[rres]

Well,

1) yes, i found it somewhere.

2) reading another example carefully, I realize that faceCentreshub was not a class, but a variable that needs to be declared.const fvPatchVectorField& faceCentreshub = mesh.Cf().boundaryField()[inletPatchID]; should do the trick.

3) I think the problem was in createFields.H, where the fields are actually created/declared.
Adding the following lines and I think it's ok:

Info << "Reading field k\n" << endl;
volScalarField k
(
IOobject
(
"k",
runTime.timeName(),
mesh,
IOobject::MUST_READ,
IOobject::AUTO_WRITE
),
mesh
);

Info << "Reading field Epsilon\n" << endl;
volScalarField epsilon
(
IOobject
(
"epsilon",
runTime.timeName(),
mesh,
IOobject::MUST_READ,
IOobject::AUTO_WRITE
),
mesh
);

Ravi