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.

enum	eTemperature { eNoTempUnit =0 , eFahrenheit , eCelsius , eRankine , eKelvin }
	Enums for specifying temperature units.

Public Types inherited from FGJSBBase
enum	{ eL = 1 , eM , eN }
	Moments L, M, N.

enum	{ eP = 1 , eQ , eR }
	Rates P, Q, R.

enum	{ eU = 1 , eV , eW }
	Velocities U, V, W.

enum	{ eX = 1 , eY , eZ }
	Positions X, Y, Z.

enum	{ ePhi = 1 , eTht , ePsi }
	Euler angles Phi, Theta, Psi.

enum	{ eDrag = 1 , eSide , eLift }
	Stability axis forces, Drag, Side force, Lift.

enum	{ eRoll = 1 , ePitch , eYaw }
	Local frame orientation Roll, Pitch, Yaw.

enum	{ eNorth = 1 , eEast , eDown }
	Local frame position North, East, Down.

enum	{ eLat = 1 , eLong , eRad }
	Locations Radius, Latitude, Longitude.

enum	{ inNone = 0 , inDegrees , inRadians , inMeters , inFeet }
	Conversion specifiers.

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. More...

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. More...

virtual double	GetTemperature (double altitude) const =0
	Returns the actual modeled temperature in degrees Rankine at a specified altitude. More...

virtual double	GetTemperatureSL () const
	Returns the actual, modeled sea level temperature in degrees Rankine. More...

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. More...

virtual void	SetTemperature (double t, double h, eTemperature unit=eFahrenheit)=0
	Sets the temperature at the supplied altitude. More...

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. More...

Density access functions.
virtual double	GetDensity (void) const
	Returns the density in slugs/ft^3. More...

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. More...

std::string	GetFunctionValues (const std::string &delimeter) const
	Gets the function values. More...

std::shared_ptr< FGFunction >	GetPreFunction (const std::string &name)
	Get one of the "pre" function. More...

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. More...

virtual double	CalculatePressureAltitude (double pressure, double geometricAlt)
	Calculates the pressure altitude given any temperature or pressure bias. More...

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 string &msg, bool quiet=false) const
	Check that the pressure is within plausible boundaries. More...

double	ValidateTemperature (double t, const string &msg, bool quiet=false) const
	Check that the temperature is within plausible boundaries. More...

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. More...

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. More...

static constexpr double	KelvinToFahrenheit (double kelvin)
	Converts from degrees Kelvin to degrees Fahrenheit. More...

static constexpr double	CelsiusToRankine (double celsius)
	Converts from degrees Celsius to degrees Rankine. More...

static constexpr double	RankineToCelsius (double rankine)
	Converts from degrees Rankine to degrees Celsius. More...

static constexpr double	KelvinToRankine (double kelvin)
	Converts from degrees Kelvin to degrees Rankine. More...

static constexpr double	RankineToKelvin (double rankine)
	Converts from degrees Rankine to degrees Kelvin. More...

static constexpr double	FahrenheitToCelsius (double fahrenheit)
	Converts from degrees Fahrenheit to degrees Celsius. More...

static constexpr double	CelsiusToFahrenheit (double celsius)
	Converts from degrees Celsius to degrees Fahrenheit. More...

static constexpr double	CelsiusToKelvin (double celsius)
	Converts from degrees Celsius to degrees Kelvin. More...

static constexpr double	KelvinToCelsius (double kelvin)
	Converts from degrees Kelvin to degrees Celsius. More...

static constexpr double	FeetToMeters (double measure)
	Converts from feet to meters. More...

static bool	EqualToRoundoff (double a, double b)
	Finite precision comparison. More...

static bool	EqualToRoundoff (float a, float b)
	Finite precision comparison. More...

static bool	EqualToRoundoff (float a, double b)
	Finite precision comparison. More...

static bool	EqualToRoundoff (double a, float b)
	Finite precision comparison. More...

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. More...

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/(fttomfttomfttom)

static constexpr double	in3tom3 = inchtoftinchtoftinchtoft/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. More...

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 Function Documentation

◆ 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.

247 { 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.

254 { return geometricAlt; }

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◆ GetDensity()

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, and FGMSIS.

Definition at line 167 of file FGAtmosphere.h.

167 {return Density;}

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◆ 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.

Definition at line 109 of file FGAtmosphere.h.

109 {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 FGStandardAtmosphere, and FGMSIS.

◆ 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.

118 { return SLtemperature; }

◆ 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 88 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 169 of file FGAtmosphere.cpp.

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

◆ 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 197 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 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 102 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 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 120 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

◆ 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.

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

Detailed Description

Properties

Classes

Public Types

Public Member Functions

Viscosity access functions.

ISA constants

Additional Inherited Members

Member Function Documentation

◆ CalculateDensityAltitude()

◆ CalculatePressureAltitude()

◆ GetDensity()

◆ GetTemperature() [1/2]

◆ GetTemperature() [2/2]

◆ GetTemperatureSL()

◆ Run()

◆ SetPressureSL()

◆ SetTemperature()

◆ SetTemperatureSL()

◆ ValidatePressure()

◆ ValidateTemperature()

Member Data Documentation

◆ g0