FGAtmosphere Class Reference

Detailed Description

Models an empty, abstract base atmosphere class.

Properties

• atmosphere/T-R The current modeled temperature in degrees Rankine.
• atmosphere/rho-slugs_ft3
• atmosphere/P-psf
• atmosphere/a-fps
• atmosphere/T-sl-R
• atmosphere/rho-sl-slugs_ft3
• atmosphere/P-sl-psf
• atmosphere/a-sl-fps
• atmosphere/theta
• atmosphere/sigma
• atmosphere/delta
• atmosphere/a-ratio

Author

Jon Berndt

Definition at line 76 of file FGAtmosphere.h.

#include <FGAtmosphere.h>

Inheritance diagram for FGAtmosphere:

Collaboration diagram for FGAtmosphere:

Classes
struct	Inputs

Public Types
enum	ePressure {   eNoPressUnit =0 , ePSF , eMillibars , ePascals ,   eInchesHg }
	Enums for specifying pressure units. More...
enum	eTemperature {   eNoTempUnit =0 , eFahrenheit , eCelsius , eRankine ,   eKelvin }
	Enums for specifying temperature units. More...
Public Types inherited from FGJSBBase
enum	{ eL = 1 , eM , eN }
	Moments L, M, N. More...
enum	{ eP = 1 , eQ , eR }
	Rates P, Q, R. More...
enum	{ eU = 1 , eV , eW }
	Velocities U, V, W. More...
enum	{ eX = 1 , eY , eZ }
	Positions X, Y, Z. More...
enum	{ ePhi = 1 , eTht , ePsi }
	Euler angles Phi, Theta, Psi. More...
enum	{ eDrag = 1 , eSide , eLift }
	Stability axis forces, Drag, Side force, Lift. More...
enum	{ eRoll = 1 , ePitch , eYaw }
	Local frame orientation Roll, Pitch, Yaw. More...
enum	{ eNorth = 1 , eEast , eDown }
	Local frame position North, East, Down. More...
enum	{ eLat = 1 , eLong , eRad }
	Locations Radius, Latitude, Longitude. More...
enum	{   inNone = 0 , inDegrees , inRadians , inMeters ,   inFeet }
	Conversion specifiers. More...

Public Member Functions
	FGAtmosphere (FGFDMExec *)
	Constructor.
virtual	~FGAtmosphere ()
	Destructor.
bool	InitModel (void) override
bool	Run (bool Holding) override
	Runs the atmosphere forces model; called by the Executive.
Temperature access functions.
There are several ways to get the temperature, and several modeled temperature values that can be retrieved.
virtual double	GetTemperature () const
	Returns the actual, modeled temperature at the current altitude in degrees Rankine.
virtual double	GetTemperature (double altitude) const =0
	Returns the actual modeled temperature in degrees Rankine at a specified altitude.
virtual double	GetTemperatureSL () const
	Returns the actual, modeled sea level temperature in degrees Rankine.
virtual double	GetTemperatureRatio () const
	Returns the ratio of the at-current-altitude temperature as modeled over the sea level value.
virtual double	GetTemperatureRatio (double h) const
	Returns the ratio of the temperature as modeled at the supplied altitude over the sea level value.
virtual void	SetTemperatureSL (double t, eTemperature unit=eFahrenheit)
	Sets the Sea Level temperature.
virtual void	SetTemperature (double t, double h, eTemperature unit=eFahrenheit)=0
	Sets the temperature at the supplied altitude.
Pressure access functions.
virtual double	GetPressure (void) const
	Returns the pressure in psf.
virtual double	GetPressure (double altitude) const =0
	Returns the pressure at a specified altitude in psf.
virtual double	GetPressureSL (ePressure to=ePSF) const
virtual double	GetPressureRatio (void) const
	Returns the ratio of at-altitude pressure over the sea level value.
virtual void	SetPressureSL (ePressure unit, double pressure)
	Sets the sea level pressure for modeling.
Density access functions.
virtual double	GetDensity (void) const
	Returns the density in slugs/ft^3.
virtual double	GetDensity (double altitude) const
	Returns the density in slugs/ft^3 at a given altitude in ft.
virtual double	GetDensitySL (void) const
	Returns the sea level density in slugs/ft^3.
virtual double	GetDensityRatio (void) const
	Returns the ratio of at-altitude density over the sea level value.
Speed of sound access functions.
virtual double	GetSoundSpeed (void) const
	Returns the speed of sound in ft/sec.
virtual double	GetSoundSpeed (double altitude) const
	Returns the speed of sound in ft/sec at a given altitude in ft.
virtual double	GetSoundSpeedSL (void) const
	Returns the sea level speed of sound in ft/sec.
virtual double	GetSoundSpeedRatio (void) const
	Returns the ratio of at-altitude sound speed over the sea level value.
Public Member Functions inherited from FGModel
	FGModel (FGFDMExec *)
	Constructor.
	~FGModel () override
	Destructor.
virtual SGPath	FindFullPathName (const SGPath &path) const
FGFDMExec *	GetExec (void)
const std::string &	GetName (void)
unsigned int	GetRate (void)
	Get the output rate for the model in frames.
bool	InitModel (void) override
virtual bool	Load (Element *el)
void	SetPropertyManager (std::shared_ptr< FGPropertyManager > fgpm)
void	SetRate (unsigned int tt)
	Set the ouput rate for the model in frames.
Public Member Functions inherited from FGModelFunctions
std::string	GetFunctionStrings (const std::string &delimeter) const
	Gets the strings for the current set of functions.
std::string	GetFunctionValues (const std::string &delimeter) const
	Gets the function values.
std::shared_ptr< FGFunction >	GetPreFunction (const std::string &name)
	Get one of the "pre" function.
bool	Load (Element *el, FGFDMExec *fdmex, std::string prefix="")
void	PostLoad (Element *el, FGFDMExec *fdmex, std::string prefix="")
void	PreLoad (Element *el, FGFDMExec *fdmex, std::string prefix="")
void	RunPostFunctions (void)
void	RunPreFunctions (void)
Public Member Functions inherited from FGJSBBase
	FGJSBBase ()
	Constructor for FGJSBBase.
virtual	~FGJSBBase ()
	Destructor for FGJSBBase.
void	disableHighLighting (void)
	Disables highlighting in the console output.

