[woodie]

Good day everybody,

I have a question concerning an error about requesting objects from the objectRegistry.
I get the following error when using decomposePar:

--> FOAM FATAL ERROR:

    request for incompressibleTurbulenceModel turbulenceProperties from objectRegistry region0 failed
    available objects of type incompressibleTurbulenceModel are
0()

    From function const Type& Foam::objectRegistry::lookupObject(const Foam::word&, bool) const [with Type = Foam::incompressibleTurbulenceModel]
    in file /home/cholzinger/OpenFOAM/OpenFOAM-v1912/src/OpenFOAM/lnInclude/objectRegistryTemplates.C at line 463.

I know it has something to do with the BC i have programmed for omega. It works perfectly fine with a standard BC, but with my custom BC, the error occurs (It occurs as well using other functions like renumberMesh, but i was able to work around that). So my understanding is, that when OpenFoam reads 0/omega, it tries to look up a turbulence model which ist not selected yet.

In the custom BC the Reynolds Stress Tensor is retrieved by something like that (in the .C-File):

	
// - Retrieve Reynolds Stress Tensor from Turbulence Model
const incompressibleTurbulenceModel& turbModel = db().lookupObject<incompressibleTurbulenceModel>
const tmp<volSymmTensorField> Re1 = turbModel.devReff();

In general, the custom BC is used with a custom turbulence model (slightly modified SSTLM) to model surface roughness and i use v1912.

Does anyone know a better way to program this, or a workaround so i can use functions which only read the 0-directory like decomposePar and renumberMesh?

Best regards
Christoph

[GerhardHolzinger]

Originally Posted by woodie

    
// - Retrieve Reynolds Stress Tensor from Turbulence Model
const incompressibleTurbulenceModel& turbModel = db().lookupObject<incompressibleTurbulenceModel>
const tmp<volSymmTensorField> Re1 = turbModel.devReff();

Christoph

I see a difference between your code and OpenFOAM-v1912 in the way the turbulence model is fetched from the object registry:

    const turbulenceModel& turbModel = db().lookupObject<turbulenceModel>
    (
        IOobject::groupName
        (
            turbulenceModel::propertiesName,
            internalField().group()
        )
    );

This may or may not be the cause of the error, however the standard omegaWallFunction BC does it this way.

[woodie]

Thanks for your quick response.

The reason for that difference is that i need to access defReff to compute the wall shear stress. And i only managed to do that through the incompressibleTurbulenceModel class.

[GerhardHolzinger]

Two problems:

1. Assuming that looking-up the turbulenceModel is always possible.
This causes the error when running decomposePar. Pre-processing utilities generally do not create a turbulence model. Hence, when the BC is constructed, there is no turbulenceModel for the BC to look-up.

    // check if there is a turbulence model in the object registry
    //  this is the case when the solver runs the case
    //  this is not the case when we do pre-processing
    if
    (
        db().found
        (
            IOobject::groupName
            (
                turbulenceModel::propertiesName,
                internalField().group()
            )
        )
    )
    {
        // get the turbulence model from the object registry
        //  this returns the base class
        const turbulenceModel& turbModel = db().lookupObject<turbulenceModel>
        (
            IOobject::groupName
            (
                turbulenceModel::propertiesName,
                internalField().group()
            )
        );

        // do what you intend to do here

    }

2. Using/relying on methods that are provided by some classes further down the family tree.
This was the reases why you looked up incompressibleTurbulenceModel instead of turbulenceModel. While this is technically not wrong, it would be safer and better form () to look up the base class, i.e. the root of the family tree (of class inheritance); and then check whether the looked-up turbulence model is acutally an incompressible one. If this is the case, you can do a type-cast, which then provides you all the methods you intend to use.

        // check whether the turbulence model is an incompressible one
        if (isA<incompressibleTurbulenceModel>(turbModel))
        {
            // get a reference to the incompressible turbulence model by doing a refCast
            //  now we have access to methods that the base class does not provide, e.g. devReff()
            const incompressibleTurbulenceModel& incompTurbModel = refCast<const incompressibleTurbulenceModel>(turbModel);
	        
	        // - Deviatoric Reynolds Stress Tensor at boundary patch
	        const tmp<volSymmTensorField> Re1 = incompTurbModel.devReff();
	        
	        // do what you intend to do here
	    }