[WIP] Preconditioning for multicomponent flows

Common/include/CConfig.hpp

@@ -892,6 +892,7 @@ class CConfig {
   Initial_BCThrust,                /*!< \brief Ratio of turbulent to laminar viscosity at the actuator disk. */
   Pressure_FreeStream,             /*!< \brief Total pressure of the fluid. */
   Pressure_Thermodynamic,          /*!< \brief Thermodynamic pressure of the fluid. */
+  Standard_Ref_Temperature,        /*!< \brief Standard reference temperature for multicomponent flows. */
   Temperature_FreeStream,          /*!< \brief Total temperature of the fluid.  */
   Temperature_ve_FreeStream;       /*!< \brief Total vibrational-electronic temperature of the fluid.  */
   unsigned short wallModel_MaxIter; /*!< \brief maximum number of iterations for the Newton method for the wall model */
@@ -1902,6 +1903,12 @@ class CConfig {
    */
   su2double GetPressure_Thermodynamic(void) const { return Pressure_Thermodynamic; }
 
+  /*!
+   * \brief Get the value of the standard reference temperature for multicomponent flows.
+   * \return Standard reference temperature, Non-dimensionalized if it is needed for Non-Dimensional problems.
+   */
+  su2double GetStandard_RefTemperatureND(void) const { return Standard_Ref_Temperature / Temperature_Ref; }
+
   /*!
    * \brief Get the value of the non-dimensionalized thermodynamic pressure.
    * \return Non-dimensionalized thermodynamic pressure.

Common/src/CConfig.cpp

@@ -1217,6 +1217,9 @@ void CConfig::SetConfig_Options() {
   addDoubleOption("GAMMA_VALUE", Gamma, 1.4);
   /*!\brief THERMODYNAMIC_PRESSURE  \n DESCRIPTION: Thermodynamics(operating) Pressure (101325 Pa), only for incompressible flows) \ingroup Config*/
   addDoubleOption("THERMODYNAMIC_PRESSURE", Pressure_Thermodynamic, 101325.0);
+  /*!\brief STANDARD_REFERENCE_TEMPERATURE  \n DESCRIPTION: Standard reference temperature (298.15K), only for
+   * multicomponent incompressible flows) \ingroup Config*/
+  addDoubleOption("STANDARD_REFERENCE_TEMPERATURE", Standard_Ref_Temperature, 298.15);
   /*!\brief CP_VALUE  \n DESCRIPTION: Specific heat at constant pressure, Cp (1004.703 J/kg*K (air), constant density incompressible fluids only) \ingroup Config*/
   addDoubleListOption("SPECIFIC_HEAT_CP", nSpecific_Heat_Cp, Specific_Heat_Cp);
   /*!\brief THERMAL_EXPANSION_COEFF  \n DESCRIPTION: Thermal expansion coefficient (0.00347 K^-1 (air), used for Boussinesq approximation for liquids/non-ideal gases) \ingroup Config*/

SU2_CFD/include/fluid/CFluidModel.hpp

@@ -47,6 +47,7 @@ class CLookUpTable;
 class CFluidModel {
  protected:
   su2double StaticEnergy{0.0};     /*!< \brief Internal Energy. */
+  su2double Enthalpy{0.0};         /*!<*\brief Enthalpy. */
   su2double Entropy{0.0};          /*!< \brief Entropy. */
   su2double Density{0.0};          /*!< \brief Density. */
   su2double Pressure{0.0};         /*!< \brief Pressure. */
@@ -113,6 +114,11 @@ class CFluidModel {
    */
   su2double GetStaticEnergy() const { return StaticEnergy; }
 
+  /*!
+   * \brief Get fluid enthalpy.
+   */
+  su2double GetEnthalpy() const { return Enthalpy; }
+
   /*!
    * \brief Get fluid density.
    */
@@ -186,6 +192,16 @@ class CFluidModel {
     return mass_diffusivity;
   }
 
+  /*!
+   * \brief Get heat diffusivity terms.
+   */
+  virtual void GetEnthalpyDiffusivity(su2double* enthalpy_diffusions = nullptr) {}
+
+  /*!
+   * \brief Get gradient heat diffusivity terms.
+   */
+  virtual void GetGradEnthalpyDiffusivity(su2double* grad_enthalpy_diffusions = nullptr) {}
+
   /*!
    * \brief Get fluid pressure partial derivative.
    */
@@ -339,6 +355,13 @@ class CFluidModel {
    */
   virtual void SetTDState_T(su2double val_Temperature, const su2double* val_scalars = nullptr) {}
 