Viscosity access functions.
struct JSBSim::FGAtmosphere::Inputs	in
const double	StdDaySLsoundspeed
static constexpr double	StdDaySLtemperature = 518.67
static constexpr double	StdDaySLpressure = 2116.228
static constexpr double	SHRatio = 1.4
double	SLtemperature = 1.8
double	SLdensity = 1.0
double	SLpressure = 1.0
double	SLsoundspeed = 1.0
double	Temperature = 1.8
double	Density = 0.0
double	Pressure = 0.0
double	Soundspeed = 0.0
double	PressureAltitude = 0.0
double	DensityAltitude = 0.0
double	Viscosity = 0.0
double	KinematicViscosity = 0.0
static constexpr double	SutherlandConstant = 198.72
static constexpr double	Beta = 2.269690E-08
virtual double	GetAbsoluteViscosity (void) const
	Returns the absolute viscosity.
virtual double	GetKinematicViscosity (void) const
	Returns the kinematic viscosity.
virtual double	GetDensityAltitude () const
virtual double	GetPressureAltitude () const
virtual void	Calculate (double altitude)
	Calculate the atmosphere for the given altitude.
virtual double	CalculateDensityAltitude (double density, double geometricAlt)
	Calculates the density altitude given any temperature or pressure bias.
virtual double	CalculatePressureAltitude (double pressure, double geometricAlt)
	Calculates the pressure altitude given any temperature or pressure bias.
double	ConvertToRankine (double t, eTemperature unit) const
	Converts to Rankine from one of several unit systems.
double	ConvertFromRankine (double t, eTemperature unit) const
	Converts from Rankine to one of several unit systems.
double	ConvertToPSF (double t, ePressure unit=ePSF) const
	Converts to PSF (pounds per square foot) from one of several unit systems.
double	ConvertFromPSF (double t, ePressure unit=ePSF) const
	Converts from PSF (pounds per square foot) to one of several unit systems.
double	ValidatePressure (double p, const std::string &msg, bool quiet=false) const
	Check that the pressure is within plausible boundaries.
double	ValidateTemperature (double t, const std::string &msg, bool quiet=false) const
	Check that the temperature is within plausible boundaries.

