59        constexpr int numFluidPhases = VolumeVariables::numFluidPhases();
 
   62        Scalar lambdaFluid = 0.0;
 
   63        for (
int phaseIdx = 0; phaseIdx < numFluidPhases; ++phaseIdx)
 
   64            lambdaFluid += volVars.fluidThermalConductivity(phaseIdx)*volVars.saturation(phaseIdx);
 
   66        const Scalar lambdaSolid = volVars.solidThermalConductivity();
 
   67        const Scalar porosity = volVars.porosity();
 
   69        return lambdaSolid*(1-porosity) + lambdaFluid*porosity;