Physics-informed neural networks for data-driven fluid model

Common/include/CConfig.hpp

@@ -538,6 +538,10 @@ class CConfig {
   ENUM_DATADRIVEN_METHOD Kind_DataDriven_Method;       /*!< \brief Method used for datset regression in data-driven fluid models. */
 
   su2double DataDriven_Relaxation_Factor; /*!< \brief Relaxation factor for Newton solvers in data-driven fluid models. */
+  su2double DataDriven_rho_init{-1.0},    /*!< \brief Optional initial density value for Newton solver in data-driven fluid model.*/
+            DataDriven_e_init{-1.0};      /*!< \brief Optional initial static energy value for Newton solver in data-driven fluid model.*/
+
+  bool UsePINN = false;       /*!< \brief Use physics-informed method for data-driven fluid modeling. */
 
   STRUCT_TIME_INT Kind_TimeIntScheme_FEA;    /*!< \brief Time integration for the FEA equations. */
   STRUCT_SPACE_ITE Kind_SpaceIteScheme_FEA;  /*!< \brief Iterative scheme for nonlinear structural analysis. */
@@ -3993,6 +3997,20 @@ class CConfig {
    */
   su2double GetRelaxation_DataDriven(void) const { return DataDriven_Relaxation_Factor; }
 
+  /*!
+   * \brief Get initial density value for Newton solver in data-driven fluid model.
+   * \return Initial density value.
+   */
+  su2double GetInitialDensity_DataDriven(void) const { return DataDriven_rho_init; }
+
+  /*!
+   * \brief Get initial static value for Newton solver in data-driven fluid model.
+   * \return Initial static value.
+   */
+  su2double GetInitialEnergy_DataDriven(void) const { return DataDriven_e_init; }
+
+  bool Use_PINN(void) const { return UsePINN; }
+
   /*!
    * \brief Returns the name of the fluid we are using in CoolProp.
    */
@@ -7083,6 +7101,12 @@ class CConfig {
    */
   void SetGiles_Var1(su2double newVar1, const string& val_marker);
 
+  /*!
+   * \brief Set the var 1 for Riemann BC.
+   * \param[in] val_marker - Index corresponding to the Riemann BC.
+   */
+  void SetRiemann_Var1(su2double newVar1, const string& val_marker);
+
   /*!
    * \brief Get the relax factor for the average component for the Giles BC.
    * \param[in] val_marker - Index corresponding to the Giles BC.

Common/src/CConfig.cpp

@@ -1197,7 +1197,13 @@ void CConfig::SetConfig_Options() {
   /*!\brief FILENAME_INTERPOLATOR \n DESCRIPTION: Input file for the interpolation method. \n \ingroup Config*/
   addStringListOption("FILENAMES_INTERPOLATOR", n_Datadriven_files, DataDriven_Method_FileNames);
   /*!\brief DATADRIVEN_NEWTON_RELAXATION \n DESCRIPTION: Relaxation factor for Newton solvers in data-driven fluid model. \n \ingroup Config*/
-  addDoubleOption("DATADRIVEN_NEWTON_RELAXATION", DataDriven_Relaxation_Factor, 0.05);
+  addDoubleOption("DATADRIVEN_NEWTON_RELAXATION", DataDriven_Relaxation_Factor, 1.0);
+  /*!\brief DATADRIVEN_INITIAL_DENSITY \n DESCRIPTION: Optional initial value for fluid density used for the Newton solver processes in the data-driven fluid model. */
+  addDoubleOption("DATADRIVEN_INITIAL_DENSITY", DataDriven_rho_init, -1.0);
+  /*!\brief DATADRIVEN_INITIAL_ENERGY \n DESCRIPTION: Optional initial value for fluid static energy used for the Newton solver processes in the data-driven fluid model. */
+  addDoubleOption("DATADRIVEN_INITIAL_ENERGY", DataDriven_e_init, -1.0);
+  /*!\biref USE_PINN \n DESCRIPTION: Use physics-informed approach for the entropy-based fluid model. \n \ingroup Config*/
+  addBoolOption("USE_PINN",UsePINN, false);
 
   /*!\brief CONFINEMENT_PARAM \n DESCRIPTION: Input Confinement Parameter for Vorticity Confinement*/
   addDoubleOption("CONFINEMENT_PARAM", Confinement_Param, 0.0);
@@ -9124,6 +9130,13 @@ void CConfig::SetOutlet_Pressure(su2double val_pressure, const string& val_marke
       Outlet_Pressure[iMarker_Outlet] = val_pressure;
 }
 
