[Gareth_CN]

Hello,

I am newbie to OpenFOAM. I am using OpenFOAM v8.

I would like to code a new BC which couples `timeVaryingMappedFixedValue` BC and `inletOutlet` BC. After interpolating the values from a set of supplied points in space and time, the typs of BC ('into of domain' or 'out of domain' ) would be determined by the sign of the flus across patch faces.

- Positive flux (out of domain): apply zero-gradient condition
- Negative flux (into of domain): apply the interpolation values as fixed-value

The new BC, named 'timeVaryingInletOutlet' can be well compiled. But I get the error message as belows when I run "decomposePar" on a test case based on pimpleFoam:

--> FOAM FATAL ERROR:
    request for surfaceScalarField phi from objectRegistry region0 failed
    available objects of type surfaceScalarField are 0()

    From function const Type& Foam::objectRegistry::lookupObject(const Foam::word&) const [with Type = Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh>] in file /home/gareth/OpenFOAM/OpenFOAM-8/src/OpenFOAM/lnInclude/objectRegistryTemplates.C at line 211.

It seems that the flux `phi ` of type surfaceScalarField cannot not be found. I have examined the source file `createFields.H` which contains the call to `createPhi.H` (I did not modify this file).

I have searched for relevant problems on this forum, but I have not found a solution to my case.

Here is the `updateCoeffs` function of myCode, which is related to flux:

template<class Type>
void Foam::timeVaryingInletOutletFvPatchField<Type>::updateCoeffs()
{
    if (this->updated())
    {
        return;
    }
   this->operator==(fieldMapper_.map());
// copied from the source file of  'inletOutlet' boundary
    const Field<scalar>& phip =
        this->patch().template lookupPatchField<surfaceScalarField, scalar>
        (
            phiName_
        );
    this->valueFraction() = 1.0 - pos0(phip);
//
    fixedValueFvPatchField<Type>::updateCoeffs();
}

Line 211 of `objectRegistryTemplates.C`:

        FatalErrorInFunction
            << nl
            << "    request for " << Type::typeName
            << " " << name << " from objectRegistry " << this->name()
            << " failed\n    available objects of type " << Type::typeName
            << " are" << nl
            << names<Type>();

        if (cacheTemporaryObject(name))
        {
            FatalErrorInFunction
                << nl
                << "    request for " << name << " from objectRegistry "
                << this->name() << " to be cached failed" << nl
                << "    available temporary objects are" << nl
                << temporaryObjects_;
        }
        FatalErrorInFunction                 // line 211
            << abort(FatalError);            // line 212
    }
    return NullObjectRef<Type>();

Maybe I made some stupid mistake. Hope someone could give me some advice！

All regards!

Gareth