[nskelly]

Hi,

I have been using foam-extend 3.2 to perform some simulations and have come into some problems with meshing and solving.

Just to note, I have used this exact same mesh and boundary conditions in OF 5 and did not receive any of the following problems.

It is a simple backward facing step geometry with inlet, outlet, upperwall and lowerwall, front and back.

I want to apply cyclic boundary conditions to the front and back but when meshing I get errors regarding the face areas do not match. I also tested this out on the pitzDaily tutorial and the same problem occurred.

Searching forums showed that using cyclicAMI helps with this problem, and it did and I was able to create a mesh fine.

However, when I apply boundary conditions using cyclicAMI and trying to solve the case I get the following error.

--> FOAM FATAL ERROR:

    gradientInternalCoeffs cannot be called for a genericFvPatchField (actual type cyclicAMI)
    on patch front of field U in file "/data1/foam/nk583-3.2/bfs_test/locDynEddy_visco/0/U"
    You are probably trying to solve for a field with a generic boundary condition.

    From function genericFvPatchField<Type>::gradientInternalCoeffs() const
    in file fields/fvPatchFields/basic/generic/genericFvPatchField.C at line 811.

FOAM exiting

0/U:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | foam-extend: Open Source CFD                    |
|  \\    /   O peration     | Version:     3.2                                |
|   \\  /    A nd           | Web:         http://www.foam-extend.org         |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volVectorField;
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 1 -1 0 0 0 0];

internalField   uniform (0 0 0);

boundaryField
{
    inlet
    {
        type            turbulentInlet;
        referenceField  uniform (0.75 0 0);
        fluctuationScale (0.02 0.01 0.01);
        value           uniform (0.75 0 0);
    }

    outlet
    {
        type            inletOutlet;
        inletValue      uniform (0 0 0);
        value           uniform (0 0 0);
    }

    upperWall
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }

    lowerWall
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }

    front
    {
        type            cyclicAMI;
        value           $internalField;
    }

    back
    {
        type            cyclicAMI;
        value           $internalField;
    }

}

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

Any ideas what this error refers to?

Thanks in advance!

[tomf]

Hi,

With foam-extend you need to use GGI instead of AMI, they are similar as they allow for nonconformal interfaces, but the implementation differs between them. Please have a look into tutorials for GGI with foamExtend.

Regards,
Tom

[nskelly]

Hi,

I have just tried to use the cyclicGGI BC and I receive the same error.

I'm not sure how to find tutorials in foam-extend as foamSearch command does not work. Do you know of any tutorials that specifically use cyclicGGI?

I also don't understand why the basic cyclic BC does not work for such a simple geometry.

Thanks

[tomf]

Hi,

It is called ggi in foam-extend, not cyclicGGI, so that is why you have the error, which basically says that the name cyclicGGI/cyclicAMI is not known to foam-extend.

You can find some tutorials like this:

grep -r ggi $FOAM_TUTORIALS

from a terminal.

Then you just need to find the one that is closest to your problem.

Regards,
Tom

[nskelly]

Hi,

Using ggi seems work, although I do not exactly know what it does that 'cyclic' cannot.

The tutorial cases helped!

Thanks for the help!

[Gang Wang]

Hi!

Thanks for your nice thread about this issue. I'd like to know how do you set up your back and front surface "transform" type? I feel quite puzzled when setting this, not sure whether "translational" or "noOrdering".

Best,

Gang

Originally Posted by nskelly

Hi,

Using ggi seems work, although I do not exactly know what it does that 'cyclic' cannot.

The tutorial cases helped!

Thanks for the help!