Cells which are in the proper range

    forAll(mesh.C(), idx)

    {

      if (mesh.C()[idx].component(2) >= (z_position.value() - deviation.value()))

          if (mesh.C()[idx].component(2) <= (z_position.value() + deviation.value()))

          {

               tracer_location.append(idx);

          }

    }



    // solver loop

    while (simple.loop())

    {

        Info<< "Time = " << runTime.timeName() << nl << endl;

    

        while (simple.correctNonOrthogonal())

        { 

          // set the T value of proper cells to 1

          forAll(tracer_location,tracer_idx)

             {

                 T[tracer_location(tracer_idx)] = 1;

             }

            

            solve

            (

                fvm::ddt(T)

              + fvm::div(phi, T)

              - fvm::laplacian(DT, T)

             ==

                fvOptions(T)

            );

I have to open the question again...

My proposed solution worked fine on one core.
When I run the simulation on a HPC, I can not use my approach.

Does anybody have an idea how to run the code in parallel? Or an idea of a different solution?

Thanks a lot,

Best regards

Injecting a tracer from a patch inside a geometry

Hallo Foamers, i am new to OpenFoam, i am trying to calculate the RTD over a small section of porous media. This means that i have ti inject my tracer at some plane inside the geometry, to do this, i created an inside patch using topoSet and createBaffles, when i then impose the tracer inlet boundary condition on that boundary condition, my scalarTransportFoam simulation diverges within the first two timesteps. i read one thread mentioning the use of fvOptions, i have never used that before, i need help. While i am still at that. I am using OF9 and it got rid of fvOptions and introduced fvModels and fvConstraints instead. i need help on how i can set up my ksimulation to be able to inject this pulse tracer at an inside zone or patch

Best regards

Lucky