equation_of_state_function.h

Go to the documentation of this file.

//
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// Copyright (C) 2023 - 2025 by the ryujin authors
//
 
#pragma once
 
#include <compile_time_options.h>
 
#include "equation_of_state.h"
 
#include <deal.II/base/function_parser.h>
 
namespace ryujin
{
  namespace EquationOfStateLibrary
  {
    class Function : public EquationOfState
    {
    public:
      using EquationOfState::pressure;
      using EquationOfState::specific_internal_energy;
      using EquationOfState::speed_of_sound;
      using EquationOfState::temperature;
 
      Function(const std::string &subsection)
          : EquationOfState("function", subsection)
      {
        p_expression_ = "(1.4 - 1.0) * rho * e";
        add_parameter(
            "pressure",
            p_expression_,
            "A function expression for the pressure as a function of density, "
            "rho, and specific internal energy, e: p(rho, e)");
 
        sie_expression_ = "p / (rho * (1.4 - 1.0))";
        add_parameter(
            "specific internal energy",
            sie_expression_,
            "A function expression for the specific internal energy as a "
            "function of density, rho, and pressure, p: e(rho, p)");
 
        se_expression_ = "287.052874 / (1.4 - 1.0) * (log((1.4 - 1.0) * rho * "
                         "e) - 1.4 * log(287.052874 * rho))";
        add_parameter("specific entropy",
                      se_expression_,
                      "A function expression for the specific entropy as a "
                      "function of density, "
                      "rho, and specific internal energy, e: s(rho, e)");
 
        e0_expression_ = "0";
        add_parameter("cold curve bound",
                      e0_expression_,
                      "A function expression for the cold curve bound as a "
                      "function of density: e_0(rho)");
 
        temperature_expression_ = "e * (1.4 - 1.0) / 287.052874";
        add_parameter("temperature",
                      temperature_expression_,
                      "A function expression for the temperature as a "
                      "function of density, rho, and specific internal energy, "
                      "e: T(rho, e)");
 
        sos_expression_ = "sqrt(1.4 * (1.4 - 1.0) * e)";
        add_parameter(
            "speed of sound",
            sos_expression_,
            "A function expression for the speed of sound as a function of "
            "density, rho, and specific internal energy, e: s(rho, e)");
 
        add_parameter(
            "covolume constant",
            this->covolume_constant_,
            "The maximum compressibility constant b for the equation of state");
 
        add_parameter("interpolatory reference pressure",
                      this->interpolation_pinfty_,
                      "The interpolatory reference pressure p_infty used when "
                      "constructing the interpolatory equation of state");
 
        add_parameter(
            "interpolatory reference specific internal energy",
            this->interpolation_q_,
            "The interpolatory reference specific internal energy q used when "
            "constructing the interpolatory equation of state");
 
        /*
         * Set up the muparser object with the final equation of state
         * description from the parameter file:
         */
        const auto set_up_muparser = [this] {
          p_function_ = std::make_unique<dealii::FunctionParser<2>>();
          p_function_->initialize(
              "rho,e", p_expression_, {{"b", this->covolume_constant_}});
 
          sie_function_ = std::make_unique<dealii::FunctionParser<2>>();
          sie_function_->initialize(
              "rho,p", sie_expression_, {{"b", this->covolume_constant_}});
 
          se_function_ = std::make_unique<dealii::FunctionParser<2>>();
          se_function_->initialize(
              "rho,e", se_expression_, {{"b", this->covolume_constant_}});
 
          e0_function_ = std::make_unique<dealii::FunctionParser<1>>();
          e0_function_->initialize(
              "rho", e0_expression_, {{"b", this->covolume_constant_}});
 
          temperature_function_ = std::make_unique<dealii::FunctionParser<2>>();
          temperature_function_->initialize("rho,e",
                                            temperature_expression_,
                                            {{"b", this->covolume_constant_}});
 
          sos_function_ = std::make_unique<dealii::FunctionParser<2>>();
          sos_function_->initialize("rho,e", sos_expression_, {});
        };
 
        set_up_muparser();
        ParameterAcceptor::parse_parameters_call_back.connect(set_up_muparser);
      }
 
      double pressure(double rho, double e) const final
      {
        return p_function_->value(dealii::Point<2>(rho, e));
      }
 
      double specific_internal_energy(double rho, double p) const final
      {
        return sie_function_->value(dealii::Point<2>(rho, p));
      }
 
      double specific_entropy(double rho, double e) const final
      {
        return se_function_->value(dealii::Point<2>(rho, e));
      }
 
      double cold_curve_bound(double rho) const final
      {
        return e0_function_->value(dealii::Point<1>(rho));
      }
 
      double temperature(double rho, double e) const final
      {
        return temperature_function_->value(dealii::Point<2>(rho, e));
      }
 
      double speed_of_sound(double rho, double e) const final
      {
        return sos_function_->value(dealii::Point<2>(rho, e));
      }
 
    private:
      std::string p_expression_;
      std::string sie_expression_;
      std::string se_expression_;
      std::string e0_expression_;
      std::string temperature_expression_;
      std::string sos_expression_;
 
      std::unique_ptr<dealii::FunctionParser<2>> p_function_;
      std::unique_ptr<dealii::FunctionParser<2>> sie_function_;
      std::unique_ptr<dealii::FunctionParser<2>> se_function_;
      std::unique_ptr<dealii::FunctionParser<1>> e0_function_;
      std::unique_ptr<dealii::FunctionParser<2>> temperature_function_;
      std::unique_ptr<dealii::FunctionParser<2>> sos_function_;
    };
  } // namespace EquationOfStateLibrary
} // namespace ryujin