ISA constants
static constexpr double	StdDaySLdensity = StdDaySLpressure / (Reng0 * StdDaySLtemperature)
double	Reng = Reng0
static constexpr double	Rstar = 8.31432 * kgtoslug / KelvinToRankine(fttom * fttom)
	Universal gas constant - ft*lbf/R/mol.
static constexpr double	Mair = 28.9645 * kgtoslug / 1000.0
	Mean molecular weight for air - slug/mol.
static constexpr double	g0 = 9.80665 / fttom
	Sea-level acceleration of gravity - ft/s^2.
static constexpr double	Reng0 = Rstar / Mair
	Specific gas constant for air - ft*lbf/slug/R.
virtual void	bind (void)
void	Debug (int from) override

Additional Inherited Members
Static Public Member Functions inherited from FGJSBBase
static const std::string &	GetVersion (void)
	Returns the version number of JSBSim.
static constexpr double	KelvinToFahrenheit (double kelvin)
	Converts from degrees Kelvin to degrees Fahrenheit.
static constexpr double	CelsiusToRankine (double celsius)
	Converts from degrees Celsius to degrees Rankine.
static constexpr double	RankineToCelsius (double rankine)
	Converts from degrees Rankine to degrees Celsius.
static constexpr double	KelvinToRankine (double kelvin)
	Converts from degrees Kelvin to degrees Rankine.
static constexpr double	RankineToKelvin (double rankine)
	Converts from degrees Rankine to degrees Kelvin.
static constexpr double	FahrenheitToCelsius (double fahrenheit)
	Converts from degrees Fahrenheit to degrees Celsius.
static constexpr double	CelsiusToFahrenheit (double celsius)
	Converts from degrees Celsius to degrees Fahrenheit.
static constexpr double	CelsiusToKelvin (double celsius)
	Converts from degrees Celsius to degrees Kelvin.
static constexpr double	KelvinToCelsius (double kelvin)
	Converts from degrees Kelvin to degrees Celsius.
static constexpr double	FeetToMeters (double measure)
	Converts from feet to meters.
static bool	EqualToRoundoff (double a, double b)
	Finite precision comparison.
static bool	EqualToRoundoff (float a, float b)
	Finite precision comparison.
static bool	EqualToRoundoff (float a, double b)
	Finite precision comparison.
static bool	EqualToRoundoff (double a, float b)
	Finite precision comparison.
static constexpr double	Constrain (double min, double value, double max)
	Constrain a value between a minimum and a maximum value.
static constexpr double	sign (double num)
Static Public Attributes inherited from FGJSBBase
static char	highint [5] = {27, '[', '1', 'm', '\0' }
	highlights text
static char	halfint [5] = {27, '[', '2', 'm', '\0' }
	low intensity text
static char	normint [6] = {27, '[', '2', '2', 'm', '\0' }
	normal intensity text
static char	reset [5] = {27, '[', '0', 'm', '\0' }
	resets text properties
static char	underon [5] = {27, '[', '4', 'm', '\0' }
	underlines text
static char	underoff [6] = {27, '[', '2', '4', 'm', '\0' }
	underline off
static char	fgblue [6] = {27, '[', '3', '4', 'm', '\0' }
	blue text
static char	fgcyan [6] = {27, '[', '3', '6', 'm', '\0' }
	cyan text
static char	fgred [6] = {27, '[', '3', '1', 'm', '\0' }
	red text
static char	fggreen [6] = {27, '[', '3', '2', 'm', '\0' }
	green text
static char	fgdef [6] = {27, '[', '3', '9', 'm', '\0' }
	default text
static short	debug_lvl = 1
Protected Member Functions inherited from FGModel
bool	Upload (Element *el, bool preLoad)
	Uploads this model in memory.
Static Protected Member Functions inherited from FGJSBBase
static std::string	CreateIndexedPropertyName (const std::string &Property, int index)
Protected Attributes inherited from FGModel
unsigned int	exe_ctr
FGFDMExec *	FDMExec
std::string	Name
std::shared_ptr< FGPropertyManager >	PropertyManager
unsigned int	rate
Protected Attributes inherited from FGModelFunctions
FGPropertyReader	LocalProperties
std::vector< std::shared_ptr< FGFunction > >	PostFunctions
std::vector< std::shared_ptr< FGFunction > >	PreFunctions
Static Protected Attributes inherited from FGJSBBase
static constexpr double	radtodeg = 180. / M_PI
static constexpr double	degtorad = M_PI / 180.
static constexpr double	hptoftlbssec = 550.0
static constexpr double	psftoinhg = 0.014138
static constexpr double	psftopa = 47.88
static constexpr double	fttom = 0.3048
static constexpr double	ktstofps = 1852./(3600*fttom)
static constexpr double	fpstokts = 1.0 / ktstofps
static constexpr double	inchtoft = 1.0/12.0
static constexpr double	m3toft3 = 1.0/(fttom*fttom*fttom)
static constexpr double	in3tom3 = inchtoft*inchtoft*inchtoft/m3toft3
static constexpr double	inhgtopa = 3386.38
static constexpr double	slugtolb = 32.174049
	Note that definition of lbtoslug by the inverse of slugtolb and not to a different constant you can also get from some tables will make lbtoslug*slugtolb == 1 up to the magnitude of roundoff.
static constexpr double	lbtoslug = 1.0/slugtolb
static constexpr double	kgtolb = 2.20462
static constexpr double	kgtoslug = 0.06852168
static const std::string	needed_cfg_version = "2.0"
static const std::string	JSBSim_version = JSBSIM_VERSION " " __DATE__ " " __TIME__

