[pm-ff] Use 1padapter instead of phase index

exercises/exercise-coupling-ff-pm/models/ex_models_ffproblem.hh

@@ -26,6 +26,7 @@
 
 #include <dune/grid/yaspgrid.hh>
 
+#include <dumux/material/fluidsystems/1padapter.hh>
 #include <dumux/material/fluidsystems/h2oair.hh>
 
 #include <dumux/freeflow/navierstokes/problem.hh>
@@ -44,11 +45,12 @@ NEW_TYPE_TAG(StokesTypeTag, INHERITS_FROM(StaggeredFreeFlowModel, NavierStokesNC
 // Set the grid type
 SET_TYPE_PROP(StokesTypeTag, Grid, Dune::YaspGrid<2, Dune::EquidistantOffsetCoordinates<typename GET_PROP_TYPE(TypeTag, Scalar), 2> >);
 
-// Set the fluid system
-SET_TYPE_PROP(StokesTypeTag, FluidSystem, FluidSystems::H2OAir<typename GET_PROP_TYPE(TypeTag, Scalar)>);
-
-// Set phase index (gas)
-SET_INT_PROP(StokesTypeTag, PhaseIdx, GET_PROP_TYPE(TypeTag, FluidSystem)::gasPhaseIdx);
+// The fluid system
+SET_PROP(StokesTypeTag, FluidSystem)
+{
+    using H2OAir = FluidSystems::H2OAir<typename GET_PROP_TYPE(TypeTag, Scalar)>;
+    using type = FluidSystems::OnePAdapter<H2OAir, H2OAir::gasPhaseIdx>;
+};
 
 // Do not replace one equation with a total mass balance
 SET_INT_PROP(StokesTypeTag, ReplaceCompEqIdx, 3);
@@ -101,10 +103,6 @@ class StokesSubProblem : public NavierStokesProblem<TypeTag>
 
     static constexpr bool useMoles = GET_PROP_TYPE(TypeTag, ModelTraits)::useMoles();
 
-    static constexpr auto dim = GET_PROP_TYPE(TypeTag, ModelTraits)::dim();
-    static constexpr auto phaseIdx = GET_PROP_VALUE(TypeTag, PhaseIdx);
-    static constexpr auto transportCompIdx = 1 - phaseIdx;
-
 public:
     StokesSubProblem(std::shared_ptr<const FVGridGeometry> fvGridGeometry, std::shared_ptr<CouplingManager> couplingManager)
     : ParentType(fvGridGeometry, "Stokes"), eps_(1e-6), couplingManager_(couplingManager)
@@ -159,27 +157,27 @@ public:
 
         if(onLeftBoundary_(globalPos))
         {
-            values.setDirichlet(transportCompIdx + dim);
+            values.setDirichlet(Indices::conti0EqIdx + 1);
             values.setDirichlet(Indices::velocityXIdx);
             values.setDirichlet(Indices::velocityYIdx);
         }
         else if(onRightBoundary_(globalPos))
         {
             values.setDirichlet(Indices::pressureIdx);
-            values.setOutflow(transportCompIdx + dim);
+            values.setOutflow(Indices::conti0EqIdx + 1);
         }
         else
         {
             values.setDirichlet(Indices::velocityXIdx);
             values.setDirichlet(Indices::velocityYIdx);
-            values.setNeumann(phaseIdx + dim);
-            values.setNeumann(transportCompIdx + dim);
+            values.setNeumann(Indices::conti0EqIdx);
+            values.setNeumann(Indices::conti0EqIdx + 1);
         }
 
         if (couplingManager().isCoupledEntity(CouplingManager::stokesIdx, scvf))
         {
-            values.setCouplingNeumann(phaseIdx + dim);
-            values.setCouplingNeumann(transportCompIdx + dim);
+            values.setCouplingNeumann(Indices::conti0EqIdx);
+            values.setCouplingNeumann(Indices::conti0EqIdx + 1);
             values.setCouplingNeumann(Indices::momentumYBalanceIdx);
             values.setBJS(Indices::momentumXBalanceIdx);
         }
@@ -257,11 +255,11 @@ public:
     {
         FluidState fluidState;
         updateFluidStateForBC_(fluidState, pressure_);
-        const Scalar density = FluidSystem::density(fluidState, phaseIdx);
+        const Scalar density = FluidSystem::density(fluidState, 0);
 
