Encapsulates the aerodynamic calculations. More...

#include <FGAerodynamics.h>

Inheritance diagram for FGAerodynamics:

Collaboration diagram for FGAerodynamics:

Classes
struct	Inputs

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

	~FGAerodynamics ()
	Destructor.

std::vector< FGFunction * > *	GetAeroFunctions (void) const

std::string	GetAeroFunctionStrings (const std::string &delimeter) const
	Gets the strings for the current set of aero functions. More...

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

double	GetAlphaCLMax (void) const

double	GetAlphaCLMin (void) const

double	GetAlphaW (void) const

double	GetBI2Vel (void) const

double	GetCI2Vel (void) const

double	GetClSquared (void) const
	Retrieves the square of the lift coefficient. More...

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

double	GetForces (int n) const
	Gets the aerodynamic force for an axis. More...

double	GetHysteresisParm (void) const

double	GetLoD (void) const
	Retrieves the lift over drag ratio.

const FGColumnVector3 &	GetMoments (void) const
	Gets the total aerodynamic moment vector about the CG. More...

double	GetMoments (int n) const
	Gets the aerodynamic moment about the CG for an axis. More...

const FGColumnVector3 &	GetMomentsMRC (void) const
	Gets the total aerodynamic moment vector about the Moment Reference Center. More...

double	GetMomentsMRC (int n) const
	Gets the aerodynamic moment about the Moment Reference Center for an axis. More...

double	GetStallWarn (void) const

const FGColumnVector3 &	GetvFw (void) const
	Retrieves the aerodynamic forces in the wind axes. More...

double	GetvFw (int axis) const
	Retrieves the aerodynamic forces in the wind axes, given an axis. More...

bool	InitModel (void)

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

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

void	SetAlphaCLMax (double tt)

void	SetAlphaCLMin (double tt)

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
struct JSBSim::FGAerodynamics::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 aerodynamic calculations.

This class owns and contains the list of force/coefficients that define the aerodynamic properties of an aircraft. Here also, such unique phenomena as ground effect, aerodynamic reference point shift, and maximum lift curve tailoff are handled.

<aerodynamics>
   <alphalimits unit="{RAD | DEG}">
     <min> {number} </min>
     <max> {number} </max>
   </alphalimits>
   <hysteresis_limits unit="{RAD | DEG}">
     <min> {number} </min>
     <max> {number} </max>
   </hysteresis_limits>
   <aero_ref_pt_shift_x>  
     <function>
       {function contents}
     </function> 
   </aero_ref_pt_shift_x>  
   <function>
     {function contents}
   </function>
   <axis name="{LIFT | DRAG | SIDE | ROLL | PITCH | YAW}">
     {force or moment definitions}
   </axis>
   {additional axis definitions}
</aerodynamics>

Optionally two other coordinate systems may be used.

1) Body coordinate system:

2) Axial-Normal coordinate system:

Systems may NOT be combined, or a load error will occur.

Author: Jon S. Berndt, Tony Peden

Version

Revision: 1.30

Definition at line 118 of file FGAerodynamics.h.

Constructor & Destructor Documentation

◆ FGAerodynamics()

FGAerodynamics ( FGFDMExec * Executive )

Constructor.

Parameters

Executive a pointer to the parent executive object

Definition at line 61 of file FGAerodynamics.cpp.

                                                  : FGModel(FDMExec)
 {
   Name = "FGAerodynamics";
 
   AxisIdx["DRAG"]   = 0;
   AxisIdx["SIDE"]   = 1;
   AxisIdx["LIFT"]   = 2;
   AxisIdx["ROLL"]   = 3;
   AxisIdx["PITCH"]  = 4;
   AxisIdx["YAW"]    = 5;
 
   AxisIdx["AXIAL"]  = 0;
   AxisIdx["NORMAL"] = 2;
 
   AxisIdx["X"] = 0;
   AxisIdx["Y"] = 1;
   AxisIdx["Z"] = 2;
 
   axisType = atNone;
 