Member Enumeration Documentation

ePressure

enum ePressure

Enums for specifying pressure units.

Definition at line 83 of file FGAtmosphere.h.

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

eTemperature

enum eTemperature

Enums for specifying temperature units.

Definition at line 80 of file FGAtmosphere.h.

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

Constructor & Destructor Documentation

FGAtmosphere()

FGAtmosphere

(

FGFDMExec *

fdmex

)

Constructor.

Definition at line 56 of file FGAtmosphere.cpp.

  : FGModel(fdmex),
    StdDaySLsoundspeed(sqrt(SHRatio*Reng0*StdDaySLtemperature))
{
  Name = "FGAtmosphere";
 
  bind();
  Debug(0);
}

~FGAtmosphere()

~FGAtmosphere ( )

virtual

Destructor.

Definition at line 68 of file FGAtmosphere.cpp.

{
  Debug(1);
}

Member Function Documentation

bind()

void bind ( void  )

protectedvirtual

Definition at line 314 of file FGAtmosphere.cpp.

{
  PropertyManager->Tie("atmosphere/T-R", this, &FGAtmosphere::GetTemperature);
  PropertyManager->Tie("atmosphere/rho-slugs_ft3", this, &FGAtmosphere::GetDensity);
  PropertyManager->Tie("atmosphere/P-psf", this, &FGAtmosphere::GetPressure);
  PropertyManager->Tie("atmosphere/a-fps", this, &FGAtmosphere::GetSoundSpeed);
  PropertyManager->Tie("atmosphere/T-sl-R", this, &FGAtmosphere::GetTemperatureSL);
  PropertyManager->Tie("atmosphere/rho-sl-slugs_ft3", this, &FGAtmosphere::GetDensitySL);
  PropertyManager->Tie("atmosphere/a-sl-fps", this, &FGAtmosphere::GetSoundSpeedSL);
  PropertyManager->Tie("atmosphere/theta", this, &FGAtmosphere::GetTemperatureRatio);
  PropertyManager->Tie("atmosphere/sigma", this, &FGAtmosphere::GetDensityRatio);
  PropertyManager->Tie("atmosphere/delta", this, &FGAtmosphere::GetPressureRatio);
  PropertyManager->Tie("atmosphere/a-ratio", this, &FGAtmosphere::GetSoundSpeedRatio);
  PropertyManager->Tie("atmosphere/density-altitude", this, &FGAtmosphere::GetDensityAltitude);
  PropertyManager->Tie("atmosphere/pressure-altitude", this, &FGAtmosphere::GetPressureAltitude);
}

Calculate()

void Calculate ( double  altitude )

protectedvirtual

Calculate the atmosphere for the given altitude.

Reimplemented in FGMSIS, and FGStandardAtmosphere.

Definition at line 139 of file FGAtmosphere.cpp.

{
  FGPropertyNode* node = PropertyManager->GetNode();
  double t =0.0;
  if (!PropertyManager->HasNode("atmosphere/override/temperature"))
    t = GetTemperature(altitude);
  else
    t = node->GetDouble("atmosphere/override/temperature");
  Temperature = ValidateTemperature(t, "", true);
 
  double p = 0.0;
  if (!PropertyManager->HasNode("atmosphere/override/pressure"))
    p = GetPressure(altitude);
  else
    p = node->GetDouble("atmosphere/override/pressure");
  Pressure = ValidatePressure(p, "", true);
 
  if (!PropertyManager->HasNode("atmosphere/override/density"))
    Density = Pressure/(Reng*Temperature);
  else
    Density = node->GetDouble("atmosphere/override/density");
 
  Soundspeed  = sqrt(SHRatio*Reng*Temperature);
  PressureAltitude = CalculatePressureAltitude(Pressure, altitude);
  DensityAltitude = CalculateDensityAltitude(Density, altitude);
 
  Viscosity = Beta * pow(Temperature, 1.5) / (SutherlandConstant + Temperature);
  KinematicViscosity = Viscosity / Density;
}

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CalculateDensityAltitude()

virtual double CalculateDensityAltitude ( double  density, double  geometricAlt  )

inlineprotectedvirtual

Calculates the density altitude given any temperature or pressure bias.