+  /*!
+   * \brief Virtual member.
+   * \param[in] val_enthalpy - Enthalpy value at the point.
+   */
+  virtual void ComputeTempFromEnthalpy(su2double val_enthalpy, su2double* val_temperature,
+                                       const su2double* val_scalars = nullptr) {}
+
   /*!
    * \brief Set fluid eddy viscosity provided by a turbulence model needed for computing effective thermal conductivity.
    */

SU2_CFD/include/fluid/CFluidScalar.hpp

@@ -42,6 +42,7 @@ class CFluidScalar final : public CFluidModel {
   const int n_species_mixture;            /*!< \brief Number of species in mixture. */
   su2double Gas_Constant;           /*!< \brief Specific gas constant. */
   const su2double Pressure_Thermodynamic; /*!< \brief Constant pressure thermodynamic. */
+  const su2double Ref_Temperature;        /*!< \brief Reference temperature. */
   const su2double GasConstant_Ref;        /*!< \brief Gas constant reference needed for Nondimensional problems. */
   const su2double Prandtl_Number;         /*!< \brief Prandlt number.*/
 
@@ -91,6 +92,11 @@ class CFluidScalar final : public CFluidModel {
    */
   su2double ComputeMeanSpecificHeatCp(const su2double* val_scalars);
 
+  /*!
+   * \brief Compute Enthalpy given the temperature and scalars.
+   */
+  su2double ComputeEnthalpyFromT(const su2double val_temperature, const su2double* val_scalars);
+
   /*!
    * \brief Compute gas constant for mixture.
    */
@@ -137,6 +143,22 @@ class CFluidScalar final : public CFluidModel {
    */
   inline su2double GetMassDiffusivity(int ivar) override { return massDiffusivity[ivar]; }
 
+  /*!
+   * \brief Get enthalpy diffusivity terms.
+   */
+  void GetEnthalpyDiffusivity(su2double* enthalpy_diffusions) override;
+
+  /*!
+   * \brief Get gradient enthalpy diffusivity terms.
+   */
+  void GetGradEnthalpyDiffusivity(su2double* grad_enthalpy_diffusions) override;
+
+  /*!
+   * \brief Compute Temperature from Enthalpy and scalars.
+   */
+  void ComputeTempFromEnthalpy(const su2double val_enthalpy, su2double* val_temperature,
+                               const su2double* val_scalars) override;
+
   /*!
    * \brief Set the Dimensionless State using Temperature.
    * \param[in] t - Temperature value at the point.

SU2_CFD/include/numerics/CNumerics.hpp

@@ -103,6 +103,9 @@ class CNumerics {
   su2double
   Enthalpy_i,  /*!< \brief Enthalpy at point i. */
   Enthalpy_j;  /*!< \brief Enthalpy at point j. */
+  su2double 
+  WorkingVariable_i,  /*!< \brief Working Variable at point i for incompressible solver. */
+  WorkingVariable_j;  /*!< \brief Working Variable at point j for incompressible solver. */
   su2double
   dist_i,  /*!< \brief Distance of point i to the nearest wall. */
   dist_j;  /*!< \brief Distance of point j to the nearest wall. */
@@ -130,6 +133,10 @@ class CNumerics {
   const su2double
   *ScalarVar_i,   /*!< \brief Vector of scalar variables at point i. */
   *ScalarVar_j;   /*!< \brief Vector of scalar variables at point j. */
+  su2double
+  HeatFluxDiffusion;   /*!< \brief Heat flux due to enthalpy diffusion for multicomponent. */
+  su2double
+  Jac_HeatFluxDiffusion;   /*!< \brief Heat flux jacobian due to enthalpy diffusion for multicomponent. */
   const su2double
   *TransVar_i,  /*!< \brief Vector of turbulent variables at point i. */
   *TransVar_j;  /*!< \brief Vector of turbulent variables at point j. */
@@ -188,6 +195,8 @@ class CNumerics {
 
   bool nemo;                      /*!< \brief Flag for NEMO problems  */
 
+  bool energy_multicomponent = false; /*!< \brief Flag for multicomponent and reacting flow  */
+
   bool bounded_scalar = false;    /*!< \brief Flag for bounded scalar problem */
 
 public:
@@ -751,6 +760,20 @@ class CNumerics {
     Diffusion_Coeff_j = val_diffusioncoeff_j;
   }
 