   AeroFunctions = new AeroFunctionArray[6];
   AeroFunctionsAtCG = new AeroFunctionArray[6];
 
   impending_stall = stall_hyst = 0.0;
   alphaclmin = alphaclmax = 0.0;
   alphaclmin0 = alphaclmax0 = 0.0;
   alphahystmin = alphahystmax = 0.0;
   clsq = lod = 0.0;
   alphaw = 0.0;
   bi2vel = ci2vel = 0.0;
   AeroRPShift = 0;
   vDeltaRP.InitMatrix();
 
   bind();
 
   Debug(0);
 }

Member Function Documentation

◆ GetAeroFunctionStrings()

string GetAeroFunctionStrings ( const std::string & delimeter ) const

Gets the strings for the current set of aero functions.

Parameters

delimeter either a tab or comma string depending on output type

Returns: a string containing the descriptive names for all aero functions

Definition at line 436 of file FGAerodynamics.cpp.

 {
   string AeroFunctionStrings = "";
   bool firstime = true;
   unsigned int axis, sd;
 
   for (axis = 0; axis < 6; axis++) {
     for (sd = 0; sd < AeroFunctions[axis].size(); sd++) {
       if (firstime) {
         firstime = false;
       } else {
         AeroFunctionStrings += delimeter;
       }
       AeroFunctionStrings += AeroFunctions[axis][sd]->GetName();
     }
   }
 
   string FunctionStrings = FGModelFunctions::GetFunctionStrings(delimeter);
 
   if (FunctionStrings.size() > 0) {
     if (AeroFunctionStrings.size() > 0) {
       AeroFunctionStrings += delimeter + FunctionStrings;
     } else {
       AeroFunctionStrings = FunctionStrings;
     }
   }
 
   return AeroFunctionStrings;
 }

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◆ GetAeroFunctionValues()

string GetAeroFunctionValues ( const std::string & delimeter ) const

Gets the aero function 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 aero functions

Definition at line 468 of file FGAerodynamics.cpp.

 {
   ostringstream buf;
 
   for (unsigned int axis = 0; axis < 6; axis++) {
     for (unsigned int sd = 0; sd < AeroFunctions[axis].size(); sd++) {
       if (buf.tellp() > 0) buf << delimeter;
       buf << AeroFunctions[axis][sd]->GetValue();
     }
   }
 
   string FunctionValues = FGModelFunctions::GetFunctionValues(delimeter);
 
   if (FunctionValues.size() > 0) {
     if (buf.str().size() > 0) {
       buf << delimeter << FunctionValues;
     } else {
       buf << FunctionValues;
     }
   }
 
   return buf.str();
 }

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◆ GetClSquared()

double GetClSquared ( void ) const

inline

Retrieves the square of the lift coefficient.

Definition at line 188 of file FGAerodynamics.h.

188 { return clsq; }

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◆ GetForces() [1/2]

const FGColumnVector3& GetForces ( void ) const

inline

Gets the total aerodynamic force vector.

Returns: a force vector reference.

Definition at line 148 of file FGAerodynamics.h.

148 {return vForces;}

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◆ GetForces() [2/2]

double GetForces ( int n ) const

inline

Gets the aerodynamic force for an axis.

Parameters

n	Axis index. This could be 0, 1, or 2, or one of the axis enums: eX, eY, eZ.

Returns: the force acting on an axis

Definition at line 154 of file FGAerodynamics.h.

154 {return vForces(n);}

◆ GetMoments() [1/2]

const FGColumnVector3& GetMoments ( void ) const

inline

Gets the total aerodynamic moment vector about the CG.

Returns: a moment vector reference.

Definition at line 158 of file FGAerodynamics.h.

158 {return vMoments;}

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◆ GetMoments() [2/2]

double GetMoments ( int n ) const

inline

Gets the aerodynamic moment about the CG for an axis.

Returns: the moment about a single axis (as described also in the similar call to GetForces(int n).

Definition at line 163 of file FGAerodynamics.h.

163 {return vMoments(n);}

◆ GetMomentsMRC() [1/2]

const FGColumnVector3& GetMomentsMRC ( void ) const

inline

Gets the total aerodynamic moment vector about the Moment Reference Center.

