[juho]

I'd like to bother you all with a question again, sorry about it.

I've tried to update a boundary condition on each timestep based on values of the solution of the earlier steps.

The field I want to modify is a scalar and the boundary is defined as a uniform fixedValue.

I've tried to update it by including lines:

variable.boundaryField()[patchI] = newValue;
variable.correctBoundaryConditions();

in to the time loop. newValue is a scalar which is calculated on each timestep.

As many you must have noticed by now, it doesn't work. The values on the boundary patch don't change, even if the newValue changes.

What is the correct way to do this?

[eugene]

Try

variable.boundaryField()[patchI] == newValue;

The important bit is the double "==".

[juho]

Thank you!! Works perfectly!

I had given up on doing it in the solver was writing a boundary condition to do it.

[eugene]

Well doing it as a boundary condition is probably the "best" way of going about things.

Performing the assignment in the solver is a lot quicker to code though!

[tian]

Hi

"I've tried to update it by including lines:"

Can you give me an excample for the time loop? I also want to update the boundary condition for U after every iteration. I want use the bouyantSimpleFoam.

Thanks a lot

Bye
Thomas

[nsghaisas]

Hi Juho and Eugene

I want to implement a boundary condition that reads values from the previous time step and sets the gradient of another variable at the boundaries.

More specifically, I am trying to set the pressure gradient at the boundaries based on the temperature calculated in the previous time step.
dp/dz = g*beta*(T-Tref)

Could you giveme some pointers for doing that?

Thanks

Niranjan

[nsghaisas]

Hi Adam

Am I glad that you jumped in!

Thanks for these detailed instructions. Will try them out.

Thanks a lot.

Niranjan

[isabel]

Hello everybody,

I want to update a boundary condition called “ABAJO” on each timestep based on the values of the solution of the previous timestep. Particularty, I want to correct the variable T2=110*gamma.
I have written this code:

label inletPatchID = mesh.boundaryMesh().findPatchID("ABAJO");
fvPatchScalarField& condition = T2.boundaryField()[inletPatchID];
forAll(condition, patchI)
{
T2.boundaryField()[patchI] = 110*gamma.boundaryField()[patchI];
}
T2.correctBoundaryConditions();

The solver compiles Ok, but when I run the tutorial I have the following error:

#0 Foam::error:rintStack(Foam::Ostream&) in "/home/isabel/OpenFOAM/OpenFOAM-1.5/lib/linuxGccDPOpt/libOpenFOAM.so"
#1 Foam::sigSegv::sigSegvHandler(int) in "/home/isabel/OpenFOAM/OpenFOAM-1.5/lib/linuxGccDPOpt/libOpenFOAM.so"
#2 Uninterpreted: [0xb7766400]
#3 main in "/home/isabel/OpenFOAM/OpenFOAM-1.5/applications/bin/linuxGccDPOpt/17marzo5"
#4 __libc_start_main in "/lib/tls/i686/cmov/libc.so.6"
#5 _start at /build/buildd/glibc-2.9/csu/../sysdeps/i386/elf/start.S:122
Segmentation error

[pardoa]

Hello everyone,

This is an old post but maybe any of you can help me to solve the issue that I am currently facing.

I wish to turn into zero the values calculated by interFoam at the boundaries if alpha1 (water fraction) is lower than 0.1. I have managed to achieve this at the cells, but somehow I cannot make it at the boundaries.

Since OpenFOAM treats the internalFields and boundaryFields separately, I need also to convert the values of the cells and boundary faces whose alpha1 value is smaller than 0.1 into 0. Everything works for the internalFields:

    forAll(alpha1,i)
    {
        if (alpha1[i] < 0.1)
        {
            dSur[i] = 0.0;
            piezoSur[i] = 0.0;
            hSur[i] = 0.0;
        }
        else
        {
            dSur[i] = p[i]/(rho[i]*mag(gSur[i]));
            piezoSur[i] = dSur[i] + (meshSurface.C()[i].component(vector::Z)+zRef[i]);
            hSur[i] = ((0.5*magSqr(U[i]))/mag(gSur[i])) + dSur[i] + (meshSurface.C()[i].component(vector::Z)+zRef[i]);
        }
    }

But at the boundaries it does not:

    forAll (meshSurface.boundaryMesh(),patchID) 
    {
        forAll (meshSurface.boundaryMesh()[patchID],i) 
        {
            dSur.boundaryField()[patchID][i] = p.boundaryField()[patchID][i]/(rho.boundaryField()[patchID][i]*mag(gSur[patchID][i]));
        }
    }

This is the error that I am prompted with when I try to compile the code:

PHP Code:

./surface/solve_surfaceFlow.H: In function ‘int main(int, char**)’:
./surface/solve_surfaceFlow.H:65:132: error: assignment of read-only location &#8216;(&(& dSur.Foam::GeometricField<Type, PatchField, GeoMesh>::boundaryField<double, Foam::fvPatchField, Foam::volMesh>())->Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh>::Boundary::<anonymous>.Foam::FieldField<Foam::fvPatchField, double>::<anonymous>.Foam::PtrList<Foam::fvPatchField<double> >::<anonymous>.Foam::UPtrList<T>::operator[]<Foam::fvPatchField<double> >(patchID))->Foam::fvPatchField<double>::<anonymous>.Foam::Field<double>::<anonymous>.Foam::List<double>::<anonymous>.Foam::UList<T>::operator[]<double>(i)’
             dSur.boundaryField()[patchID][i] = p.boundaryField()[patchID][i]/(rho.boundaryField()[patchID][i]*mag(gSur[patchID][i])); 


Could anyone help to me figure out what I am doing wrong? I have also try with boundaryFieldRef. Then the code compiles but the simulation crashes at the very beginning.

Any help will be greatly welcomed!

Thanks!