CFD Online Discussion Forums - CHTC-based source term

Hello,

I'm trying to implement a convective heat transfer coefficient based source term for the energy equation of an incompressible heat transfer solver.

The equation I wish to implement would be the following :

$\frac{\partial T}{\partial t}+u_{j}\frac{\partial T}{\partial x_{j}}=\frac{\partial}{\partial x_{i}}(\alpha_{eff}\frac{\partial T}{\partial x_{j}})+\frac{hS(T_{w}-T)}{\rho_{0}C_{p}V}$

To do this, I modified the createFields.H of my solver to implement two volScalarFields, h and Tw.

To avoid taking into account the thermal contribution of the wall twice, alphaEff would be set to zero at the wall, and h and Tw set to zero anywhere but at the wall.

To implement this source term, I looked at fvOptions(T), however I could not find a way of implementing non-constant semi-implicit coefficients for the source term, thus I tried to implement it this way :

Code:





    fvScalarMatrix TEqn

    (

        fvm::ddt(T)

      + fvm::div(phi, T)

      - fvm::laplacian(alphaEff, T)

     ==

       - fvm::Sp(h*Surface/(rho*Cp*Volume),T)+fvc::Sp(h*Surface /(rho*Cp*Volume),Tw)

    );

with rho and Cp two scalars and Volume = mesh.V() and Surface = mesh.magSf().

My main problem is that the Sp() function allows as arguments a scalar and a volScalarField or volVectorField, and I cannot find a way to fit the surface and volume part into any of these types.

I tried to use a fvc::reconstructMag(mesh.magSf()) to transform the type of mesh.magSf() from a surfaceScalarField into a volScalarField, and also to create a volumeScalarField Volume in the createFields.H with Volume.ref() = mesh.V(), but to no avail.

Does anyone have an idea to get past this problem ?

Thanks in advance,

Matthieu