Encapsulates the Buoyant forces calculations. More...

#include <FGBuoyantForces.h>

Inheritance diagram for FGBuoyantForces:

Collaboration diagram for FGBuoyantForces:

Public Member Functions
	FGBuoyantForces (FGFDMExec *Executive)
	Constructor. More...

	~FGBuoyantForces ()
	Destructor.

std::string	GetBuoyancyStrings (const std::string &delimeter)
	Gets the strings for the current set of gas cells. More...

std::string	GetBuoyancyValues (const std::string &delimeter)
	Gets the coefficient values. More...

const FGColumnVector3 &	GetForces (void) const
	Gets the total Buoyant force vector. More...

double	GetForces (int idx) const
	Gets a component of the total Buoyant force vector. More...

double	GetGasMass (void) const
	Gets the total gas mass. More...

const FGMatrix33 &	GetGasMassInertia (void)
	Gets the total moments of inertia for the gas mass in the body frame. More...

const FGColumnVector3 &	GetGasMassMoment (void)
	Gets the total moment from the gas mass. More...

const FGColumnVector3 &	GetMoments (void) const
	Gets the total Buoyancy moment vector. More...

double	GetMoments (int idx) const
	Gets a component of the total Buoyancy moment vector. More...

bool	InitModel (void)

bool	Load (Element *element)
	Loads the Buoyant forces model. More...

bool	Run (bool Holding)
	Runs the Buoyant forces model; called by the Executive Can pass in a value indicating if the executive is directing the simulation to Hold. More...

Public Member Functions inherited from FGModel
	FGModel (FGFDMExec *)
	Constructor.

virtual	~FGModel ()
	Destructor.

virtual SGPath	FindFullPathName (const SGPath &path) const

FGFDMExec *	GetExec (void)

unsigned int	GetRate (void)
	Get the output rate for the model in frames.

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, FGPropertyManager PropertyManager, std::string prefix="")

void	PostLoad (Element el, FGPropertyManager PropertyManager, std::string prefix="")

void	PreLoad (Element el, FGPropertyManager PropertyManager, 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.

std::string	GetVersion (void)
	Returns the version number of JSBSim. More...

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)
	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...

Public Attributes
FGGasCell::Inputs	in

Public Attributes inherited from FGModel
std::string	Name

Additional Inherited Members
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.

Static Public Member Functions inherited from FGJSBBase
static double	CelsiusToFahrenheit (double celsius)
	Converts from degrees Celsius to degrees Fahrenheit. More...

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

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

static double	Constrain (double min, double value, double max)
	Constrain a value between a minimum and a maximum value.

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

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

static double	GaussianRandomNumber (void)

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

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

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

static double	MachFromVcalibrated (double vcas, double p, double psl, double rhosl)
	Calculate the Mach number from the calibrated airspeed. More...

static double	PitotTotalPressure (double mach, double p)
	Compute the total pressure in front of the Pitot tube. More...

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

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

static double	sign (double num)

static double	VcalibratedFromMach (double mach, double p, double psl, double rhosl)
	Calculate the calibrated airspeed from the Mach number. More...

Static Public Attributes inherited from FGJSBBase
static short	debug_lvl = 1

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

Protected Member Functions inherited from FGJSBBase
void	Debug (int)

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

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 const double	degtorad = 0.017453292519943295769236907684886

static const double	fpstokts = 1.0/ktstofps

static const double	fttom = 0.3048

static int	gaussian_random_number_phase = 0

static const double	hptoftlbssec = 550.0

static const double	in3tom3 = 1.638706E-5

static const double	inchtoft = 0.08333333

static const double	inhgtopa = 3386.38

static const std::string	JSBSim_version = "1.0 " __DATE__ " " __TIME__

static const double	kgtolb = 2.20462

static const double	kgtoslug = 0.06852168

static const double	ktstofps = 1.68781

static const double	lbtoslug = 1.0/slugtolb

static Message	localMsg

static const double	m3toft3 = 1.0/(fttomfttomfttom)

static double	Mair = 28.9645

static unsigned int	messageId = 0

static std::queue< Message >	Messages

static const std::string	needed_cfg_version = "2.0"

static const double	psftoinhg = 0.014138

static const double	psftopa = 47.88

static const double	radtodeg = 57.295779513082320876798154814105

static double	Reng = 1716.56

static double	Rstar = 1545.348

static const double	SHRatio = 1.40

static const double	slugtolb = 32.174049

Detailed Description

Encapsulates the Buoyant forces calculations.

