[subhojitkadiacfd]

Hi all,
How can I introduce a boundary condition of a variable as a function of another variable. Lets say, how can I introduce the following boundary condition:
epsilon=0.391*k*y*z
Thanking you.
Subhojit

[Tobermory]

Simplest would be to use the funkSetBoundaryField utility, but you want to do it with codeStream, so here's how. Use a fixedValue type for the epsilon boundary patch you are interested in (here I will assume that this patch is called "inlet"), and put this for the value:

inlet
{
   type    fixedValue;
   value   #codeStream {
               codeInclude #{ #include "fvCFD.H" #};
               codeOptions  #{ -I$(LIB_SRC)/finiteVolume/lnInclude -I$(LIB_SRC)/meshTools/lnInclude #};
               codeLibs #{ -lfiniteVolume -lmeshTools #};
               code #{
                  const IOdictionary& d = static_cast<const IOdictionary&>(dict.parent().parent());
                  const fvMesh& mesh = refCast<const fvMesh>(d.db());
                  const label id = mesh.boundary().findPatchID("inlet");
                  const fvPatch& patch = mesh.boundary()[id];
                  scalarField epsp(patch.size(), 0.0);

                  const volScalarField& k = mesh.lookupObject<volScalarField>("k");
                  const scalarField& kp = k.boundaryField()[id];

                  forAll(epsp, facei)
                  {
                     const scalar y = patch.Cf()[facei].y();
                     epsp[facei] = 0.391*kp[facei]*y;
                  }
                  writeEntry(os, "", epsp);
               #};
            };
    }

Note the footwork that's required to find the patch, and to get references to the mesh and other fields. Good luck!

[subhojitkadiacfd]

Many thanks. It shows dict is not defined. How to remove it?