Returns: a moment vector reference.

Definition at line 167 of file FGAerodynamics.h.

167 {return vMomentsMRC;}

◆ GetMomentsMRC() [2/2]

double GetMomentsMRC ( int n ) const

inline

Gets the aerodynamic moment about the Moment Reference Center for an axis.

Returns: the moment about a single axis (as described also in the similar call to GetForces(int n).

Definition at line 172 of file FGAerodynamics.h.

172 {return vMomentsMRC(n);}

◆ GetvFw() [1/2]

const FGColumnVector3& GetvFw ( void ) const

inline

Retrieves the aerodynamic forces in the wind axes.

Returns: a reference to a column vector containing the wind axis forces.

Definition at line 176 of file FGAerodynamics.h.

176 { return vFw; }

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◆ GetvFw() [2/2]

double GetvFw ( int axis ) const

inline

Retrieves the aerodynamic forces in the wind axes, given an axis.

Parameters

axis	the axis to return the force for (eX, eY, eZ).

Returns: a reference to a column vector containing the requested wind axis force.

Definition at line 182 of file FGAerodynamics.h.

182 { return vFw(axis); }

◆ Load()

bool Load ( Element * element )

virtual

Loads the Aerodynamics model.

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

Parameters

element pointer to the current XML element for aerodynamics parameters.

Returns: true if successful

Reimplemented from FGModel.

Definition at line 303 of file FGAerodynamics.cpp.

 {
   string axis;
   string scratch_unit="";
   Element *temp_element, *axis_element, *function_element;
 
   Name = "Aerodynamics Model: " + document->GetAttributeValue("name");
 
   // Perform base class Pre-Load
   if (!FGModel::Load(document))
     return false;
 
   DetermineAxisSystem(document); // Determine if Lift/Side/Drag, etc. is used.
 
   Debug(2);
 
   if ((temp_element = document->FindElement("alphalimits"))) {
     scratch_unit = temp_element->GetAttributeValue("unit");
     if (scratch_unit.empty()) scratch_unit = "RAD";
     alphaclmin0 = temp_element->FindElementValueAsNumberConvertFromTo("min", scratch_unit, "RAD");
     alphaclmax0 = temp_element->FindElementValueAsNumberConvertFromTo("max", scratch_unit, "RAD");
     alphaclmin = alphaclmin0;
     alphaclmax = alphaclmax0;
   }
 
   if ((temp_element = document->FindElement("hysteresis_limits"))) {
     scratch_unit = temp_element->GetAttributeValue("unit");
     if (scratch_unit.empty()) scratch_unit = "RAD";
     alphahystmin = temp_element->FindElementValueAsNumberConvertFromTo("min", scratch_unit, "RAD");
     alphahystmax = temp_element->FindElementValueAsNumberConvertFromTo("max", scratch_unit, "RAD");
   }
 
   if ((temp_element = document->FindElement("aero_ref_pt_shift_x"))) {
     function_element = temp_element->FindElement("function");
     AeroRPShift = new FGFunction(PropertyManager, function_element);
   }
 
   axis_element = document->FindElement("axis");
   while (axis_element) {
     AeroFunctionArray ca;
     AeroFunctionArray ca_atCG;
     axis = axis_element->GetAttributeValue("name");
     function_element = axis_element->FindElement("function");
     while (function_element) {
       string current_func_name = function_element->GetAttributeValue("name");
       bool apply_at_cg = false;
       if (function_element->HasAttribute("apply_at_cg")) {
         if (function_element->GetAttributeValue("apply_at_cg") == "true") apply_at_cg = true;
       }
       if (!apply_at_cg) {
       try {
         ca.push_back( new FGFunction(PropertyManager, function_element) );
       } catch (const string& str) {
         cerr << endl << fgred << "Error loading aerodynamic function in " 
              << current_func_name << ":" << str << " Aborting." << reset << endl;
         return false;
       }
       } else {
         try {
           ca_atCG.push_back( new FGFunction(PropertyManager, function_element) );
         } catch (const string& str) {
           cerr << endl << fgred << "Error loading aerodynamic function in " 
                << current_func_name << ":" << str << " Aborting." << reset << endl;
           return false;
         }
       }
       function_element = axis_element->FindNextElement("function");
     }
     AeroFunctions[AxisIdx[axis]] = ca;
     AeroFunctionsAtCG[AxisIdx[axis]] = ca_atCG;
     axis_element = document->FindNextElement("axis");
   }
 
