Dear Mathis and Birger,
Thank you for your answers. I think that the term massOrMolarDensity in
https://git.iws.uni-stuttgart.de/dumux-repositories/dumux/-/blob/master/dumux/flux/box/dispersionflux.hh?ref_type=heads#L103
<https://git.iws.uni-stuttgart.de/dumux-repositories/dumux/-/blob/master/dumux/flux/box/dispersionflux.hh?ref_type=heads#L103>
does not depend on the usage of mol or mass fractions as in the
advective flux it depends on |referenceSystem|which is initially initialized to massavreage immediately in this case
massOrMolardensity=massdensity. On the other hand, I agree with Mathis
unless I don't understand a few things.
Best regards,
Mustapha
Le 15/11/2024 à 10:20, Kelm, Mathis a écrit :
Dear Mustapha and Birger,
the dispersionFlux comes from
fluxVars.compositionalDispersionFlux(phaseIdx)
in
https://git.iws.uni-stuttgart.de/dumux-repositories/dumux/-/blob/master/dumux/porousmediumflow/fluxvariables.hh?ref_type=heads#L120
<https://git.iws.uni-stuttgart.de/dumux-repositories/dumux/-/blob/master/dumux/porousmediumflow/fluxvariables.hh?ref_type=heads#L120>,
which further redirects to the discretization-specific implementation
in e.g.
https://git.iws.uni-stuttgart.de/dumux-repositories/dumux/-/blob/master/dumux/flux/box/dispersionflux.hh?ref_type=heads#L103
<https://git.iws.uni-stuttgart.de/dumux-repositories/dumux/-/blob/master/dumux/flux/box/dispersionflux.hh?ref_type=heads#L103>
where `massOrMolarDensity` is used.
Just like the advective term, where we upwind `massOrMoleDensity *
mobility`, the usage of mass or mole fractions in the equation should
be accounted for. It's only the diffusive fluxes, calculated directly
in the local residual that have the adjustment visible.
The term looks correct to me, do you see any other issues with it?
Best regards,
Mathis
------------------------------------------------------------------------
*From:* DuMux <[email protected]> on behalf of
Birger Hagemann <[email protected]>
*Sent:* Friday, 15 November 2024 09:39:58
*To:* DuMux User Mailing List
*Subject:* Re: [DuMux] dispersion flux in the 1PNC model
(localresidual.hh)
Dear Mustapha,
As far as I understand, you are right.
The current implementation is only correct, when you work with moles
(useMoles = true) and your reference system for the dispersive fluxes
is molarAveraged or when for both mass is used. For other combinations
either the division or multiplication by the molar mass is missing.
This could be implemented in the same way as for the diffusive fluxes.
Regards Birger
*Von:*DuMux <[email protected]> *Im Auftrag von
*mustapha El Ossmani
*Gesendet:* Dienstag, 5. November 2024 23:13
*An:* DuMux User Mailing List <[email protected]>
*Betreff:* [DuMux] dispersion flux in the 1PNC model (localresidual.hh)
Hello DuMuX developers,
I have a question about the implementation of dispersion in the 1PNC
model (*localresidual.hh*). I am asking if the division on the molar
mass is not missing in the case where we choose to work with the molar
fraction and especially that the variable referenceSystemFormulation
is ReferenceSystemFormulation::massAveraged by default.
Below in red the relevant part in the code.
// in case one balance is substituted by the total mole balance
if (useTotalMoleOrMassBalance)
{
// the physical quantities for which we perform upwinding
const auto upwindTerm = [&massOrMoleDensity, phaseIdx]
(const auto& volVars)
{ return massOrMoleDensity(volVars,
phaseIdx)*volVars.mobility(phaseIdx); };
flux[replaceCompEqIdx] +=
fluxVars.advectiveFlux(phaseIdx, upwindTerm);
for(int compIdx = 0; compIdx < numComponents; ++compIdx)
{
//check for the reference system and adapt units
of the diffusive flux accordingly.
if (referenceSystemFormulation ==
ReferenceSystemFormulation::massAveraged)
flux[replaceCompEqIdx] += useMoles ?
diffusiveFluxes[compIdx]/FluidSystem::molarMass(compIdx) :
diffusiveFluxes[compIdx];
else if (referenceSystemFormulation ==
ReferenceSystemFormulation::molarAveraged)
flux[replaceCompEqIdx] += useMoles ?
diffusiveFluxes[compIdx]
:
diffusiveFluxes[compIdx]*FluidSystem::molarMass(compIdx);
else
DUNE_THROW(Dune::NotImplemented, "other
reference systems than mass and molar averaged are not implemented");
}
}
//! Add advective phase energy fluxes. For isothermal
model the contribution is zero.
EnergyLocalResidual::heatConvectionFlux(flux, fluxVars,
phaseIdx);
if constexpr (ModelTraits::enableCompositionalDispersion())
{
if constexpr
(FVElementGeometry::GridGeometry::discMethod ==
DiscretizationMethods::box && numPhases == 1)
{
const auto dispersionFluxes =
fluxVars.compositionalDispersionFlux(phaseIdx);
for (int compIdx = 0; compIdx < numComponents;
++compIdx)
{
****flux[compIdx] += dispersionFluxes[compIdx]; **
}
}
else
DUNE_THROW(Dune::NotImplemented, "Dispersion
Fluxes are only implemented for single phase flows using the Box
method.");
}
}
Thanks in advance
Regards
Mustapha
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