This class owns and contains the list of force/coefficients that define the Buoyant properties of an air vehicle.

Here's an example of a gas cell specification:

<buoyant_forces>
  <!-- Interface properties -->
  <property>ballonets/in-flow-ft3ps[0]</property>
  <gas_cell type="HYDROGEN">
    <location unit="M">
      <x> 18.8 </x>
      <y> 0.0 </y>
      <z> 0.0 </z>
    </location>
    <x_radius unit="M"> 22.86 </x_radius>
    <y_radius unit="M">  4.55 </y_radius>
    <z_radius unit="M">  4.55 </z_radius>
    <max_overpressure unit="PA"> 340.0 </max_overpressure> 
    <valve_coefficient unit="M4*SEC/KG"> 0.015 </valve_coefficient>
  </gas_cell>
  
  ... {other gas cells} ...
  
</buoyant_forces>

See FGGasCell for the full configuration file format for gas cells.

Author: Anders Gidenstam, Jon S. Berndt

Version

Id: FGBuoyantForces.h,v 1.18 2013/11/24 11:40:55 bcoconni Exp

Definition at line 105 of file FGBuoyantForces.h.

Constructor & Destructor Documentation

◆ FGBuoyantForces()

FGBuoyantForces ( FGFDMExec * Executive )

Constructor.

Parameters

Executive a pointer to the parent executive object

Definition at line 57 of file FGBuoyantForces.cpp.

                                                    : FGModel(FDMExec)
 {
   Name = "FGBuoyantForces";
 
   NoneDefined = true;
 
   vTotalForces.InitMatrix();
   vTotalMoments.InitMatrix();
 
   gasCellJ.InitMatrix();
 
   Debug(0);
 }

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Member Function Documentation

◆ GetBuoyancyStrings()

string GetBuoyancyStrings ( const std::string & delimeter )

Gets the strings for the current set of gas cells.

Parameters

delimeter either a tab or comma string depending on output type

Returns: a string containing the descriptive names for all parameters

Definition at line 188 of file FGBuoyantForces.cpp.

 {
   string CoeffStrings = "";
 /*
   bool firstime = true;
   for (sd = 0; sd < variables.size(); sd++) {
     if (firstime) {
       firstime = false;
     } else {
       CoeffStrings += delimeter;
     }
     CoeffStrings += variables[sd]->GetName();
   }
 
   for (axis = 0; axis < 6; axis++) {
     for (sd = 0; sd < AeroFunctions[axis].size(); sd++) {
       if (firstime) {
         firstime = false;
       } else {
         CoeffStrings += delimeter;
       }
       CoeffStrings += AeroFunctions[axis][sd]->GetName();
     }
   }
 */
   return CoeffStrings;
 }

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◆ GetBuoyancyValues()

string GetBuoyancyValues ( const std::string & delimeter )

Gets the coefficient values.

Parameters

delimeter either a tab or comma string depending on output type

Returns: a string containing the numeric values for the current set of parameters

Definition at line 218 of file FGBuoyantForces.cpp.

 {
   string SDValues = "";
 /*
   bool firstime = true;
   for (sd = 0; sd < variables.size(); sd++) {
     if (firstime) {
       firstime = false;
     } else {
       SDValues += delimeter;
     }
     SDValues += variables[sd]->GetValueAsString();
   }
 
   for (unsigned int axis = 0; axis < 6; axis++) {
     for (unsigned int sd = 0; sd < AeroFunctions[axis].size(); sd++) {
       if (firstime) {
         firstime = false;
       } else {
         SDValues += delimeter;
       }
       SDValues += AeroFunctions[axis][sd]->GetValueAsString();
     }
   }
 */
   return SDValues;
 }

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◆ GetForces() [1/2]

const FGColumnVector3& GetForces ( void ) const

inline

Gets the total Buoyant force vector.

Returns: a force vector in lbs.

Definition at line 135 of file FGBuoyantForces.h.

135 {return vTotalForces;}

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◆ GetForces() [2/2]

double GetForces ( int idx ) const

inline

Gets a component of the total Buoyant force vector.

Returns: a component of the force vector in lbs.