   PostLoad(document, PropertyManager); // Perform base class Post-Load
 
   return true;
 }

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◆ Run()

bool Run ( bool Holding )

virtual

Runs the Aerodynamics 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 141 of file FGAerodynamics.cpp.

 {
 
   if (FGModel::Run(Holding)) return true;
   if (Holding) return false; // if paused don't execute
 
   unsigned int axis_ctr;
   const double twovel=2*in.Vt;
 
   // The lift coefficient squared (property aero/cl-squared) is computed before
   // the aero functions are called to make sure that they use the same value for
   // qbar.
   if ( in.Qbar > 1.0) {
     // Skip the computation if qbar is close to zero to avoid huge values for
     // aero/cl-squared when a non-null lift coincides with a very small aero
     // velocity (i.e. when qbar is close to zero).
     clsq = (vFw(eLift) + vFwAtCG(eLift))/ (in.Wingarea*in.Qbar);
     clsq *= clsq;
   }
 
   RunPreFunctions();
 
   // calculate some oft-used quantities for speed
 
   if (twovel != 0) {
     bi2vel = in.Wingspan / twovel;
     ci2vel = in.Wingchord / twovel;
   }
   alphaw = in.Alpha + in.Wingincidence;
   qbar_area = in.Wingarea * in.Qbar;
 
   if (alphaclmax != 0) {
     if (in.Alpha > 0.85*alphaclmax) {
       impending_stall = 10*(in.Alpha/alphaclmax - 0.85);
     } else {
       impending_stall = 0;
     }
   }
 
   if (alphahystmax != 0.0 && alphahystmin != 0.0) {
     if (in.Alpha > alphahystmax) {
        stall_hyst = 1;
     } else if (in.Alpha < alphahystmin) {
        stall_hyst = 0;
     }
   }
 
   vFw.InitMatrix();
   vFwAtCG.InitMatrix();
   vFnative.InitMatrix();
   vFnativeAtCG.InitMatrix();
 
   for (axis_ctr = 0; axis_ctr < 3; ++axis_ctr) {
     AeroFunctionArray::iterator f;
 
     AeroFunctionArray* array = &AeroFunctions[axis_ctr];
     for (f=array->begin(); f != array->end(); ++f) {
       // Tell the Functions to cache values, so when the function values are
       // being requested for output, the functions do not get calculated again
       // in a context that might have changed, but instead use the values that
       // have already been calculated for this frame.
       (*f)->cacheValue(true);
       vFnative(axis_ctr+1) += (*f)->GetValue();
     }
 
     array = &AeroFunctionsAtCG[axis_ctr];
     for (f=array->begin(); f != array->end(); ++f) {
       (*f)->cacheValue(true); // Same as above
       vFnativeAtCG(axis_ctr+1) += (*f)->GetValue();
     }
   }
 
   // Note that we still need to convert to wind axes here, because it is
   // used in the L/D calculation, and we still may want to look at Lift
   // and Drag.
 
   // JSB 4/27/12 - After use, convert wind axes to produce normal lift
   // and drag values - not negative ones!
 