Calculated density for the specified geometric altitude given any temperature or pressure biases is passed in.

Parameters

density
geometricAlt

Reimplemented in FGStandardAtmosphere.

Definition at line 247 of file FGAtmosphere.h.

{ return geometricAlt; }

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CalculatePressureAltitude()

virtual double CalculatePressureAltitude ( double  pressure, double  geometricAlt  )

inlineprotectedvirtual

Calculates the pressure altitude given any temperature or pressure bias.

Calculated pressure for the specified geometric altitude given any temperature or pressure biases is passed in.

Parameters

pressure
geometricAlt

Reimplemented in FGStandardAtmosphere.

Definition at line 254 of file FGAtmosphere.h.

{ return geometricAlt; }

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ConvertFromPSF()

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

protected

Converts from PSF (pounds per square foot) to one of several unit systems.

Definition at line 288 of file FGAtmosphere.cpp.

{
  double targetPressure=0; // Pressure
 
  switch(unit) {
  case ePSF:
    targetPressure = p;
    break;
  case eMillibars:
    targetPressure = p/2.08854342;
    break;
  case ePascals:
    targetPressure = p/0.0208854342;
    break;
  case eInchesHg:
    targetPressure = p/70.7180803;
    break;
  default:
    throw BaseException("Undefined pressure unit given");
  }
 
  return targetPressure;
}

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ConvertFromRankine()

double ConvertFromRankine ( double  t, eTemperature  unit  ) const

protected

Converts from Rankine to one of several unit systems.

Definition at line 236 of file FGAtmosphere.cpp.

{
  double targetTemp=0;
 
  switch(unit) {
  case eFahrenheit:
    targetTemp = t - 459.67;
    break;
  case eCelsius:
    targetTemp = t/1.8 - 273.15;
    break;
  case eRankine:
    targetTemp = t;
    break;
  case eKelvin:
    targetTemp = t/1.8;
    break;
  default:
    throw BaseException("Undefined temperature unit given");
  }
 
  return targetTemp;
}

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ConvertToPSF()

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

protected

Converts to PSF (pounds per square foot) from one of several unit systems.

Definition at line 262 of file FGAtmosphere.cpp.

{
  double targetPressure=0; // Pressure in PSF
 
  switch(unit) {
  case ePSF:
    targetPressure = p;
    break;
  case eMillibars:
    targetPressure = p*2.08854342;
    break;
  case ePascals:
    targetPressure = p*0.0208854342;
    break;
  case eInchesHg:
    targetPressure = p*70.7180803;
    break;
  default:
    throw BaseException("Undefined pressure unit given");
  }
 
  return targetPressure;
}

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ConvertToRankine()

double ConvertToRankine ( double  t, eTemperature  unit  ) const

protected

Converts to Rankine from one of several unit systems.

Definition at line 210 of file FGAtmosphere.cpp.

{
  double targetTemp=0; // in degrees Rankine
 
  switch(unit) {
  case eFahrenheit:
    targetTemp = t + 459.67;
    break;
  case eCelsius:
    targetTemp = (t + 273.15) * 1.8;
    break;
  case eRankine:
    targetTemp = t;
    break;
  case eKelvin:
    targetTemp = t*1.8;
    break;
  default:
    throw BaseException("Undefined temperature unit given");
  }
 
  return targetTemp;
}

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Debug()

void Debug ( int  from )

overrideprotectedvirtual

Reimplemented from FGModel.

Definition at line 350 of file FGAtmosphere.cpp.

{
  if (debug_lvl <= 0) return;
 
  if (debug_lvl & 1) { // Standard console startup message output
    if (from == 0) { // Constructor
    }
  }
  if (debug_lvl & 2 ) { // Instantiation/Destruction notification
    if (from == 0) std::cout << "Instantiated: FGAtmosphere" << std::endl;
    if (from == 1) std::cout << "Destroyed:    FGAtmosphere" << std::endl;
  }
  if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
  }
  if (debug_lvl & 8 ) { // Runtime state variables
  }
  if (debug_lvl & 16) { // Sanity checking
  }
  if (debug_lvl & 128) { //
  }
  if (debug_lvl & 64) {
    if (from == 0) { // Constructor
    }
  }
}

GetAbsoluteViscosity()

virtual double GetAbsoluteViscosity ( void  ) const

inlinevirtual

Returns the absolute viscosity.