         PrimaryVariables values(0.0);
         values[Indices::pressureIdx] = pressure_ + density*this->gravity()[1]*(globalPos[1] - this->fvGridGeometry().bBoxMin()[1]);
-        values[transportCompIdx + dim] = moleFraction_;
+        values[Indices::conti0EqIdx + 1] = moleFraction_;
         values[Indices::velocityXIdx] = 4.0 * velocity_ * (globalPos[1] - this->fvGridGeometry().bBoxMin()[1])
                                                         * (this->fvGridGeometry().bBoxMax()[1] - globalPos[1])
                                                         / (height_() * height_());
@@ -307,22 +305,22 @@ private:
     void updateFluidStateForBC_(FluidState& fluidState, const Scalar pressure) const
     {
         fluidState.setTemperature(temperature());
-        fluidState.setPressure(phaseIdx, pressure);
-        fluidState.setSaturation(phaseIdx, 1.0);
-        fluidState.setMoleFraction(phaseIdx, transportCompIdx, moleFraction_);
-        fluidState.setMoleFraction(phaseIdx, phaseIdx, 1.0 - moleFraction_);
+        fluidState.setPressure(0, pressure);
+        fluidState.setSaturation(0, 1.0);
+        fluidState.setMoleFraction(0, 1, moleFraction_);
+        fluidState.setMoleFraction(0, 0, 1.0 - moleFraction_);
 
         typename FluidSystem::ParameterCache paramCache;
-        paramCache.updatePhase(fluidState, phaseIdx);
+        paramCache.updatePhase(fluidState, 0);
 
-        const Scalar density = FluidSystem::density(fluidState, paramCache, phaseIdx);
-        fluidState.setDensity(phaseIdx, density);
+        const Scalar density = FluidSystem::density(fluidState, paramCache, 0);
+        fluidState.setDensity(0, density);
 
-        const Scalar molarDensity = FluidSystem::molarDensity(fluidState, paramCache, phaseIdx);
-        fluidState.setMolarDensity(phaseIdx, molarDensity);
+        const Scalar molarDensity = FluidSystem::molarDensity(fluidState, paramCache, 0);
+        fluidState.setMolarDensity(0, molarDensity);
 
-        const Scalar enthalpy = FluidSystem::enthalpy(fluidState, paramCache, phaseIdx);
-        fluidState.setEnthalpy(phaseIdx, enthalpy);
+        const Scalar enthalpy = FluidSystem::enthalpy(fluidState, paramCache, 0);
+        fluidState.setEnthalpy(0, enthalpy);
     }
     // the height of the free-flow domain
     const Scalar height_() const

exercises/exercise-coupling-ff-pm/models/ex_models_pmproblem.hh

@@ -28,6 +28,7 @@
 
 #include <dumux/discretization/cellcentered/tpfa/properties.hh>
 #include <dumux/io/gnuplotinterface.hh>
+#include <dumux/material/fluidsystems/1padapter.hh>
 #include <dumux/material/fluidsystems/h2oair.hh>
 #include <dumux/material/fluidmatrixinteractions/diffusivityconstanttortuosity.hh>
 
@@ -49,10 +50,11 @@ NEW_TYPE_TAG(DarcyTypeTag, INHERITS_FROM(CCTpfaModel, OnePNC));
 SET_TYPE_PROP(DarcyTypeTag, Problem, Dumux::DarcySubProblem<TypeTag>);
 
 // The fluid system
-SET_TYPE_PROP(DarcyTypeTag, FluidSystem, FluidSystems::H2OAir<typename GET_PROP_TYPE(TypeTag, Scalar)>);
-
-// Use gas as phase
-SET_INT_PROP(DarcyTypeTag, PhaseIdx, GET_PROP_TYPE(TypeTag, FluidSystem)::gasPhaseIdx);
+SET_PROP(DarcyTypeTag, FluidSystem)
+{
+    using H2OAir = FluidSystems::H2OAir<typename GET_PROP_TYPE(TypeTag, Scalar)>;
+    using type = FluidSystems::OnePAdapter<H2OAir, H2OAir::gasPhaseIdx>;
+};
 
