[keepfit]

As the title says, without looping over all CFD cells, is there any way to set a scalar/vector field to a constant value?

For instance, if we want to reset some special Scalar/Vector volField to Zero at the beginning of every PISO loop, the straightforward method is:

for (int cell_id=0; cell_id<Number_AllCells; cell_id++)
 {
    Scalar_volField [cell_id] = 0.0;

    Vector_volField [cell_id].x() = 0.0;
    Vector_volField [cell_id].y() = 0.0;
    Vector_volField [cell_id].z() = 0.0;
 }

In my case, the number of CFD cells is about 300k~500k, the above method seems not very efficient. I checked the online code guide, did not find something like to assign zeroField() or oneField to existing volumetric fields:

Scalar_volField = zeroField();  // oneField();
Vector_volField = zeroField();  // oneField();

Any idea? I believe there must be some functions in OpenFoam similar to typical c++ vector: myVec = std::vector(myVec.size(), 0.0), which zeros the "myVector".

[olesen]

Originally Posted by keepfit

Any idea? I believe there must be some functions in OpenFoam similar to typical c++ vector: myVec = std::vector(myVec.size(), 0.0), which zeros the "myVector".

My first idea would be to look at the GeometricField header and see which assignment operators you find. Hint: around Lines 700 onwards you should find something.

[keepfit]

Originally Posted by olesen

My first idea would be to look at the GeometricField header and see which assignment operators you find. Hint: around Lines 700 onwards you should find something.

Thanks for the reply. Could you please elaborate how to use these operators to assign constant fields? For static fvMesh, I think we could create some fields that does not change over time (e.g. constVolField), and we can always assign it to existing fields:

myVolField = constVolField;

Nevertheless, sometimes I need to do the interface refinement between different phases, in this case, how can we assign some `const` fields with dynamic mesh?

 // Member Operators  // line 724 in GeometricField.H 

        //- Return a const-reference to the dimensioned internal field
        //  Useful in the formulation of source-terms for FV equations
        inline const Internal& operator()() const;

        void operator=(const GeometricField<Type, PatchField, GeoMesh>&);
        void operator=(const tmp<GeometricField<Type, PatchField, GeoMesh>>&);
        void operator=(const dimensioned<Type>&);

        void operator==(const tmp<GeometricField<Type, PatchField, GeoMesh>>&);
        void operator==(const dimensioned<Type>&);

        void operator+=(const GeometricField<Type, PatchField, GeoMesh>&);
        void operator+=(const tmp<GeometricField<Type, PatchField, GeoMesh>>&);

        void operator-=(const GeometricField<Type, PatchField, GeoMesh>&);
        void operator-=(const tmp<GeometricField<Type, PatchField, GeoMesh>>&);

        void operator*=(const GeometricField<scalar, PatchField, GeoMesh>&);
        void operator*=(const tmp<GeometricField<scalar,PatchField,GeoMesh>>&);

        void operator/=(const GeometricField<scalar, PatchField, GeoMesh>&);
        void operator/=(const tmp<GeometricField<scalar,PatchField,GeoMesh>>&);

        void operator+=(const dimensioned<Type>&);
        void operator-=(const dimensioned<Type>&);

        void operator*=(const dimensioned<scalar>&);
        void operator/=(const dimensioned<scalar>&);

[joshwilliams]

Originally Posted by keepfit

As the title says, without looping over all CFD cells, is there any way to set a scalar/vector field to a constant value?

Have you tried multiplying the field by 0? Then if you want to set it to one you can add one? I have done this a few times as a lazy way of initialising fields in post-processing tools.

[keepfit]

Originally Posted by joshwilliams

Have you tried multiplying the field by 0? Then if you want to set it to one you can add one? I have done this a few times as a lazy way of initialising fields in post-processing tools.

Good idea, I will give it a try on dynamic mesh.