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.
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 (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...
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	PutMessage (const Message &msg)
	Places a Message structure on the Message queue. More...
void	PutMessage (const std::string &text)
	Creates a message with the given text and places it on the queue. More...
void	PutMessage (const std::string &text, bool bVal)
	Creates a message with the given text and boolean value and places it on the queue. More...
void	PutMessage (const std::string &text, int iVal)
	Creates a message with the given text and integer value and places it on the queue. More...
void	PutMessage (const std::string &text, double dVal)
	Creates a message with the given text and double value and places it on the queue. More...
int	SomeMessages (void) const
	Reads the message on the queue (but does not delete it). More...
void	ProcessMessage (void)
	Reads the message on the queue and removes it from the queue. More...
Message *	ProcessNextMessage (void)
	Reads the next message on the queue and removes it from the queue. More...
void	disableHighLighting (void)
	Disables highlighting in the console output.

Viscosity access functions.
struct JSBSim::FGAtmosphere::Inputs	in
static constexpr double	StdDaySLtemperature = 518.67
static constexpr double	StdDaySLpressure = 2116.228
static const double	StdDaySLsoundspeed = sqrt(SHRatio*Reng*StdDaySLtemperature)
double	SLtemperature
double	SLdensity
double	SLpressure
double	SLsoundspeed
double	Temperature
double	Density
double	Pressure
double	Soundspeed
double	PressureAltitude
double	DensityAltitude
double	Viscosity
double	KinematicViscosity
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.

ISA constants
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 double	Reng = Rstar / Mair
	Specific gas constant for air - ft*lbf/slug/R.
static constexpr double	SHRatio = 1.4
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 double	PitotTotalPressure (double mach, double p)
	Compute the total pressure in front of the Pitot tube. More...
static double	MachFromImpactPressure (double qc, double p)
	Compute the Mach number from the differential pressure (qc) and the static pressure. More...
static double	VcalibratedFromMach (double mach, double p)
	Calculate the calibrated airspeed from the Mach number. More...
static double	MachFromVcalibrated (double vcas, double p)
	Calculate the Mach number from the calibrated airspeed.Based on the formulas in the US Air Force Aircraft Performance Flight Testing Manual (AFFTC-TIH-99-01). 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 double	GaussianRandomNumber (void)
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
FGPropertyManager *	PropertyManager
unsigned int	rate
Protected Attributes inherited from FGModelFunctions
FGPropertyReader	LocalProperties
std::vector< FGFunction * >	PostFunctions
std::vector< FGFunction * >	PreFunctions
Static Protected Attributes inherited from FGJSBBase
static Message	localMsg
static std::queue< Message >	Messages
static unsigned int	messageId = 0
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	ktstofps = 1.68781
static constexpr double	fpstokts = 1.0 / ktstofps
static constexpr double	inchtoft = 1.0/12.0
static constexpr double	fttom = 0.3048
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. 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__
static int	gaussian_random_number_phase = 0

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 236 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 243 of file FGAtmosphere.h.

{ 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.

Definition at line 167 of file FGAtmosphere.h.

{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.

{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.

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; }

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.

Reimplemented in MSIS.

Definition at line 94 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 135 of file FGAtmosphere.cpp.

{
  double press = ConvertToPSF(pressure, unit);
 
  SLpressure = press;
}

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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 162 of file FGAtmosphere.cpp.

{
  SLtemperature = ConvertToRankine(t, unit);
}

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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 268 of file FGAtmosphere.h.

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

• FGAtmosphere.h
• FGAtmosphere.cpp