 // Use moles
 SET_BOOL_PROP(DarcyTypeTag, UseMoles, true);
@@ -96,8 +98,8 @@ class DarcySubProblem : public PorousMediumFlowProblem<TypeTag>
         // primary variable indices
         conti0EqIdx = Indices::conti0EqIdx,
         pressureIdx = Indices::pressureIdx,
-        phaseIdx = Indices::fluidSystemPhaseIdx,
-        transportCompIdx = 1-phaseIdx
+        phaseIdx = 0,
+        transportCompIdx = 1
     };
 
     using Element = typename GridView::template Codim<0>::Entity;
@@ -181,11 +183,8 @@ public:
             for (auto&& scv : scvs(fvGeometry))
             {
                 const auto& volVars = elemVolVars[scv];
-                for(int phaseIdx = 0; phaseIdx < FluidSystem::numPhases; ++phaseIdx)
-                {
-                    // insert calculation of the water mass here
-                    waterMass += 0.0;
-                }
+                // insert calculation of the water mass here
+                waterMass += 0.0;
             }
         }
 

exercises/exercise-coupling-ff-pm/turbulence/ex_turbulence_ffproblem.hh

@@ -25,6 +25,7 @@
 
 #include <dune/grid/yaspgrid.hh>
 
+#include <dumux/material/fluidsystems/1padapter.hh>
 #include <dumux/material/fluidsystems/h2oair.hh>
 #include <dumux/discretization/staggered/freeflow/properties.hh>
 
@@ -43,11 +44,13 @@ NEW_TYPE_TAG(ZeroEqTypeTag, INHERITS_FROM(StaggeredFreeFlowModel, NavierStokesNC
 // Set the grid type
 SET_TYPE_PROP(ZeroEqTypeTag, Grid, Dune::YaspGrid<2, Dune::TensorProductCoordinates<typename GET_PROP_TYPE(TypeTag, Scalar), 2> >);
 
-// set the fluid system
-SET_TYPE_PROP(ZeroEqTypeTag, FluidSystem, FluidSystems::H2OAir<typename GET_PROP_TYPE(TypeTag, Scalar)>);
-
-// set phase index (air)
-SET_INT_PROP(ZeroEqTypeTag, PhaseIdx, GET_PROP_TYPE(TypeTag, FluidSystem)::gasPhaseIdx);
+// The fluid system
+SET_PROP(ZeroEqTypeTag, FluidSystem)
+{
+  using H2OAir = FluidSystems::H2OAir<typename GET_PROP_TYPE(TypeTag, Scalar)>;
+  static constexpr auto phaseIdx = H2OAir::gasPhaseIdx; // simulate the air phase
+  using type = FluidSystems::OnePAdapter<H2OAir, phaseIdx>;
+};
 
 SET_INT_PROP(ZeroEqTypeTag, ReplaceCompEqIdx, 3);
 
@@ -98,9 +101,6 @@ class FreeFlowSubProblem : public NavierStokesProblem<TypeTag>
 
     static constexpr bool useMoles = GET_PROP_TYPE(TypeTag, ModelTraits)::useMoles();
 
-    static constexpr auto phaseIdx = GET_PROP_VALUE(TypeTag, PhaseIdx);
-    static constexpr auto transportCompIdx = 1 - phaseIdx;
-
 public:
     FreeFlowSubProblem(std::shared_ptr<const FVGridGeometry> fvGridGeometry, std::shared_ptr<CouplingManager> couplingManager)
     : ParentType(fvGridGeometry, "Stokes"), eps_(1e-6), couplingManager_(couplingManager)
@@ -157,7 +157,7 @@ public:
         {
             values.setDirichlet(Indices::velocityXIdx);
             values.setDirichlet(Indices::velocityYIdx);
-            values.setDirichlet(Indices::conti0EqIdx);
+            values.setDirichlet(Indices::conti0EqIdx + 1);
             values.setDirichlet(Indices::energyBalanceIdx);
         }
 
@@ -182,7 +182,7 @@ public:
         if (onRightBoundary_(globalPos))
         {
             values.setDirichlet(Indices::pressureIdx);
-            values.setOutflow(Indices::conti0EqIdx);
+            values.setOutflow(Indices::conti0EqIdx + 1);
             values.setOutflow(Indices::energyBalanceIdx);
         }
 
@@ -268,11 +268,11 @@ public:
         FluidState fluidState;
         updateFluidStateForBC_(fluidState, refTemperature(), refPressure(), refMoleFrac());
 
-        const Scalar density = FluidSystem::density(fluidState, phaseIdx);
+        const Scalar density = FluidSystem::density(fluidState, 0);
 
