[CHARLES]

Hello all,

After a solid 8 hours of trying to figure this out, I have come to you... again I have tried just about everything I could think of and I cannot figure it out so I would really appreciate it if someone could please help me.

I would like the forAll loop to assign a value to alphad_ for the corresponding cell, depending on the value of alphadCheck_ for the same cell.

When I run simpleFoam and use the 'sample' utility, I can see that alphadCheck_ is a really small value (1.2732e-313) at the first cell, then it is equal to 0 for the rest of the domain (see sample outputs attached)... HOWEVER, alphad_ is being assigned the latter value from the if statement (see code below) for ALL of the domain when it should really be assigned the first since alphadCheck_=0.
I know that alphadCheck_ should be 0 for the freestream but it shouldn't be so for the whole domain.

In the .H file, I have defined alphad_ and alphadCheck_ as volScalarField under 'protected:'

In the .C file, I have defined alphad_ and alphadCheck_ as

alphad_
    (
        IOobject
        (
            "alphad_",
            runTime_.timeName(),
            mesh_,
            IOobject::NO_READ,
            IOobject::AUTO_WRITE
        ),
        mesh_,
        dimless
    ),
 alphadCheck_ 
    (
        IOobject
        (
            "alphadCheck_",
            runTime_.timeName(),
            mesh_,
            IOobject::NO_READ,
            IOobject::AUTO_WRITE
        ),
        mesh_,
        dimensionSet(0,0,-3,0,0,0,0)
    )

This is the part from my .C file that isn't working (the .C is attached too)

volScalarField alphadCheck_(fvc::grad(k_) & fvc::grad(omega_));  

forAll(mesh_.cells(),celli)
{    
    if (alphadCheck_[celli] <= 0.0)
    {
    alphad_[celli]=scalar(0.0);
    }if (alphadCheck_[celli] > 0.0)
    {
    alphad_[celli]=scalar(0.125);
    }
}

I tried defining alphadCheck_ as 'const volScalarField& alphadCheck_(fvc::grad(k_) & fvc::grad(omega_));' and that caused the following error:

#0  Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam220/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#1  Foam::sigSegv::sigHandler(int) in "/opt/openfoam220/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#2   in "/lib/x86_64-linux-gnu/libc.so.6"
#3  Foam::incompressible::RASModels::kOmega2006C12::correct() in "/home/sebastian/OpenFOAM/sebastian-2.2.0/platforms/linux64GccDPOpt/lib/libmyIncompressibleRASModels.so"
#4  
 in "/opt/openfoam220/platforms/linux64GccDPOpt/bin/simpleFoam"
#5  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#6  
 in "/opt/openfoam220/platforms/linux64GccDPOpt/bin/simpleFoam"
Segmentation fault (core dumped)
sebastian@navier1:~/OpenFOAM/sebastian-2.2.0/run/FlatPlates/New/545kOm2006P112$

I also tried changing the second 'if' for an 'else' and it made no difference.

Thank you for your help... I've been stuck on this for a month and have nobody to ask questions to!

[Bernhard]

Does this code compile even?

I am asking this, because you use
> volScalarField alphadCheck_(fvc::grad(k_) & fvc::grad(omega_));

While alphadCheck_ is, according to your source file, already initialized during construction, so, you would need, instead
> alphadCheck_ = (fvc::grad(k_) & fvc::grad(omega_));

I don't see any problem with your loop, although I would write
> forAll( alphad_, cellI)
just because it looks nicer, as it clear shows what object you are looping.

You probably don't even need a loop for this, as there is probably a single expresion alphad_ = ... that would work.

[CHARLES]

Thank you for replying !

The code compiles and runs... it just doesn't run right.

Whenever I try your suggestion and get rid of 'volScalarField' (right before the for loop) and define alphad_ as just

alphadCheck_ = (fvc::grad(k_) & fvc::grad(omega_));

,
I get a compile error:

kOmega2006C12.C:351:47: error: no match for call to ‘(Foam::volScalarField {aka Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh>}) (Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> >)’

When I try to get rid of the for loop and use:

if (alphadCheck_ <= 0.0)
    {
    alphad_=scalar(0);
    }else 
    {
    alphad_=scalar(0.125);
    }

I get another compile error:

kOmega2006C12.C: In member function ‘virtual void Foam::incompressible::RASModels::kOmega2006C12::correct()’:
kOmega2006C12.C:365:22: error: no match for ‘operator<=’ in ‘alphadCheck_ <= 0.0’
kOmega2006C12.C:365:22: note: candidates are:
/opt/openfoam220/src/OpenFOAM/lnInclude/UList.C:224:6: note: bool Foam::UList<T>::operator<=(const Foam::UList<T>&) const [with T = double]
/opt/openfoam220/src/OpenFOAM/lnInclude/UList.C:224:6: note:   no known conversion for argument 1 from ‘double’ to ‘const Foam::UList<double>&’
/opt/openfoam220/src/OpenFOAM/lnInclude/VectorSpaceI.H:693:13: note: template<class Form, class Cmpt, int nCmpt> bool Foam::operator<=(const Foam::VectorSpace<Form, Cmpt, nCmpt>&, const Foam::VectorSpace<Form, Cmpt, nCmpt>&)
make: *** [Make/linux64GccDPOpt/kOmega2006C12.o] Error 1

PS:I took your advice on not using a for loop in the other instance (from a different post) and it helped clean up the code. Thank you!

[Bernhard]

Ah, you need to remove the brackets (sorry for misleading:
> alphadCheck_ = fvc::grad(k_) & fvc::grad(omega_);

This if-statement is wrong, because you are comparing fields with scalars. I think function like min, max, bound are designed to handle fields and scalars as arguments, but this is something you have to find.

[CHARLES]

That worked. You are the man! Thank you very much.

I ended up just leaving the for loop for now.


Could you explain why what I was doing was causing problems?
I'm quite new to modifying OpenFOAM so I don't really understand how removing the brackets or volScalarField solved the problem... I just know that it did.

[Bernhard]

It does not really OpenFOAM, but just regular C++.

i.e:

$ cat test.c
int main()
{
    int a(10);
    int a(10);
}
$ g++ test.c
test.c: In function 'int main()':
test.c:4: error: redeclaration of 'int a'
test.c:3: error: 'int a' previously declared here

Apparently, the other one calls a nameless function (see also the error message). My C++ knowledge is not that developed, but I think it calls the "()" operator of the type volScalarField (since Foam:) is probably not defined), which does not accept the given arguments. I am very unsure about this, so I hope some-one can correct/confirm something here

[CHARLES]

Gotcha! Thank you again for helping me out.