+  /*!
+   * \brief Set the heat flux due to enthalpy diffusion
+   * \param[in] val_heatfluxdiffusion - Value of the heat flux due to enthalpy diffusion.
+   */
+  inline void SetHeatFluxDiffusion(su2double val_heatfluxdiffusion) { HeatFluxDiffusion = val_heatfluxdiffusion; }
+
+  /*!
+   * \brief Set Jacobian of the heat flux due to enthalpy diffusion
+   * \param[in] val_jacheatfluxdiffusion - Value of the heat flux jacobian due to enthalpy diffusion.
+   */
+  inline void SetJacHeatFluxDiffusion(su2double val_jac_heatfluxdiffusion) {
+    Jac_HeatFluxDiffusion = val_jac_heatfluxdiffusion;
+  }
+
   /*!
    * \brief Set the laminar viscosity.
    * \param[in] val_laminar_viscosity_i - Value of the laminar viscosity at point i.

SU2_CFD/include/numerics/flow/convection/fds.hpp

@@ -51,7 +51,7 @@ class CUpwFDSInc_Flow final : public CNumerics {
   Pressure_j, ProjVelocity,
   MeandRhodT, dRhodT_i, dRhodT_j, /*!< \brief Derivative of density w.r.t. temperature (variable density flows). */
   Temperature_i, Temperature_j,   /*!< \brief Temperature at node 0 and 1. */
-  MeanDensity, MeanPressure, MeanSoundSpeed, MeanBetaInc2, MeanEnthalpy, MeanCp, MeanTemperature; /*!< \brief Mean values of primitive variables. */
+  MeanDensity, MeanPressure, MeanSoundSpeed, MeanBetaInc2, MeanWorkingVar, MeanCp, MeanTemperature; /*!< \brief Mean values of primitive variables. */
   unsigned short iDim, iVar, jVar, kVar;
 
   su2double* Flux = nullptr;        /*!< \brief The flux / residual across the edge. */

SU2_CFD/include/numerics/flow/flow_diffusion.hpp

@@ -287,6 +287,7 @@ class CAvgGrad_Flow final : public CAvgGrad_Base {
 class CAvgGradInc_Flow final : public CAvgGrad_Base {
 private:
   su2double Mean_Thermal_Conductivity; /*!< \brief Mean value of the effective thermal conductivity. */
+  su2double Mean_Heat_Capacity;        /*!< \brief Mean value of the heat capacity. */
   bool energy;                         /*!< \brief computation with the energy equation. */
 
   /*!

SU2_CFD/include/numerics/flow/flow_sources.hpp

@@ -126,7 +126,8 @@ class CSourceGeneralAxisymmetric_Flow final : public CSourceAxisymmetric_Flow {
 class CSourceIncAxisymmetric_Flow final : public CSourceBase_Flow {
   bool implicit, /*!< \brief Implicit calculation. */
   viscous,       /*!< \brief Viscous incompressible flows. */
-  energy;        /*!< \brief computation with the energy equation. */
+  energy,        /*!< \brief computation with the energy equation. */
+  multicomponent; /*!< \brief multicomponent incompressible flows. */
 
 public:
   /*!

SU2_CFD/include/output/CFlowIncOutput.hpp

@@ -40,6 +40,7 @@ class CFlowIncOutput final: public CFlowOutput {
 private:
   TURB_MODEL turb_model;     /*!< \brief The kind of turbulence model*/
   bool heat;                 /*!< \brief Boolean indicating whether have a heat problem*/
+  bool multicomponent;       /*!< \brief Boolean indicating whether have a multicomponent problem*/
   bool weakly_coupled_heat;  /*!< \brief Boolean indicating whether have a weakly coupled heat equation*/
   bool flamelet;  /*!< \brief Boolean indicating whether we solve the flamelet equations */
   unsigned short streamwisePeriodic;   /*!< \brief Boolean indicating whether it is a streamwise periodic simulation. */