   // As a clarification, JSBSim assumes that drag and lift values are defined 
   // in wind axes - BUT with a 180 rotation about the Y axis. That is, lift and
   // drag will be positive up and aft, respectively, so that they are reported
   // as positive numbers. However, the wind axes themselves assume that the X
   // and Z forces are positive forward and down.
 
   switch (axisType) {
     case atBodyXYZ:       // Forces already in body axes; no manipulation needed
       vFw = in.Tb2w*vFnative;
       vForces = vFnative;
       vFw(eDrag)*=-1; vFw(eLift)*=-1;
 
       vFwAtCG = in.Tb2w*vFnativeAtCG;
       vForcesAtCG = vFnativeAtCG;
       vFwAtCG(eDrag)*=-1; vFwAtCG(eLift)*=-1;
       break;
     case atLiftDrag:      // Copy forces into wind axes
       vFw = vFnative;
       vFw(eDrag)*=-1; vFw(eLift)*=-1;
       vForces = in.Tw2b*vFw;
       vFw(eDrag)*=-1; vFw(eLift)*=-1;
 
       vFwAtCG = vFnativeAtCG;
       vFwAtCG(eDrag)*=-1; vFwAtCG(eLift)*=-1;
       vForcesAtCG = in.Tw2b*vFwAtCG;
       vFwAtCG(eDrag)*=-1; vFwAtCG(eLift)*=-1;
       break;
     case atAxialNormal:   // Convert native forces into Axial|Normal|Side system
       vFw = in.Tb2w*vFnative;
       vFnative(eX)*=-1; vFnative(eZ)*=-1;
       vForces = vFnative;
 
       vFwAtCG = in.Tb2w*vFnativeAtCG;
       vFnativeAtCG(eX)*=-1; vFnativeAtCG(eZ)*=-1;
       vForcesAtCG = vFnativeAtCG;
       break;
     default:
       cerr << endl << "  A proper axis type has NOT been selected. Check "
                    << "your aerodynamics definition." << endl;
       exit(-1);
   }
 
   // Calculate lift Lift over Drag
   if ( fabs(vFw(eDrag) + vFwAtCG(eDrag)) > 0.0)
     lod = fabs( (vFw(eLift) + vFwAtCG(eLift))/ (vFw(eDrag) + vFwAtCG(eDrag)));
 
   // Calculate aerodynamic reference point shift, if any. The shift
   // takes place in the structual axis. That is, if the shift is positive,
   // it is towards the back (tail) of the vehicle. The AeroRPShift
   // function should be non-dimensionalized by the wing chord. The
   // calculated vDeltaRP will be in feet.
   if (AeroRPShift) vDeltaRP(eX) = AeroRPShift->GetValue()*in.Wingchord;
 
   vDXYZcg(eX) = in.RPBody(eX) - vDeltaRP(eX); // vDeltaRP is given in the structural frame
   vDXYZcg(eY) = in.RPBody(eY) + vDeltaRP(eY);
   vDXYZcg(eZ) = in.RPBody(eZ) - vDeltaRP(eZ);
 
   vMomentsMRC.InitMatrix();
 
   for (axis_ctr = 0; axis_ctr < 3; axis_ctr++) {
     AeroFunctionArray* array = &AeroFunctions[axis_ctr+3];
     for (AeroFunctionArray::iterator f=array->begin(); f != array->end(); ++f) {
       // Tell the Functions to cache values, so when the function values are
       // being requested for output, the functions do not get calculated again
       // in a context that might have changed, but instead use the values that
       // have already been calculated for this frame.
       (*f)->cacheValue(true);
       vMomentsMRC(axis_ctr+1) += (*f)->GetValue();
     }
   }
   vMoments = vMomentsMRC + vDXYZcg*vForces; // M = r X F
   // Now add the "at CG" values to base forces - after the moments have been transferred
   vForces += vForcesAtCG;
   vFnative += vFnativeAtCG;
   vFw += vFwAtCG;
 
   RunPostFunctions();
 
   return false;
 }

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

Classes

Public Member Functions

Public Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ FGAerodynamics()

Member Function Documentation

◆ GetAeroFunctionStrings()

◆ GetAeroFunctionValues()

◆ GetClSquared()

◆ GetForces() [1/2]

◆ GetForces() [2/2]

◆ GetMoments() [1/2]

◆ GetMoments() [2/2]

◆ GetMomentsMRC() [1/2]

◆ GetMomentsMRC() [2/2]

◆ GetvFw() [1/2]

◆ GetvFw() [2/2]

◆ Load()

◆ Run()