         PrimaryVariables values(0.0);
         values[Indices::pressureIdx] = refPressure() + density*this->gravity()[1]*(globalPos[1] - this->fvGridGeometry().bBoxMin()[1]);
-        values[Indices::conti0EqIdx] = refMoleFrac();
+        values[Indices::conti0EqIdx + 1] = refMoleFrac();
         values[Indices::velocityXIdx] = refVelocity();
         values[Indices::temperatureIdx] = refTemperature();
 
@@ -338,22 +338,22 @@ private:
                                 const Scalar pressure, const Scalar moleFraction) const
     {
         fluidState.setTemperature(temperature);
-        fluidState.setPressure(phaseIdx, pressure);
-        fluidState.setSaturation(phaseIdx, 1.0);
-        fluidState.setMoleFraction(phaseIdx, transportCompIdx, moleFraction);
-        fluidState.setMoleFraction(phaseIdx, phaseIdx, 1.0 - moleFraction);
+        fluidState.setPressure(0, pressure);
+        fluidState.setSaturation(0, 1.0);
+        fluidState.setMoleFraction(0, 1, moleFraction);
+        fluidState.setMoleFraction(0, 0, 1.0 - moleFraction);
 
         typename FluidSystem::ParameterCache paramCache;
-        paramCache.updatePhase(fluidState, phaseIdx);
+        paramCache.updatePhase(fluidState, 0);
 
-        const Scalar density = FluidSystem::density(fluidState, paramCache, phaseIdx);
-        fluidState.setDensity(phaseIdx, density);
+        const Scalar density = FluidSystem::density(fluidState, paramCache, 0);
+        fluidState.setDensity(0, density);
 
-        const Scalar molarDensity = FluidSystem::molarDensity(fluidState, paramCache, phaseIdx);
-        fluidState.setMolarDensity(phaseIdx, molarDensity);
+        const Scalar molarDensity = FluidSystem::molarDensity(fluidState, paramCache, 0);
+        fluidState.setMolarDensity(0, molarDensity);
 
-        const Scalar enthalpy = FluidSystem::enthalpy(fluidState, paramCache, phaseIdx);
-        fluidState.setEnthalpy(phaseIdx, enthalpy);
+        const Scalar enthalpy = FluidSystem::enthalpy(fluidState, paramCache, 0);
+        fluidState.setEnthalpy(0, enthalpy);
     }
 
     // the height of the free-flow domain

exercises/solution/exercise-coupling-ff-pm/models/ex_models_ffproblem.hh

@@ -26,6 +26,7 @@
 
 #include <dune/grid/yaspgrid.hh>
 
+#include <dumux/material/fluidsystems/1padapter.hh>
 #include <dumux/material/fluidsystems/h2oair.hh>
 
 #include <dumux/freeflow/navierstokes/problem.hh>
@@ -44,11 +45,12 @@ NEW_TYPE_TAG(StokesTypeTag, INHERITS_FROM(StaggeredFreeFlowModel, NavierStokesNC
 // Set the grid type
 SET_TYPE_PROP(StokesTypeTag, Grid, Dune::YaspGrid<2, Dune::EquidistantOffsetCoordinates<typename GET_PROP_TYPE(TypeTag, Scalar), 2> >);
 
-// Set the fluid system
-SET_TYPE_PROP(StokesTypeTag, FluidSystem, FluidSystems::H2OAir<typename GET_PROP_TYPE(TypeTag, Scalar)>);
-
-// Set phase index (gas)
-SET_INT_PROP(StokesTypeTag, PhaseIdx, GET_PROP_TYPE(TypeTag, FluidSystem)::gasPhaseIdx);
+// The fluid system
+SET_PROP(StokesTypeTag, FluidSystem)
+{
+    using H2OAir = FluidSystems::H2OAir<typename GET_PROP_TYPE(TypeTag, Scalar)>;
+    using type = FluidSystems::OnePAdapter<H2OAir, H2OAir::gasPhaseIdx>;
+};
 