Definition at line 199 of file FGAtmosphere.h.

{return Viscosity;}

GetDensity() [1/2]

double GetDensity ( double  altitude ) const

virtual

Returns the density in slugs/ft^3 at a given altitude in ft.

Reimplemented in FGMSIS, and FGMSIS.

Definition at line 182 of file FGAtmosphere.cpp.

{
  return GetPressure(altitude)/(Reng * GetTemperature(altitude));
}

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GetDensity() [2/2]

virtual double GetDensity ( void  ) const

inlinevirtual

Returns the density in slugs/ft^3.

This function may only be used if Run() is called first.

Reimplemented in FGMSIS.

Definition at line 167 of file FGAtmosphere.h.

{return Density;}

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GetDensityAltitude()

virtual double GetDensityAltitude ( ) const

inlinevirtual

Definition at line 205 of file FGAtmosphere.h.

{return DensityAltitude;}

GetDensityRatio()

virtual double GetDensityRatio ( void  ) const

inlinevirtual

Returns the ratio of at-altitude density over the sea level value.

Definition at line 176 of file FGAtmosphere.h.

{ return Density/SLdensity; }

GetDensitySL()

virtual double GetDensitySL ( void  ) const

inlinevirtual

Returns the sea level density in slugs/ft^3.

Definition at line 173 of file FGAtmosphere.h.

{ return SLdensity; }

GetKinematicViscosity()

virtual double GetKinematicViscosity ( void  ) const

inlinevirtual

Returns the kinematic viscosity.

Definition at line 202 of file FGAtmosphere.h.

{return KinematicViscosity;}

GetPressure() [1/2]

virtual double GetPressure ( double  altitude ) const

pure virtual

Returns the pressure at a specified altitude in psf.

Implemented in FGMSIS, FGStandardAtmosphere, and FGMSIS.

GetPressure() [2/2]

virtual double GetPressure ( void  ) const

inlinevirtual

Returns the pressure in psf.

Reimplemented in FGMSIS.

Definition at line 144 of file FGAtmosphere.h.

{return Pressure;}

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GetPressureAltitude()

virtual double GetPressureAltitude ( ) const

inlinevirtual

Definition at line 207 of file FGAtmosphere.h.

{return PressureAltitude;}

GetPressureRatio()

virtual double GetPressureRatio ( void  ) const

inlinevirtual

Returns the ratio of at-altitude pressure over the sea level value.

Definition at line 153 of file FGAtmosphere.h.

{ return Pressure/SLpressure; }

GetPressureSL()

virtual double GetPressureSL ( ePressure  to = ePSF ) const

inlinevirtual

Definition at line 150 of file FGAtmosphere.h.

{ return ConvertFromPSF(SLpressure, to);  }

GetSoundSpeed() [1/2]

double GetSoundSpeed ( double  altitude ) const

virtual

Returns the speed of sound in ft/sec at a given altitude in ft.

Reimplemented in FGMSIS, and FGMSIS.

Definition at line 189 of file FGAtmosphere.cpp.

{
  return sqrt(SHRatio * Reng * GetTemperature(altitude));
}

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GetSoundSpeed() [2/2]

virtual double GetSoundSpeed ( void  ) const

inlinevirtual

Returns the speed of sound in ft/sec.

Reimplemented in FGMSIS.

Definition at line 183 of file FGAtmosphere.h.

{return Soundspeed;}

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GetSoundSpeedRatio()

virtual double GetSoundSpeedRatio ( void  ) const

inlinevirtual

Returns the ratio of at-altitude sound speed over the sea level value.

Definition at line 192 of file FGAtmosphere.h.

{ return Soundspeed/SLsoundspeed; }

GetSoundSpeedSL()

virtual double GetSoundSpeedSL ( void  ) const

inlinevirtual

Returns the sea level speed of sound in ft/sec.

Definition at line 189 of file FGAtmosphere.h.

{ return SLsoundspeed; }

GetTemperature() [1/2]

virtual double GetTemperature ( ) const

inlinevirtual

Returns the actual, modeled temperature at the current altitude in degrees Rankine.

Returns

Modeled temperature in degrees Rankine.

Reimplemented in FGMSIS.

Definition at line 109 of file FGAtmosphere.h.