SU2_CFD/include/solvers/CFVMFlowSolverBase.hpp

@@ -69,7 +69,8 @@ class CFVMFlowSolverBase : public CSolver {
   su2double Mach_Inf = 0.0;          /*!< \brief Mach number at the infinity. */
   su2double Density_Inf = 0.0;       /*!< \brief Density at the infinity. */
   su2double Energy_Inf = 0.0;        /*!< \brief Energy at the infinity. */
-  su2double Temperature_Inf = 0.0;   /*!< \brief Energy at the infinity. */
+  su2double Temperature_Inf = 0.0;   /*!< \brief Temperature at the infinity. */
+  su2double Enthalpy_Inf = 0.0;      /*!< \brief Enthalpy at the infinity. */
   su2double Pressure_Inf = 0.0;      /*!< \brief Pressure at the infinity. */
   su2double* Velocity_Inf = nullptr; /*!< \brief Flow Velocity vector at the infinity. */
 

SU2_CFD/include/solvers/CIncEulerSolver.hpp

@@ -191,6 +191,19 @@ class CIncEulerSolver : public CFVMFlowSolverBase<CIncEulerVariable, ENUM_REGIME
                       CConfig *config,
                       unsigned short iMesh) final;
 
+  /*!
+   * \brief Recompute the extrapolated quantities, after MUSCL reconstruction,
+   *        in a more thermodynamically consistent way.
+   * \note This method is static to improve the chances of it being used in a
+   *       thread-safe manner.
+   * \param[in,out] fluidModel - The fluid model.
+   * \param[in] nDim - Number of physical dimensions.
+   * \param[in,out] primitive - Primitive variables.
+   * \param[in] scalar - scalar variable.
+   */
+  static void ComputeConsistentExtrapolation(CFluidModel* fluidModel, unsigned short nDim, su2double* primitive,
+                                             const su2double* scalar);
+
   /*!
    * \brief Source term integration.
    * \param[in] geometry - Geometrical definition of the problem.

SU2_CFD/include/variables/CIncEulerVariable.hpp

@@ -40,7 +40,7 @@
  */
 class CIncEulerVariable : public CFlowVariable {
 public:
-  static constexpr size_t MAXNVAR = 12;
+  static constexpr size_t MAXNVAR = 13;
 
   template <class IndexType>
   struct CIndices {
@@ -59,11 +59,11 @@ class CIncEulerVariable : public CFlowVariable {
     inline IndexType ThermalConductivity() const { return nDim+6; }
     inline IndexType CpTotal() const { return nDim+7; }
     inline IndexType CvTotal() const { return nDim+8; }
+    inline IndexType Enthalpy() const { return nDim + 9; }
 
     /*--- For compatible interface with NEMO. ---*/
     inline IndexType SpeciesDensities() const { return std::numeric_limits<IndexType>::max(); }
     inline IndexType Temperature_ve() const { return std::numeric_limits<IndexType>::max(); }
-    inline IndexType Enthalpy() const { return std::numeric_limits<IndexType>::max(); }
   };
 
  protected:
@@ -121,6 +121,14 @@ class CIncEulerVariable : public CFlowVariable {
     return val_temperature <= 0.0;
   }
 
+  /*!
+   * \brief Set the value of the enthalpy for multicomponent incompressible flows with energy equation.
+   * \param[in] iPoint - Point index.
+   */
+  inline void SetEnthalpy(unsigned long iPoint, su2double val_enthalpy) {
+    Primitive(iPoint, indices.Enthalpy()) = val_enthalpy;
+  }
+
   /*!
    * \brief Set the value of the beta coeffient for incompressible flows.
    * \param[in] iPoint - Point index.
@@ -153,6 +161,12 @@ class CIncEulerVariable : public CFlowVariable {
    */
   inline su2double GetTemperature(unsigned long iPoint) const final { return Primitive(iPoint, indices.Temperature()); }
 
+  /*!
+   * \brief Get the enthalpy of the flow.
+   * \return Value of the enthalpy of the flow.
+   */
+  inline su2double GetEnthalpy(unsigned long iPoint) const final { return Primitive(iPoint, indices.Enthalpy()); }
+
   /*!
    * \brief Get the velocity of the flow.
    * \param[in] iDim - Index of the dimension.