 // Do not replace one equation with a total mass balance
 SET_INT_PROP(StokesTypeTag, ReplaceCompEqIdx, 3);
@@ -102,8 +104,7 @@ class StokesSubProblem : public NavierStokesProblem<TypeTag>
     static constexpr bool useMoles = GET_PROP_TYPE(TypeTag, ModelTraits)::useMoles();
 
     static constexpr auto dim = GET_PROP_TYPE(TypeTag, ModelTraits)::dim();
-    static constexpr auto phaseIdx = GET_PROP_VALUE(TypeTag, PhaseIdx);
-    static constexpr auto transportCompIdx = 1 - phaseIdx;
+    static constexpr auto transportCompIdx = 1;
 
 public:
     StokesSubProblem(std::shared_ptr<const FVGridGeometry> fvGridGeometry, std::shared_ptr<CouplingManager> couplingManager)
@@ -159,27 +160,27 @@ public:
 
         if(onLeftBoundary_(globalPos))
         {
-            values.setDirichlet(transportCompIdx + dim);
+            values.setDirichlet(Indices::conti0EqIdx + 1);
             values.setDirichlet(Indices::velocityXIdx);
             values.setDirichlet(Indices::velocityYIdx);
         }
         else if(onRightBoundary_(globalPos))
         {
             values.setDirichlet(Indices::pressureIdx);
-            values.setOutflow(transportCompIdx + dim);
+            values.setOutflow(Indices::conti0EqIdx + 1);
         }
         else
         {
             values.setDirichlet(Indices::velocityXIdx);
             values.setDirichlet(Indices::velocityYIdx);
-            values.setNeumann(phaseIdx + dim);
-            values.setNeumann(transportCompIdx + dim);
+            values.setNeumann(Indices::conti0EqIdx);
+            values.setNeumann(Indices::conti0EqIdx + 1);
         }
 
         if (couplingManager().isCoupledEntity(CouplingManager::stokesIdx, scvf))
         {
-            values.setCouplingNeumann(phaseIdx + dim);
-            values.setCouplingNeumann(transportCompIdx + dim);
+            values.setCouplingNeumann(Indices::conti0EqIdx);
+            values.setCouplingNeumann(Indices::conti0EqIdx + 1);
             values.setCouplingNeumann(Indices::momentumYBalanceIdx);
             values.setBJS(Indices::momentumXBalanceIdx);
         }
@@ -257,11 +258,11 @@ public:
     {
         FluidState fluidState;
         updateFluidStateForBC_(fluidState, pressure_);
-        const Scalar density = FluidSystem::density(fluidState, phaseIdx);
+        const Scalar density = FluidSystem::density(fluidState, 0);
 
         PrimaryVariables values(0.0);
         values[Indices::pressureIdx] = pressure_ + density*this->gravity()[1]*(globalPos[1] - this->fvGridGeometry().bBoxMin()[1]);
-        values[transportCompIdx + dim] = moleFraction_;
+        values[Indices::conti0EqIdx + 1] = moleFraction_;
         values[Indices::velocityXIdx] = 4.0 * velocity_ * (globalPos[1] - this->fvGridGeometry().bBoxMin()[1])
                                                         * (this->fvGridGeometry().bBoxMax()[1] - globalPos[1])
                                                         / (height_() * height_());
@@ -307,22 +308,22 @@ private:
     void updateFluidStateForBC_(FluidState& fluidState, const Scalar pressure) const
     {
         fluidState.setTemperature(temperature());
-        fluidState.setPressure(phaseIdx, pressure);
-        fluidState.setSaturation(phaseIdx, 1.0);
-        fluidState.setMoleFraction(phaseIdx, transportCompIdx, moleFraction_);
-        fluidState.setMoleFraction(phaseIdx, phaseIdx, 1.0 - moleFraction_);
+        fluidState.setPressure(0, pressure);
+        fluidState.setSaturation(0, 1.0);
+        fluidState.setMoleFraction(0, 1, moleFraction_);
+        fluidState.setMoleFraction(0, 0, 1.0 - moleFraction_);
 
         typename FluidSystem::ParameterCache paramCache;
-        paramCache.updatePhase(fluidState, phaseIdx);
+        paramCache.updatePhase(fluidState, 0);
 
-        const Scalar density = FluidSystem::density(fluidState, paramCache, phaseIdx);
-        fluidState.setDensity(phaseIdx, density);
+        const Scalar density = FluidSystem::density(fluidState, paramCache, 0);
+        fluidState.setDensity(0, density);
 