Definition at line 139 of file FGBuoyantForces.h.

139 {return vTotalForces(idx);}

◆ GetGasMass()

double GetGasMass ( void ) const

Gets the total gas mass.

The gas mass is part of the aircraft's inertia.

Returns: mass in slugs.

Definition at line 147 of file FGBuoyantForces.cpp.

 {
   double Gw = 0.0;
 
   for (unsigned int i = 0; i < Cells.size(); i++) {
     Gw += Cells[i]->GetMass();
   }
 
   return Gw;
 }

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◆ GetGasMassInertia()

const FGMatrix33 & GetGasMassInertia ( void )

Gets the total moments of inertia for the gas mass in the body frame.

Returns: moments of inertia matrix in the body frame in slug ft².

Definition at line 171 of file FGBuoyantForces.cpp.

 {
   size_t size = Cells.size();
   
   if (size == 0) return gasCellJ;
 
   gasCellJ = FGMatrix33();
 
   for (unsigned int i=0; i < size; i++) {
     gasCellJ += Cells[i]->GetInertia();
   }
   
   return gasCellJ;
 }

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◆ GetGasMassMoment()

const FGColumnVector3 & GetGasMassMoment ( void )

Gets the total moment from the gas mass.

Returns: a moment vector in the structural frame in lbs in.

Definition at line 160 of file FGBuoyantForces.cpp.

 {
   vXYZgasCell_arm.InitMatrix();
   for (unsigned int i = 0; i < Cells.size(); i++) {
     vXYZgasCell_arm += Cells[i]->GetMassMoment();
   }
   return vXYZgasCell_arm;
 }

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◆ GetMoments() [1/2]

const FGColumnVector3& GetMoments ( void ) const

inline

Gets the total Buoyancy moment vector.

Returns: a moment vector in the body frame in lbs ft.

Definition at line 143 of file FGBuoyantForces.h.

143 {return vTotalMoments;}

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◆ GetMoments() [2/2]

double GetMoments ( int idx ) const

inline

Gets a component of the total Buoyancy moment vector.

Returns: a component of the moment vector in the body frame in lbs ft.

Definition at line 147 of file FGBuoyantForces.h.

147 {return vTotalMoments(idx);}

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◆ Load()

bool Load ( Element * element )

virtual

Loads the Buoyant forces model.

The Load function for this class expects the XML parser to have found the Buoyant_forces keyword in the configuration file.

Parameters

element pointer to the current XML element for Buoyant forces parameters.

Returns: true if successful

Reimplemented from FGModel.

Definition at line 119 of file FGBuoyantForces.cpp.

 {
   Element *gas_cell_element;
 
   Debug(2);
 
   // Perform base class Pre-Load
   if (!FGModel::Load(document))
     return false;
 
   gas_cell_element = document->FindElement("gas_cell");
   while (gas_cell_element) {
     NoneDefined = false;
     Cells.push_back(new FGGasCell(FDMExec, gas_cell_element, Cells.size(), in));
     gas_cell_element = document->FindNextElement("gas_cell");
   }
   
   PostLoad(document, PropertyManager);
 
   if (!NoneDefined) {
     bind();
   }
 
   return true;
 }

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◆ Run()

bool Run ( bool Holding )

virtual

Runs the Buoyant 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 95 of file FGBuoyantForces.cpp.

 {
   if (FGModel::Run(Holding)) return true;
   if (Holding) return false; // if paused don't execute
   if (NoneDefined) return true;
 
   RunPreFunctions();
 
   vTotalForces.InitMatrix();
   vTotalMoments.InitMatrix();
 
   for (unsigned int i=0; i<Cells.size(); i++) {
     Cells[i]->Calculate(FDMExec->GetDeltaT());
     vTotalForces  += Cells[i]->GetBodyForces();
     vTotalMoments += Cells[i]->GetMoments();
   }
 
   RunPostFunctions();
 
   return false;
 }

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

Public Member Functions

Public Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ FGBuoyantForces()

Member Function Documentation

◆ GetBuoyancyStrings()

◆ GetBuoyancyValues()

◆ GetForces() [1/2]

◆ GetForces() [2/2]

◆ GetGasMass()

◆ GetGasMassInertia()

◆ GetGasMassMoment()

◆ GetMoments() [1/2]

◆ GetMoments() [2/2]

◆ Load()

◆ Run()