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Adding Boussinesq Approximation to multiphaseInterFoam?

Hello,

I don't kown how to code well in C++ but I'm trying to implement the Boussinesq approximation into the multiphaseInterFoam Solver (OF 4.0). I have succeeded yet with interFoam.

I added a file, T.Eqn with temperature equation and it compiles.

I have trouble with the Boussinesq term, I don't how to deal with it, I tried this in multiphaseMixture.C :

Code:

Foam::tmp<Foam::volScalarField>

Foam::multiphaseMixture::rhoB() const

{

    const volScalarField& T = U_.mesh().lookupObject<volScalarField>("T");

    PtrDictionary<phase>::const_iterator iter = phases_.begin();



    tmp<volScalarField> trhoB = iter()*(iter().rho()*(1.0-iter().beta()*(T-iter().Tref())));

    volScalarField& rhoB = trhoB.ref();



   for (++iter; iter != phases_.end(); ++iter)

  {

        rhoB += iter()*(iter().rho()*(1.0-iter().beta()*(T-iter().Tref())));

   }



  return trhoB;

}





Foam::tmp<Foam::scalarField>

Foam::multiphaseMixture::rhoB(const label patchi) const

{

   PtrDictionary<phase>::const_iterator iter = phases_.begin();



    tmp<scalarField> trhoB = iter().boundaryField()[patchi]*(iter().rho()*(1.0-iter().beta()*(T-iter().Tref())));

  scalarField& rhoB = trhoB.ref();



  for (++iter; iter != phases_.end(); ++iter)

   {

     rhoB += iter().boundaryField()[patchi]*(iter().rho()*(1.0-iter().beta()*(T-iter().Tref())));

   }



  return trhoB;

}

and in multiphaseMixture.H, I add :

Code:

      



  //- Return the mixture variable density 

       tmp<volScalarField> rhoB() const;   ////



        //- Return the mixture variable density for patch

        tmp<scalarField> rhoB(const label patchi) const;  ////

rhoB being rho0*(1-beta(T-Tref))

I have this error :
multiphaseMixture.C: In member function ‘Foam::tmp<Foam::Field<double> > Foam::multiphaseMixture::rhoB(Foam::label) const’:
multiphaseMixture.C:233:96: error: no match for ‘operator-’ (operand types are ‘<unresolved overloaded function type>’ and ‘const dimensionedScalar {aka const Foam::dimensioned<double>}’)
tmp<scalarField> trhoB = iter().boundaryField()[patchi]*(iter().rho()*(1.0-iter().beta()*(T-iter().Tref())));
~^~~~~~~~~~~~~~

I don't know how and where define rhoB and T.

Thanks !

I dont know multiphaseInterFoam but,

There is no rho in buoyancy term. You need to define g(if its not defined in your solver) - beta and Tref in create fields, they are transport properties.

g is vector, beta and Tref are scalars. After that you can add following line to your momentum equation.

Code:

- (g * beta * (T-Tref) )

Quote:

Originally Posted by Alona (Post 746039)

Code:

Foam::tmp<Foam::volScalarField>

Foam::multiphaseMixture::rhoB() const

{

    const volScalarField& T = U_.mesh().lookupObject<volScalarField>("T");

    PtrDictionary<phase>::const_iterator iter = phases_.begin();



    tmp<volScalarField> trhoB = iter()*(iter().rho()*(1.0-iter().beta()*(T-iter().Tref())));

    volScalarField& rhoB = trhoB.ref();



   for (++iter; iter != phases_.end(); ++iter)

  {

        rhoB += iter()*(iter().rho()*(1.0-iter().beta()*(T-iter().Tref())));

   }



  return trhoB;

}





Foam::tmp<Foam::scalarField>

Foam::multiphaseMixture::rhoB(const label patchi) const

{

   PtrDictionary<phase>::const_iterator iter = phases_.begin();



    tmp<scalarField> trhoB = iter().boundaryField()[patchi]*(iter().rho()*(1.0-iter().beta()*(T-iter().Tref())));

  scalarField& rhoB = trhoB.ref();



  for (++iter; iter != phases_.end(); ++iter)

   {

     rhoB += iter().boundaryField()[patchi]*(iter().rho()*(1.0-iter().beta()*(T-iter().Tref())));

   }



  return trhoB;

}

and in multiphaseMixture.H, I add :

Code:

      



  //- Return the mixture variable density 

       tmp<volScalarField> rhoB() const;   ////



        //- Return the mixture variable density for patch

        tmp<scalarField> rhoB(const label patchi) const;  ////

Hi Alona,
I'm trying to include Boussinesq approximation in interFoam but have some trouble in pressure Eqn. If you are interested, I can share the code or send you an email regarding this.

Many thanks,
Gowthaman