{return Temperature;}

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GetTemperature() [2/2]

virtual double GetTemperature ( double  altitude ) const

pure virtual

Returns the actual modeled temperature in degrees Rankine at a specified altitude.

Parameters

altitude

The altitude above sea level (ASL) in feet.

Returns

Modeled temperature in degrees Rankine at the specified altitude.

Implemented in FGMSIS, FGStandardAtmosphere, and FGMSIS.

GetTemperatureRatio() [1/2]

virtual double GetTemperatureRatio ( ) const

inlinevirtual

Returns the ratio of the at-current-altitude temperature as modeled over the sea level value.

Definition at line 122 of file FGAtmosphere.h.

{ return GetTemperature()/SLtemperature; }

GetTemperatureRatio() [2/2]

virtual double GetTemperatureRatio ( double  h ) const

inlinevirtual

Returns the ratio of the temperature as modeled at the supplied altitude over the sea level value.

Definition at line 126 of file FGAtmosphere.h.

{ return GetTemperature(h)/SLtemperature; }

GetTemperatureSL()

virtual double GetTemperatureSL ( ) const

inlinevirtual

Returns the actual, modeled sea level temperature in degrees Rankine.

Returns

The modeled temperature in degrees Rankine at sea level.

Definition at line 118 of file FGAtmosphere.h.

{ return SLtemperature; }

InitModel()

bool InitModel ( void  )

overridevirtual

Reimplemented from FGModelFunctions.

Reimplemented in FGMSIS.

Definition at line 75 of file FGAtmosphere.cpp.

{
  if (!FGModel::InitModel()) return false;
 
  SLtemperature = Temperature = StdDaySLtemperature;
  SLpressure = Pressure = StdDaySLpressure;
  SLdensity = Density = Pressure/(Reng*Temperature);
  SLsoundspeed = Soundspeed = StdDaySLsoundspeed;
  Calculate(0.0);
 
  return true;
}

Run()

bool Run ( bool  Holding )

overridevirtual

Runs the atmosphere forces model; called by the Executive.

Can pass in a value indicating if the executive is directing the simulation to Hold.

Parameters

Holding

if true, the executive has been directed to hold the sim from advancing time. Some models may ignore this flag, such as the Input model, which may need to be active to listen on a socket for the "Resume" command to be given.

Returns

false if no error

Reimplemented from FGModel.

Definition at line 90 of file FGAtmosphere.cpp.

{
  if (FGModel::Run(Holding)) return true;
  if (Holding) return false;
 
  Calculate(in.altitudeASL);
 
  Debug(2);
  return false;
}

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SetPressureSL()

void SetPressureSL ( ePressure  unit, double  pressure  )

virtual

Sets the sea level pressure for modeling.

Parameters

pressure	The pressure in the units specified.
unit	the unit of measure that the specified pressure is supplied in.

Reimplemented in FGStandardAtmosphere.

Definition at line 171 of file FGAtmosphere.cpp.

{
  double press = ConvertToPSF(pressure, unit);
 
  SLpressure = ValidatePressure(press, "Sea Level pressure");
  SLdensity = GetDensity(0.0);
}

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SetTemperature()

virtual void SetTemperature ( double  t, double  h, eTemperature  unit = eFahrenheit  )

pure virtual

Sets the temperature at the supplied altitude.

Parameters

t	The temperature value in the unit provided.
h	The altitude in feet above sea level.
unit	The unit of the temperature.

Implemented in FGStandardAtmosphere.

SetTemperatureSL()

void SetTemperatureSL ( double  t, eTemperature  unit = eFahrenheit  )

virtual

Sets the Sea Level temperature.

Parameters

t	the temperature value in the unit provided.
unit	the unit of the temperature.

Reimplemented in FGStandardAtmosphere.

Definition at line 199 of file FGAtmosphere.cpp.

{
  double temp = ConvertToRankine(t, unit);
 
  SLtemperature = ValidateTemperature(temp, "Sea Level temperature");
  SLdensity = GetDensity(0.0);
  SLsoundspeed = GetSoundSpeed(0.0);
}

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ValidatePressure()

double ValidatePressure ( double  p, const std::string &  msg, bool  quiet = false  ) const

protected

Check that the pressure is within plausible boundaries.

Parameters

msg	Message to display if the pressure is out of boundaries
quiet	Don't display the message if set to true

Definition at line 104 of file FGAtmosphere.cpp.

