[rhythm]

Hi folks,

I have been looking at bounding constraint implementation in combustion solvers. As known the species scalarFields for these solvers are supposed to be bounded to range [0:1]. The lower bound implementation is clear as it is only needed to clean up numerical error build up, whereas the upper bound is slightly more involved and raises some questions.

As far as I can tell there is only one part in the code that takes care of upper species bound. It can be seen in multiComponentMixture class. There is a member function called correctMassFractions(), which in summary does the following:

template<class ThermoType>
void Foam::multiComponentMixture<ThermoType>::correctMassFractions()
{
    volScalarField Yt("Yt", 1.0*Y_[0]);

    for (label n=1; n<Y_.size(); n++)
    {
        Yt += Y_[n];
    }
<...>
    forAll(Y_, n)
    {
        Y_[n] /= Yt;
    }
}

This member function is invoked during construction of multiComponentMixture object. Which leads me to my questions:

1) As it can be seen the normalisation constraint is only applied to the internalField values of Y_. This does not prevent silly users (like me ) from specifying boundary condition values higher than 1. Wouldn't it make sense to include some sort of fail safe check to prevent users from specifying unphysical values at the boundaries?

2) correctMassFractions() function, as far as I can tell, is only called during construction of multiComponentMixture, which probably makes sense as we wouldn't want to additionally fiddle with the field values at runtime apart from what the solver calculates. Nonetheless, I would expect some sort of procedure telling the code that there is an upper constraint for field values. Unfortunately, I can't seem to find any of that in the code. Does anyone know if I am missing something or are the field values kept in range [0:1] by a correct choice of reaction, thermo parameters?

Cheers,
Ben