CFD Online Discussion Forums - multi region case - access field from another region

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multi region case - access field from another region

dear all!

i modified chtMultiRegionFoam including a radiation model in the fluid region. the radiation model, or better the BC of the radiation model, calculates a radiative wall heat flux Qr at every boundary and writes it out at the specified time steps.

now i need to access Qr from the solid region, i.e. in the forAll(solidRegions, i)-loop (see solvers/heatTransfer/chtMultiRegionFoam/chtMultiRegionFoam.C line 104) .

first i tried to create a IOobject QrFluid in creatFluidFields with the MUST_READ option. but as it isn t updated in the code (and for now I don t know how to do it) it doesn t read the actual Qr field.

i also tried to use the db().lookupobject<> function which returns a reference to the object registry like:

Code:

const volScalarField& QrFluid = UFluid[j].db().lookupObject<volScalarField>("Qr");

but without success. the code compiles but throws the error message below when executed:

Code:

--> FOAM FATAL ERROR: 

hanging pointer, cannot dereference



    From function PtrList::operator[] const

    in file /opt/openfoam171/src/OpenFOAM/lnInclude/PtrListI.H at line 108.



FOAM aborting



#0  Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam171/lib/linux64GccDPOpt/libOpenFOAM.so"

#1  Foam::error::abort() in "/opt/openfoam171/lib/linux64GccDPOpt/libOpenFOAM.so"

#2  

 in "/home/aa/OpenFOAM/aa-1.7.1/applications/bin/linux64GccDPOpt/yazdRadBC"

#3  

 in "/home/aa/OpenFOAM/aa-1.7.1/applications/bin/linux64GccDPOpt/yazdRadBC"

#4  __libc_start_main in "/lib/libc.so.6"

#5  

 in "/home/aa/OpenFOAM/aa-1.7.1/applications/bin/linux64GccDPOpt/yazdRadBC"

Aborted

does anybody have an idea how to access the fluid field Qr from the solid region?

i greatly appreciate your comments!
thx in advance!!
aram

Quote:

Originally Posted by mabinty (Post 322538)

Code:

const volScalarField& QrFluid = UFluid[j].db().lookupObject<volScalarField>("Qr");

but without success. the code compiles but throws the error message below when executed:

Code:

--> FOAM FATAL ERROR: 

hanging pointer, cannot dereference



    From function PtrList::operator[] const

    in file /opt/openfoam171/src/OpenFOAM/lnInclude/PtrListI.H at line 108.



FOAM aborting



#0  Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam171/lib/linux64GccDPOpt/libOpenFOAM.so"

#1  Foam::error::abort() in "/opt/openfoam171/lib/linux64GccDPOpt/libOpenFOAM.so"

#2  

 in "/home/aa/OpenFOAM/aa-1.7.1/applications/bin/linux64GccDPOpt/yazdRadBC"

#3  

 in "/home/aa/OpenFOAM/aa-1.7.1/applications/bin/linux64GccDPOpt/yazdRadBC"

#4  __libc_start_main in "/lib/libc.so.6"

#5  

 in "/home/aa/OpenFOAM/aa-1.7.1/applications/bin/linux64GccDPOpt/yazdRadBC"

Aborted

does anybody have an idea how to access the fluid field Qr from the solid region?

i greatly appreciate your comments!
thx in advance!!
aram

Funny, I am also hacking on the same solver, and had the same error yesterday. In my case, I traced the error with print statements to

Code:

        radiation.set

        (

            i,

            radiation::radiationModel::New(thermoFluid[i].T())

        );

in createFluidFields.H. It turned out that thermoFluid was not initialized. I had to prepend

Code:

        thermoFluid.set

        (

            i,

            basicRhoThermo::New(fluidRegions[i]).ptr()

        );

So, my guess is that you don't have a variable declared/initialized.

Good luck,

Mirko

hey Mirko!

thanks a lot for your reply!!

the chtMRF code where i added a radiation and combustion model actually works. i found some troubles (= numerical instability) when taking the radiative heat flux Qr for the cht-BC into account. hence, i want to try a new approach where Qr is applied as source term in the solid.

the problem i described above happens cause i havn t understood yet how to dereference the fluid field pointer lists outside of the fluid-loop. the error message comes from:

Code:

/opt/openfoam171/src/OpenFOAM/lnInclude/PtrListI.H at line 108

in the operator[] because there seems to be no element in SOMTHING[i]:

Code:

if (!ptrs_[i])

    {

        FatalErrorIn("PtrList::operator[]")

            << "hanging pointer, cannot dereference"

            << abort(FatalError);

    }

the operator<< which writes to OStream works, hence

Code:

Info<< "QrFluid: " << UFluid[j].db().lookupObject<volScalarField>("Qr") 

    << endl;

shows me the Qr-volField i want.

any idea? i ll keep on digging and report!!

cheers,
aram

Aram,

OF2.0 chtMultiRegionFoam includes radiation.

As for debugging, my approach is to copy the relevant solver or BC to my user directories, compile them, and then start adding print/Info statements to narrow down the cause of the error.

Mirko