38    static auto flux(
const Problem& problem,
 
   39                     const Element& element,
 
   40                     const FVElementGeometry& fvGeometry,
 
   41                     const ElementVolumeVariables& elemVolVars,
 
   42                     const typename FVElementGeometry::SubControlVolumeFace& scvf,
 
   43                     const ElementFluxVariablesCache& elemFluxVarsCache)
 
   45        const auto& insideScv = fvGeometry.scv(scvf.insideScvIdx());
 
   46        const auto& outsideScv = fvGeometry.scv(scvf.outsideScvIdx());
 
   47        const auto& insideVolVars = elemVolVars[insideScv];
 
   48        const auto& outsideVolVars = elemVolVars[outsideScv];
 
   49        const auto& fluxVarsCache = elemFluxVarsCache[scvf];
 
   51        static constexpr auto numPhases = ElementVolumeVariables::VolumeVariables::numFluidPhases();
 
   52        using Scalar = 
typename ElementVolumeVariables::VolumeVariables::PrimaryVariables::value_type;
 
   55        for (
int phaseIdx = 0; phaseIdx < numPhases; phaseIdx++)
 
   57            auto insideThermalConducitivity = insideVolVars.fluidThermalConductivity(phaseIdx);
 
   58            auto outsideThermalConducitivity = outsideVolVars.fluidThermalConductivity(phaseIdx);
 
   60            auto thermalConductivity = 
Dumux::harmonicMean(insideThermalConducitivity, outsideThermalConducitivity);
 
   61            auto area = fluxVarsCache.throatCrossSectionalArea(phaseIdx);
 
   64            const Scalar deltaT = insideVolVars.temperature() - outsideVolVars.temperature();
 
   65            const Scalar gradT = deltaT/fluxVarsCache.throatLength();
 
   67            heatflux += thermalConductivity*gradT*area;
 
   69            if constexpr (!std::is_same_v<MolecularDiffusionType, Detail::NoDiffusionType>)
 
   70                heatflux += componentEnthalpyFlux_(problem, element, fvGeometry, elemVolVars, scvf, elemFluxVarsCache, phaseIdx);
 
 
   90        const auto diffusiveFlux = MolecularDiffusionType::flux(problem, element, fvGeometry, elemVolVars, scvf, phaseIdx, elemFluxVarsCache);
 
   95            const Scalar componentEnthalpy = FluidSystem::componentEnthalpy(upstreamVolVars.fluidState(), phaseIdx, compIdx);