CFD Online Discussion Forums - Calculating viscosity as a function of alpha

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Calculating viscosity as a function of alpha

Hello

I want to modify the thermoPhysicalModels library in a way that by changing alpha, viscosity change.
The problem is alpha should be read from mesh and mesh should be defined in defining mu.

The original mu definition that I want to change is located in

openfoam2006/src/thermophysicalModels/specie/transport/polynomial/polynomialTransportI.H

as follow:

Code:

template<class Thermo, int PolySize>

inline Foam::scalar Foam::polynomialTransport<Thermo, PolySize>::mu

(

    const scalar p,

    const scalar T

) const

{

    return muCoeffs_.value(T);

}

So I wan to change it to something like

Code:

template<class Thermo, int PolySize>

inline Foam::scalar Foam::polynomialTransport<Thermo, PolySize>::mu

(

    const scalar p,

    const scalar T

) const

{



const fvMesh& mesh;

const volScalarField& alphaL_ = mesh.lookupObject<volScalarField>("alpha.liquid");

scalar liquidVolume = fvc::domainIntegrate(alphaL_).value(); 



    return muCoeffs_.value(T)/liquidVolume;

}

It will be compiled, but the mesh must be initialized; without initialization, the solver will not work when we attempt to use it.

I looked at some other codes in openfoam and initializing mesh can be done by a code like

Code:

const fvMesh& mesh = alpha1_.mesh();

I tried

Code:

const fvMesh& mesh = this->mesh();

it is not working because this does not have a member named mesh, or .

Code:

const fvMesh& mesh = T.mesh();

which obviously wrong because T is scalar.

So any suggestion how I can initialize mesh here?

Hey,

I'm not sure if this will help you but this is how I would proceed:

This class is templated by a template class Thermo, the constructor of Thermo gets called in the initialisation list. The thermo s are obiously constructed with the input parameter "mesh", but there is no reference variable which stores the adress of mesh (which also means it wont get inherited). Thats where I think you have to go via one of the Field variables, because they store it (take a look at GeomtricField class)

I would try to get the mesh initialised by Thermo::T_.mesh() or by calling the return function Thermo.T().mesh().

I really hope that will help you, but I'm also kind of new in this field :o

Quote:

Originally Posted by aliyah. (Post 827640)

Code:

template<class Thermo, int PolySize>

inline Foam::scalar Foam::polynomialTransport<Thermo, PolySize>::mu

(

    const scalar p,

    const scalar T

) const

{

    return muCoeffs_.value(T);

}

So I wan to change it to something like

Code:

template<class Thermo, int PolySize>

inline Foam::scalar Foam::polynomialTransport<Thermo, PolySize>::mu

(

    const scalar p,

    const scalar T

) const

{



const fvMesh& mesh;

const volScalarField& alphaL_ = mesh.lookupObject<volScalarField>("alpha.liquid");

scalar liquidVolume = fvc::domainIntegrate(alphaL_).value(); 



    return muCoeffs_.value(T)/liquidVolume;

}

Code:

const fvMesh& mesh = alpha1_.mesh();

I tried

Code:

const fvMesh& mesh = this->mesh();

it is not working because this does not have a member named mesh, or .

Code:

const fvMesh& mesh = T.mesh();

which obviously wrong because T is scalar.

So any suggestion how I can initialize mesh here?

Quote:

Originally Posted by überschwupper (Post 827865)

I appreciate your ideas. I have tried both of your suggestions, but they are both unsuccessful. This is because neither Thermo nor the Thermo::T template class have access to mesh.