+void CConfig::SetRiemann_Var1(su2double newVar1, const string& val_marker) {
+  unsigned short iMarker_Riemann;
+  for (iMarker_Riemann = 0; iMarker_Riemann < nMarker_Riemann; iMarker_Riemann++)
+    if (Marker_Riemann[iMarker_Riemann] == val_marker) break;
+  Riemann_Var1[iMarker_Riemann] = newVar1;
+}
+
 su2double CConfig::GetRiemann_Var1(const string& val_marker) const {
   unsigned short iMarker_Riemann;
   for (iMarker_Riemann = 0; iMarker_Riemann < nMarker_Riemann; iMarker_Riemann++)

SU2_CFD/include/fluid/CDataDrivenFluid.hpp

@@ -62,6 +62,12 @@ class CDataDrivenFluid final : public CFluidModel {
       rho_min, rho_max,        /*!< \brief Minimum and maximum density values in data set. */
       e_min, e_max;            /*!< \brief Minimum and maximum energy values in data set. */
 
+  bool custom_init_rho{false},
+       custom_init_e{false};
+  su2double val_custom_init_rho,
+            val_custom_init_e,
+            rho_median,
+            e_median;
   unsigned long MaxIter_Newton; /*!< \brief Maximum number of iterations for Newton solvers. */
 
   su2double dsde_rho, /*!< \brief Entropy derivative w.r.t. density. */
@@ -77,6 +83,8 @@ class CDataDrivenFluid final : public CFluidModel {
             P_middle,       /*!< \brief Pressure computed from the centre of the data set. */
             T_middle;       /*!< \brief Temperature computed from the centre of the data set. */
 
+  su2double gas_constant_config,
+            gamma_config;
   su2double Enthalpy, /*!< \brief Fluid enthalpy value [J kg^-1] */
       dhdrho_e,       /*!< \brief Enthalpy derivative w.r.t. density. */
       dhde_rho;       /*!< \brief Enthalpy derivative w.r.t. static energy. */
@@ -87,6 +95,10 @@ class CDataDrivenFluid final : public CFluidModel {
 
   vector<su2double*> outputs_rhoe; /*!< \brief Pointers to output variables. */
 
+  vector<vector<su2double*>> dsdrhoe;
+  vector<vector<vector<su2double*>>> d2sdrhoe2;
+
+  bool use_MLP_derivatives;
   /*--- Class variables for the multi-layer perceptron method ---*/
 #ifdef USE_MLPCPP
   MLPToolbox::CLookUp_ANN* lookup_mlp; /*!< \brief Multi-layer perceptron collection. */
@@ -158,6 +170,7 @@ class CDataDrivenFluid final : public CFluidModel {
   void Run_Newton_Solver(su2double Y_target, su2double* Y, su2double* X, su2double* dYdX);
 
   void ComputeIdealGasQuantities();
+
  public:
   /*!
    * \brief Constructor of the class.
@@ -213,6 +226,15 @@ class CDataDrivenFluid final : public CFluidModel {
    */
   void SetTDState_Ps(su2double P, su2double s) override;
 
+  /*!
+   * \brief compute some derivatives of enthalpy and entropy needed for subsonic inflow BC
+   * \param[in] InputSpec - Input pair for FLP calls ("Pv").
+   * \param[in] th1 - first thermodynamic variable (P).
+   * \param[in] th2 - second thermodynamic variable (v).
+   *
+   */
+  void ComputeDerivativeNRBC_Prho(su2double P, su2double rho) override;
+
   /*!
    * \brief Get fluid model extrapolation instance.
    * \return Query point lies outside fluid model data range.

SU2_CFD/include/iteration/CFluidIteration.hpp

@@ -108,14 +108,23 @@ class CFluidIteration : public CIteration {
                unsigned short val_iInst) override;
 
   /*!
-   * \brief Monitors turbo computation (pressure and turbo ramps).
+   * \brief Monitors turbo computation (turbo ramp).
    * \param[in] geometry_container - Geometrical definition of the problem
    * \param[in] config_container - Defintion of the particular problem
    * \param[in] ExtIter - The current iteration of the problem
    * \param[in] iZone - The current zone
    */
   void TurboMonitor(CGeometry**** geometry_container, CConfig** config_container, unsigned long ExtIter, unsigned short iZone);
 
+  /*!
+   * \brief Update adaptive boundary condition values.
+   * \param[in] geometry_container - Geometrical definition of the problem
+   * \param[in] config_container - Defintion of the particular problem
+   * \param[in] ExtIter - The current iteration of the problem
+   * \param[in] iZone - The current zone
+   */
+  void UpdateBoundaryConditions(CGeometry**** geometry_container, CConfig** config_container, unsigned long ExtIter, unsigned short iZone);
+
   /*!
    * \brief Computes turboperformance.
    */