-        const Scalar molarDensity = FluidSystem::molarDensity(fluidState, paramCache, phaseIdx);
-        fluidState.setMolarDensity(phaseIdx, molarDensity);
+        const Scalar molarDensity = FluidSystem::molarDensity(fluidState, paramCache, 0);
+        fluidState.setMolarDensity(0, molarDensity);
 
-        const Scalar enthalpy = FluidSystem::enthalpy(fluidState, paramCache, phaseIdx);
-        fluidState.setEnthalpy(phaseIdx, enthalpy);
+        const Scalar enthalpy = FluidSystem::enthalpy(fluidState, paramCache, 0);
+        fluidState.setEnthalpy(0, enthalpy);
     }
     // the height of the free-flow domain
     const Scalar height_() const

exercises/solution/exercise-coupling-ff-pm/models/ex_models_pmproblem.hh

@@ -26,6 +26,7 @@
 
 #include <dune/grid/yaspgrid.hh>
 
+#include <dumux/material/fluidsystems/1padapter.hh>
 #include <dumux/discretization/cellcentered/tpfa/properties.hh>
 #include <dumux/io/gnuplotinterface.hh>
 #include <dumux/material/fluidsystems/h2oair.hh>
@@ -58,12 +59,15 @@ NEW_TYPE_TAG(DarcyTypeTag, INHERITS_FROM(CCTpfaModel, OnePNC));
 SET_TYPE_PROP(DarcyTypeTag, Problem, Dumux::DarcySubProblem<TypeTag>);
 
 // The fluid system
-SET_TYPE_PROP(DarcyTypeTag, FluidSystem, FluidSystems::H2OAir<typename GET_PROP_TYPE(TypeTag, Scalar)>);
-
-// Use gas as phase
+SET_PROP(DarcyTypeTag, FluidSystem)
+{
+    using H2OAir = FluidSystems::H2OAir<typename GET_PROP_TYPE(TypeTag, Scalar)>;
 #if EXNUMBER == 0
-SET_INT_PROP(DarcyTypeTag, PhaseIdx, GET_PROP_TYPE(TypeTag, FluidSystem)::gasPhaseIdx);
+    using type = FluidSystems::OnePAdapter<H2OAir, H2OAir::gasPhaseIdx>;
+#else
+    using type = H2OAir;
 #endif
+};
 
 // Use moles
 SET_BOOL_PROP(DarcyTypeTag, UseMoles, true);
@@ -123,8 +127,8 @@ class DarcySubProblem : public PorousMediumFlowProblem<TypeTag>
 #elif EXNUMBER >= 1
         transportCompIdx = Indices::switchIdx
 #else
-        phaseIdx = Indices::fluidSystemPhaseIdx,
-        transportCompIdx = 1-phaseIdx
+        phaseIdx = 0,
+        transportCompIdx = 1
 #endif
     };
 

exercises/solution/exercise-coupling-ff-pm/turbulence/ex_turbulence_ffproblem.hh

@@ -25,6 +25,7 @@
 
 #include <dune/grid/yaspgrid.hh>
 
+#include <dumux/material/fluidsystems/1padapter.hh>
 #include <dumux/material/fluidsystems/h2oair.hh>
 #include <dumux/discretization/staggered/freeflow/properties.hh>
 
@@ -52,11 +53,13 @@ NEW_TYPE_TAG(ZeroEqTypeTag, INHERITS_FROM(StaggeredFreeFlowModel, NavierStokesNC
 // Set the grid type
 SET_TYPE_PROP(ZeroEqTypeTag, Grid, Dune::YaspGrid<2, Dune::TensorProductCoordinates<typename GET_PROP_TYPE(TypeTag, Scalar), 2> >);
 
-// set the fluid system
-SET_TYPE_PROP(ZeroEqTypeTag, FluidSystem, FluidSystems::H2OAir<typename GET_PROP_TYPE(TypeTag, Scalar)>);
-
-// set phase index (air)
-SET_INT_PROP(ZeroEqTypeTag, PhaseIdx, GET_PROP_TYPE(TypeTag, FluidSystem)::gasPhaseIdx);
+// The fluid system
+SET_PROP(ZeroEqTypeTag, FluidSystem)
+{
+  using H2OAir = FluidSystems::H2OAir<typename GET_PROP_TYPE(TypeTag, Scalar)>;
+  static constexpr auto phaseIdx = H2OAir::gasPhaseIdx; // simulate the air phase
+  using type = FluidSystems::OnePAdapter<H2OAir, phaseIdx>;
+};
 
