[bieshuxuhe]

hi !
In pimpleFoam/createFields.H , there is a line of code :

singlePhaseTransportModel laminarTransport(U, phi);

I think that code means reading transportProperties ! So I check it in the source guide , there is :

31 // * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
32 
33 Foam::singlePhaseTransportModel::singlePhaseTransportModel
34 (
35  const volVectorField& U,
36  const surfaceScalarField& phi
37 )
38 :
39  transportModel(U, phi),
40  viscosityModelPtr_(viscosityModel::New("nu", *this, U, phi))  
41 {}
42 


31 // * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
32 
33 Foam::transportModel::transportModel
34 (
35  const volVectorField& U,
36  const surfaceScalarField& phi
37 )
38 :
39  IOdictionary
40  (
41  IOobject
42  (
43  "transportProperties",
44  U.time().constant(),
45  U.db(),
46  IOobject::MUST_READ_IF_MODIFIED,
47  IOobject::NO_WRITE
48  )
49  )
50 {}

please note the red "*this" , "this" pointer should point to the object of "singlePhaseTransportModel class" ! so the "*this" is the laminarTransport ,but the New() function need a dictionary not a singlePhaseTransportModel ! look down the code:

Foam::autoPtr<Foam::viscosityModel> Foam::viscosityModel::New
(
    const word& name,
    const dictionary& viscosityProperties,
    const volVectorField& U,
    const surfaceScalarField& phi
)
{
    const word modelType(viscosityProperties.lookup("transportModel"));

    Info<< "Selecting incompressible transport model " << modelType << endl;

    dictionaryConstructorTable::iterator cstrIter =
        dictionaryConstructorTablePtr_->find(modelType);

    if (cstrIter == dictionaryConstructorTablePtr_->end())
    {
        FatalErrorIn
        (
            "viscosityModel::New(const volVectorField&, "
            "const surfaceScalarField&)"
        )   << "Unknown viscosityModel type "
            << modelType << nl << nl
            << "Valid viscosityModels are : " << endl
            << dictionaryConstructorTablePtr_->sortedToc()
            << exit(FatalError);
    }

    return autoPtr<viscosityModel>
        (cstrIter()(name, viscosityProperties, U, phi));
}

I know that the singlePhaseTransportModel is a multiplely derived class from dictionary class ! is it why we can regard singlePhaseTransportModel as a dictionary when using New()?

thanks!

[alexeym]

Hi,

Yes.

class transportModel
:
    public IOdictionary
{
...
}

Foam::transportModel::transportModel
(
    const volVectorField& U,
    const surfaceScalarField& phi
)
:
    IOdictionary
    (
        IOobject
        (
            "transportProperties",
            U.time().constant(),
            U.db(),
            IOobject::MUST_READ_IF_MODIFIED,
            IOobject::NO_WRITE
        )
    )
{}

[bieshuxuhe]

Thanks for your reply !
runTimeSelection mechanism is so beautiful !
so is the objectRegistry.

[bagherij]

Hi
I am working on creeping flow (non- Newtonian steady),i used simple foam with a viscosity model ,i need to use kinematic viscosity
(nu(), which returned from viscosity model) to calculate shear stress ,how can i use nu in a utility or a function?i modify the utility "stresscomponent.C" as follow but this message coming
"nu is not declared in this scope"
code:
#include "fvCFD.H"
#include "incompressible/singlePhaseTransportModel/singlePhaseTransportModel.H"
#include "zeroGradientFvPatchFields.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

int main(int argc, char *argv[])
{
timeSelector::addOptions();

# include "setRootCase.H"
# include "createTime.H"

instantList timeDirs = timeSelector::select0(runTime, args);

# include "createMesh.H"

forAll(timeDirs, timeI)
{
runTime.setTime(timeDirs[timeI], timeI);

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

IOobject Uheader
(
"U",
runTime.timeName(),
mesh,
IOobject::MUST_READ
);

// Check U exists
if (Uheader.headerOk())
{
mesh.readUpdate();

Info<< " Reading U" << endl;
volVectorField U(Uheader, mesh);

# include "createPhi.H"

singlePhaseTransportModel laminarTransport(U, phi);

volScalarField strainRate
(
IOobject
(
"strainRate",
runTime.timeName(),
mesh,
IOobject::NO_READ
),
nu()*sqrt(2.0f)*mag(symm(fvc::gra d(U))) //this command will calculate strainRate
);
strainRate.write();//this will write file "StrainRate" in each time dir!!

}
else
{
Info<< " No U" << endl;
}

Info<< endl;
}

Info<< "End" << endl;

return 0;
}

best regards
jafar