{
  const double MinPressure = ConvertToPSF(1E-15, ePascals);
  if (p < MinPressure) {
    if (!quiet) {
      cerr << msg << " " << p << " is too low." << endl
           << msg << " is capped to " << MinPressure << endl;
    }
    return MinPressure;
  }
  return p;
}

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ValidateTemperature()

double ValidateTemperature ( double  t, const std::string &  msg, bool  quiet = false  ) const

protected

Check that the temperature is within plausible boundaries.

Parameters

msg	Message to display if the pressure is out of boundaries
quiet	Don't display the message if set to true

Definition at line 122 of file FGAtmosphere.cpp.

{
  // Minimum known temperature in the universe currently
  constexpr double minUniverseTemperature = KelvinToRankine(1.0);
 
  if (t < minUniverseTemperature) {
    if (!quiet) {
      cerr << msg << " " << t << " is too low." << endl
           << msg << " is capped to " << minUniverseTemperature << endl;
    }
    return minUniverseTemperature;
  }
  return t;
}

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Member Data Documentation

Beta

constexpr double Beta = 2.269690E-08

staticconstexprprotected

Definition at line 235 of file FGAtmosphere.h.

Density

double Density = 0.0

protected

Definition at line 228 of file FGAtmosphere.h.

DensityAltitude

double DensityAltitude = 0.0

protected

Definition at line 232 of file FGAtmosphere.h.

g0

constexpr double g0 = 9.80665 / fttom

staticconstexprprotected

Sea-level acceleration of gravity - ft/s^2.

This constant is defined to compute the International Standard Atmosphere. It is by definition the sea level gravity at a latitude of 45deg. This value is fixed whichever gravity model is used by FGInertial.

Definition at line 289 of file FGAtmosphere.h.

KinematicViscosity

double KinematicViscosity = 0.0

protected

Definition at line 237 of file FGAtmosphere.h.

Mair

constexpr double Mair = 28.9645 * kgtoslug / 1000.0

staticconstexprprotected

Mean molecular weight for air - slug/mol.

Definition at line 283 of file FGAtmosphere.h.

Pressure

double Pressure = 0.0

protected

Definition at line 229 of file FGAtmosphere.h.

PressureAltitude

double PressureAltitude = 0.0

protected

Definition at line 231 of file FGAtmosphere.h.

Reng

double Reng = Reng0

protected

Definition at line 294 of file FGAtmosphere.h.

Reng0

constexpr double Reng0 = Rstar / Mair

staticconstexprprotected

Specific gas constant for air - ft*lbf/slug/R.

Definition at line 291 of file FGAtmosphere.h.

Rstar

constexpr double Rstar = 8.31432 * kgtoslug / KelvinToRankine(fttom * fttom)

staticconstexprprotected

Universal gas constant - ft*lbf/R/mol.

Definition at line 281 of file FGAtmosphere.h.

SHRatio

constexpr double SHRatio = 1.4

staticconstexpr

Definition at line 218 of file FGAtmosphere.h.

SLdensity

double SLdensity = 1.0

protected

Definition at line 223 of file FGAtmosphere.h.

SLpressure

double SLpressure = 1.0

protected

Definition at line 224 of file FGAtmosphere.h.

SLsoundspeed

double SLsoundspeed = 1.0

protected

Definition at line 225 of file FGAtmosphere.h.

SLtemperature

double SLtemperature = 1.8

protected

Definition at line 222 of file FGAtmosphere.h.

Soundspeed

double Soundspeed = 0.0

protected

Definition at line 230 of file FGAtmosphere.h.

StdDaySLdensity

constexpr double StdDaySLdensity = StdDaySLpressure / (Reng0 * StdDaySLtemperature)

staticconstexpr

Definition at line 300 of file FGAtmosphere.h.

StdDaySLpressure

constexpr double StdDaySLpressure = 2116.228

staticconstexpr

Definition at line 216 of file FGAtmosphere.h.

StdDaySLsoundspeed

const double StdDaySLsoundspeed

Definition at line 217 of file FGAtmosphere.h.

StdDaySLtemperature

constexpr double StdDaySLtemperature = 518.67

staticconstexpr

Definition at line 215 of file FGAtmosphere.h.

SutherlandConstant

constexpr double SutherlandConstant = 198.72

staticconstexprprotected

Definition at line 234 of file FGAtmosphere.h.

Temperature

double Temperature = 1.8

protected

Definition at line 227 of file FGAtmosphere.h.

Viscosity

double Viscosity = 0.0

protected

Definition at line 236 of file FGAtmosphere.h.

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The documentation for this class was generated from the following files:

• FGAtmosphere.h
• FGAtmosphere.cpp