 SET_INT_PROP(ZeroEqTypeTag, ReplaceCompEqIdx, 3);
 
@@ -113,9 +116,6 @@ class FreeFlowSubProblem : public NavierStokesProblem<TypeTag>
 
     static constexpr bool useMoles = GET_PROP_TYPE(TypeTag, ModelTraits)::useMoles();
 
-    static constexpr auto phaseIdx = GET_PROP_VALUE(TypeTag, PhaseIdx);
-    static constexpr auto transportCompIdx = 1 - phaseIdx;
-
 public:
     FreeFlowSubProblem(std::shared_ptr<const FVGridGeometry> fvGridGeometry, std::shared_ptr<CouplingManager> couplingManager)
     : ParentType(fvGridGeometry, "Stokes"), eps_(1e-6), couplingManager_(couplingManager)
@@ -172,7 +172,7 @@ public:
         {
             values.setDirichlet(Indices::velocityXIdx);
             values.setDirichlet(Indices::velocityYIdx);
-            values.setDirichlet(Indices::conti0EqIdx);
+            values.setDirichlet(Indices::conti0EqIdx + 1);
             values.setDirichlet(Indices::energyBalanceIdx);
         }
 
@@ -201,7 +201,7 @@ public:
         if (onRightBoundary_(globalPos))
         {
             values.setDirichlet(Indices::pressureIdx);
-            values.setOutflow(Indices::conti0EqIdx);
+            values.setOutflow(Indices::conti0EqIdx + 1);
             values.setOutflow(Indices::energyBalanceIdx);
         }
 
@@ -299,11 +299,11 @@ public:
         FluidState fluidState;
         updateFluidStateForBC_(fluidState, refTemperature(), refPressure(), refMoleFrac());
 
-        const Scalar density = FluidSystem::density(fluidState, phaseIdx);
+        const Scalar density = FluidSystem::density(fluidState, 0);
 
         PrimaryVariables values(0.0);
         values[Indices::pressureIdx] = refPressure() + density*this->gravity()[1]*(globalPos[1] - this->fvGridGeometry().bBoxMin()[1]);
-        values[Indices::conti0EqIdx] = refMoleFrac();
+        values[Indices::conti0EqIdx + 1] = refMoleFrac();
         values[Indices::velocityXIdx] = refVelocity();
         values[Indices::temperatureIdx] = refTemperature();
 
@@ -369,22 +369,22 @@ private:
                                 const Scalar pressure, const Scalar moleFraction) const
     {
         fluidState.setTemperature(temperature);
-        fluidState.setPressure(phaseIdx, pressure);
-        fluidState.setSaturation(phaseIdx, 1.0);
-        fluidState.setMoleFraction(phaseIdx, transportCompIdx, moleFraction);
-        fluidState.setMoleFraction(phaseIdx, phaseIdx, 1.0 - moleFraction);
+        fluidState.setPressure(0, pressure);
+        fluidState.setSaturation(0, 1.0);
+        fluidState.setMoleFraction(0, 1, moleFraction);
+        fluidState.setMoleFraction(0, 0, 1.0 - moleFraction);
 
         typename FluidSystem::ParameterCache paramCache;
-        paramCache.updatePhase(fluidState, phaseIdx);
+        paramCache.updatePhase(fluidState, 0);
 
-        const Scalar density = FluidSystem::density(fluidState, paramCache, phaseIdx);
-        fluidState.setDensity(phaseIdx, density);
+        const Scalar density = FluidSystem::density(fluidState, paramCache, 0);
+        fluidState.setDensity(0, density);
 
-        const Scalar molarDensity = FluidSystem::molarDensity(fluidState, paramCache, phaseIdx);
-        fluidState.setMolarDensity(phaseIdx, molarDensity);
+        const Scalar molarDensity = FluidSystem::molarDensity(fluidState, paramCache, 0);
+        fluidState.setMolarDensity(0, molarDensity);
 
-        const Scalar enthalpy = FluidSystem::enthalpy(fluidState, paramCache, phaseIdx);
-        fluidState.setEnthalpy(phaseIdx, enthalpy);
+        const Scalar enthalpy = FluidSystem::enthalpy(fluidState, paramCache, 0);
+        fluidState.setEnthalpy(0, enthalpy);
     }
 
     // the height of the free-flow domain