SU2_CFD/include/variables/CIncNSVariable.hpp

@@ -40,6 +40,7 @@ class CIncNSVariable final : public CIncEulerVariable {
 private:
   VectorType Tau_Wall;        /*!< \brief Magnitude of the wall shear stress from a wall function. */
   VectorType DES_LengthScale;
+  bool Energy_Multicomponent = false;
 
 public:
   /*!

SU2_CFD/src/fluid/CFluidScalar.cpp

@@ -45,6 +45,7 @@ CFluidScalar::CFluidScalar(su2double value_pressure_operating, const CConfig* co
     : CFluidModel(),
       n_species_mixture(config->GetnSpecies() + 1),
       Pressure_Thermodynamic(value_pressure_operating),
+      Ref_Temperature(config->GetStandard_RefTemperatureND()),
       GasConstant_Ref(config->GetGas_Constant_Ref()),
       Prandtl_Number(config->GetPrandtl_Turb()),
       wilke(config->GetKind_MixingViscosityModel() == MIXINGVISCOSITYMODEL::WILKE),
@@ -212,13 +213,43 @@ su2double CFluidScalar::ComputeMeanSpecificHeatCp(const su2double* val_scalars)
   return mean_cp;
 }
 
+su2double CFluidScalar::ComputeEnthalpyFromT(const su2double val_temperature, const su2double* val_scalars){
+  su2double val_Enthalpy = Cp * (val_temperature - Ref_Temperature);
+  return val_Enthalpy;
+}
+
+void CFluidScalar::ComputeTempFromEnthalpy(const su2double val_enthalpy, su2double* val_temperature,
+                                           const su2double* val_scalars) {
+  MassToMoleFractions(val_scalars);
+  su2double val_cp = ComputeMeanSpecificHeatCp(val_scalars);
+  *val_temperature = val_enthalpy / val_cp + Ref_Temperature;
+}
+
+void CFluidScalar::GetEnthalpyDiffusivity(su2double* enthalpy_diffusions) {
+  const su2double enthalpy_species_N = specificHeat[n_species_mixture - 1] * (Temperature - Ref_Temperature);
+  for (int iVar = 0; iVar < n_species_mixture - 1; iVar++) {
+    const su2double enthalpy_species_i = specificHeat[iVar] * (Temperature - Ref_Temperature);
+    enthalpy_diffusions[iVar] = Density * (enthalpy_species_i * massDiffusivity[iVar] -
+                                           enthalpy_species_N * massDiffusivity[n_species_mixture - 1]);
+  }
+}
+
+void CFluidScalar::GetGradEnthalpyDiffusivity(su2double* grad_enthalpy_diffusions){
+  for (int iVar = 0; iVar < n_species_mixture - 1; iVar++) {
+    grad_enthalpy_diffusions[iVar] = Density *
+                               (specificHeat[iVar] * massDiffusivity[iVar] -
+                                specificHeat[n_species_mixture - 1] * massDiffusivity[n_species_mixture - 1]);
+  }
+}
+
 void CFluidScalar::SetTDState_T(const su2double val_temperature, const su2double* val_scalars) {
   MassToMoleFractions(val_scalars);
   ComputeGasConstant();
   Temperature = val_temperature;
   Density = Pressure_Thermodynamic / (Temperature * Gas_Constant);
   Cp = ComputeMeanSpecificHeatCp(val_scalars);
   Cv = Cp - Gas_Constant;
+  Enthalpy = ComputeEnthalpyFromT(Temperature, val_scalars);
 
   if (wilke) {
     Mu = WilkeViscosity(val_scalars);

SU2_CFD/src/numerics/CNumerics.cpp

@@ -54,6 +54,7 @@ CNumerics::CNumerics(unsigned short val_nDim, unsigned short val_nVar,
   Prandtl_Lam = config->GetPrandtl_Lam();
   Prandtl_Turb = config->GetPrandtl_Turb();
   Gas_Constant = config->GetGas_ConstantND();
+  energy_multicomponent = ((config->GetKind_FluidModel() == FLUID_MIXTURE) && (config->GetEnergy_Equation()));
 
   tau = new su2double* [nDim];
   for (iDim = 0; iDim < nDim; iDim++)