[M.Davoodi]

Hi Guys,
I was looking at the constrainHbyA.C file and there are two parts that seems to me really odd, I was wondering if someone with more experience can give me some feedback? What happens on the red part? It calls for pressure at the boundary and then it does nothing? No variable has been changed or modified here....
What about the blue part, it says HbyA at boundary is equal to velocity value at the boundary?! That is odd, really doesn't make much sense to me...

,


\*---------------------------------------------------------------------------*/
27
28 #include "constrainHbyA.H"
29 #include "volFields.H"
30 #include "fixedFluxExtrapolatedPressureFvPatchScalarField.H "
31
32 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
33
34 Foam::tmp<Foam::volVectorField> Foam::constrainHbyA
35 (
36 const tmp<volVectorField>& tHbyA,
37 const volVectorField& U,
38 const volScalarField& p
39 )
40 {
41 tmp<volVectorField> tHbyANew;
42
43 if (tHbyA.isTmp())
44 {
45 tHbyANew = tHbyA;
46 tHbyANew.ref().rename("HbyA");
47 }
48 else
49 {
50 tHbyANew = new volVectorField("HbyA", tHbyA);
51 }
52
53 volVectorField& HbyA = tHbyANew.ref();
54 volVectorField::Boundary& HbyAbf = HbyA.boundaryFieldRef();
55
56 forAll(U.boundaryField(), patchi)
57 {
58 if
59 (
60 !U.boundaryField()[patchi].assignable()
61 && !isA<fixedFluxExtrapolatedPressureFvPatchScalarFie ld>
62 (
63 p.boundaryField()[patchi]
64 )
65 )
66 {
67 HbyAbf[patchi] = U.boundaryField()[patchi];
68 }
69 }
70
71 return tHbyANew;
72 }