FGAtmosphere.h

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/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 Header:       FGAtmosphere.h
 Author:       Jon Berndt
 Date started: 6/2011
 
 ------------- Copyright (C) 2011  Jon S. Berndt (jon@jsbsim.org) -------------
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU Lesser General Public License as published by the Free
 Software Foundation; either version 2 of the License, or (at your option) any
 later version.
 
 This program is distributed in the hope that it will be useful, but WITHOUT
 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
 details.
 
 You should have received a copy of the GNU Lesser General Public License along
 with this program; if not, write to the Free Software Foundation, Inc., 59
 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 
 Further information about the GNU Lesser General Public License can also be
 found on the world wide web at http://www.gnu.org.
 
HISTORY
--------------------------------------------------------------------------------
5/2011   JSB   Created
 
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SENTRY
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#ifndef FGATMOSPHERE_H
#define FGATMOSPHERE_H
 
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
INCLUDES
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#include "models/FGModel.h"
 
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
FORWARD DECLARATIONS
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namespace JSBSim {
 
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
CLASS DOCUMENTATION
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/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
CLASS DECLARATION
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class FGAtmosphere : public FGModel {
public:

  enum eTemperature {eNoTempUnit=0, eFahrenheit, eCelsius, eRankine, eKelvin};

  enum ePressure {eNoPressUnit=0, ePSF, eMillibars, ePascals, eInchesHg};

  FGAtmosphere(FGFDMExec*);

  virtual ~FGAtmosphere();

  bool Run(bool Holding) override;
 
  bool InitModel(void) override;
 
  //  *************************************************************************
  // @{
  virtual double GetTemperature() const {return Temperature;}

  virtual double GetTemperature(double altitude) const = 0; 

  virtual double GetTemperatureSL() const { return SLtemperature; }

  virtual double GetTemperatureRatio() const { return GetTemperature()/SLtemperature; }

  virtual double GetTemperatureRatio(double h) const { return GetTemperature(h)/SLtemperature; }

  virtual void SetTemperatureSL(double t, eTemperature unit=eFahrenheit);

  virtual void SetTemperature(double t, double h, eTemperature unit=eFahrenheit) = 0;
 
  //  *************************************************************************


  virtual double GetPressure(void) const {return Pressure;}

  virtual double GetPressure(double altitude) const = 0;
 
  // Returns the sea level pressure in target units, default in psf.
  virtual double GetPressureSL(ePressure to=ePSF) const { return ConvertFromPSF(SLpressure, to);  }

  virtual double GetPressureRatio(void) const { return Pressure/SLpressure; }

  virtual void SetPressureSL(ePressure unit, double pressure);
 
  //  *************************************************************************


  virtual double GetDensity(void)  const {return Density;}

  virtual double GetDensity(double altitude) const;

  virtual double GetDensitySL(void)  const { return SLdensity; }

  virtual double GetDensityRatio(void) const { return Density/SLdensity; }
 
  //  *************************************************************************


  virtual double GetSoundSpeed(void) const {return Soundspeed;}

  virtual double GetSoundSpeed(double altitude) const;
  
  virtual double GetSoundSpeedSL(void) const { return SLsoundspeed; }

  virtual double GetSoundSpeedRatio(void) const { return Soundspeed/SLsoundspeed; }
 
  //  *************************************************************************


  virtual double GetAbsoluteViscosity(void) const {return Viscosity;}

  virtual double GetKinematicViscosity(void) const {return KinematicViscosity;}
 
  virtual double GetDensityAltitude() const {return DensityAltitude;}
 
  virtual double GetPressureAltitude() const {return PressureAltitude;}
 
  struct Inputs {
    double altitudeASL;
  } in;
 
  static constexpr double StdDaySLtemperature = 518.67;
  static constexpr double StdDaySLpressure = 2116.228;
  static const double StdDaySLsoundspeed;
 
protected:
  double    SLtemperature,    SLdensity,    SLpressure,    SLsoundspeed; // Sea level conditions
  double      Temperature,      Density,      Pressure,      Soundspeed; // Current actual conditions at altitude
 
  double PressureAltitude;
  double DensityAltitude;
 
  static constexpr double SutherlandConstant = 198.72;  // deg Rankine
  static constexpr double Beta = 2.269690E-08; // slug/(sec ft R^0.5)
  double Viscosity, KinematicViscosity;

  virtual void Calculate(double altitude);

  virtual double CalculateDensityAltitude(double density, double geometricAlt) { return geometricAlt; }

  virtual double CalculatePressureAltitude(double pressure, double geometricAlt) { return geometricAlt; }

  double ConvertToRankine(double t, eTemperature unit) const;
  
  double ConvertFromRankine(double t, eTemperature unit) const;

  double ConvertToPSF(double t, ePressure unit=ePSF) const;

  double ConvertFromPSF(double t, ePressure unit=ePSF) const;



  static constexpr double Rstar = 8.31432 * kgtoslug / KelvinToRankine(fttom * fttom);
  static constexpr double Mair = 28.9645 * kgtoslug / 1000.0;
  static constexpr double g0 = 9.80665 / fttom;
  static double Reng;
 
  static constexpr double SHRatio = 1.4;
 
  virtual void bind(void);
  void Debug(int from) override;
};
 
} // namespace JSBSim
 
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
#endif