barotropic_equation_of_state_isentropic.h

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//
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// Copyright (C) 2025 - 2026 by the ryujin authors
//
 
#pragma once
 
#include <ryujin/base/compile_time_options.h>
#include <ryujin/euler_barotropic/barotropic_equation_of_state.h>
 
namespace ryujin
{
  namespace BarotropicEquationsOfState
  {
    class Isentropic : public BarotropicEquationOfState
    {
    public:
      Isentropic(const std::string &subsection)
          : BarotropicEquationOfState("isentropic", subsection)
      {
        k_ = 1.;
        this->add_parameter("k", k_, "Scaling factor k");
 
        gamma_ = 7. / 5.;
        this->add_parameter("gamma", gamma_, "The ratio of specific heats");
      }
 
      double specific_internal_energy(double rho) const final
      {
        return k_ / (gamma_ - 1) * std::pow(rho, gamma_ - 1.);
      }
 
      double pressure(double rho) const final
      {
        return k_ * std::pow(rho, gamma_);
      }
 
      double speed_of_sound(double rho) const final
      {
        return std::sqrt(gamma_ * k_ * std::pow(rho, gamma_ - 1.));
      }
 
    private:
      double k_;
      double gamma_;
    };
  } // namespace BarotropicEquationsOfState
} // namespace ryujin