Implementation of 1959 Standard Atmosphere added by Tony Peden
Date started: 11/24/98
- ------------- Copyright (C) 1999 Jon S. Berndt (jsb@hal-pc.org) -------------
+ ------------- Copyright (C) 1999 Jon S. Berndt (jon@jsbsim.org) -------------
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the Free Software
SENTRY
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-#ifndef FGAtmosphere_H
-#define FGAtmosphere_H
+#ifndef FGATMOSPHERE_H
+#define FGATMOSPHERE_H
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
INCLUDES
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
#include "FGModel.h"
-#include <math/FGColumnVector3.h>
+#include "math/FGColumnVector3.h"
+#include "math/FGTable.h"
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
DEFINITIONS
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-#define ID_ATMOSPHERE "$Id$"
+#define ID_ATMOSPHERE "$Id: FGAtmosphere.h,v 1.24 2010/11/18 12:38:06 jberndt Exp $"
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
FORWARD DECLARATIONS
/** Models the 1976 Standard Atmosphere.
@author Tony Peden, Jon Berndt
- @version $Id$
+ @version $Id: FGAtmosphere.h,v 1.24 2010/11/18 12:38:06 jberndt Exp $
@see Anderson, John D. "Introduction to Flight, Third Edition", McGraw-Hill,
1989, ISBN 0-07-001641-0
+
+ Additionally, various turbulence models are available. They are specified
+ via the property <tt>atmosphere/turb-type</tt>. The following models are
+ available:
+ - 0: ttNone (turbulence disabled)
+ - 1: ttStandard
+ - 2: ttBerndt
+ - 3: ttCulp
+ - 4: ttMilspec (Dryden spectrum)
+ - 5: ttTustin (Dryden spectrum)
+
+ The Milspec and Tustin models are described in the Yeager report cited below.
+ They both use a Dryden spectrum model whose parameters (scale lengths and intensities)
+ are modelled according to MIL-F-8785C. Parameters are modelled differently
+ for altitudes below 1000ft and above 2000ft, for altitudes in between they
+ are interpolated linearly.
+
+ The two models differ in the implementation of the transfer functions
+ described in the milspec.
+
+ To use one of these two models, set <tt>atmosphere/turb-type</tt> to 4 resp. 5,
+ and specify values for <tt>atmosphere/turbulence/milspec/windspeed_at_20ft_AGL-fps<tt>
+ and <tt>atmosphere/turbulence/milspec/severity<tt> (the latter corresponds to
+ the probability of exceedence curves from Fig. 7 of the milspec, allowable
+ range is 0 (disabled) to 7). <tt>atmosphere/psiw-rad</tt> is respected as well;
+ note that you have to specify a positive wind magnitude to prevent psiw from
+ being reset to zero.
+
+ Reference values (cf. figures 7 and 9 from the milspec):
+ <table>
+ <tr><td><b>Intensity</b></td>
+ <td><b><tt>windspeed_at_20ft_AGL-fps</tt></b></td>
+ <td><b><tt>severity</tt></b></td></tr>
+ <tr><td>light</td>
+ <td>25 (15 knots)</td>
+ <td>3</td></tr>
+ <tr><td>moderate</td>
+ <td>50 (30 knots)</td>
+ <td>4</td></tr>
+ <tr><td>severe</td>
+ <td>75 (45 knots)</td>
+ <td>6</td></tr>
+ </table>
+
+ @see Yeager, Jessie C.: "Implementation and Testing of Turbulence Models for
+ the F18-HARV" (<a
+ href="http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19980028448_1998081596.pdf">
+ pdf</a>), NASA CR-1998-206937, 1998
+
+ @see MIL-F-8785C: Military Specification: Flying Qualities of Piloted Aircraft
+
*/
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@return false if no error */
bool Run(void);
bool InitModel(void);
- enum tType {ttStandard, ttBerndt, ttCulp, ttNone} turbType;
+ enum tType {ttNone, ttStandard, ttBerndt, ttCulp, ttMilspec, ttTustin} turbType;
/// Returns the temperature in degrees Rankine.
- inline double GetTemperature(void) const {return *temperature;}
+ double GetTemperature(void) const {return *temperature;}
/** Returns the density in slugs/ft^3.
<i>This function may <b>only</b> be used if Run() is called first.</i> */
- inline double GetDensity(void) const {return *density;}
+ double GetDensity(void) const {return *density;}
/// Returns the pressure in psf.
double GetPressure(void) const {return *pressure;}
/// Returns the standard pressure at a specified altitude
/// Returns the standard density at a specified altitude
double GetDensity(double altitude);
/// Returns the speed of sound in ft/sec.
- inline double GetSoundSpeed(void) const {return soundspeed;}
+ double GetSoundSpeed(void) const {return soundspeed;}
+ /// Returns the absolute viscosity.
+ double GetAbsoluteViscosity(void) const {return intViscosity;}
+ /// Returns the kinematic viscosity.
+ double GetKinematicViscosity(void) const {return intKinematicViscosity;}
/// Returns the sea level temperature in degrees Rankine.
- inline double GetTemperatureSL(void) const { return SLtemperature; }
+ double GetTemperatureSL(void) const { return SLtemperature; }
/// Returns the sea level density in slugs/ft^3
- inline double GetDensitySL(void) const { return SLdensity; }
+ double GetDensitySL(void) const { return SLdensity; }
/// Returns the sea level pressure in psf.
- inline double GetPressureSL(void) const { return SLpressure; }
+ double GetPressureSL(void) const { return SLpressure; }
/// Returns the sea level speed of sound in ft/sec.
- inline double GetSoundSpeedSL(void) const { return SLsoundspeed; }
+ double GetSoundSpeedSL(void) const { return SLsoundspeed; }
/// Returns the ratio of at-altitude temperature over the sea level value.
- inline double GetTemperatureRatio(void) const { return (*temperature)*rSLtemperature; }
+ double GetTemperatureRatio(void) const { return (*temperature)*rSLtemperature; }
/// Returns the ratio of at-altitude density over the sea level value.
- inline double GetDensityRatio(void) const { return (*density)*rSLdensity; }
+ double GetDensityRatio(void) const { return (*density)*rSLdensity; }
/// Returns the ratio of at-altitude pressure over the sea level value.
- inline double GetPressureRatio(void) const { return (*pressure)*rSLpressure; }
+ double GetPressureRatio(void) const { return (*pressure)*rSLpressure; }
/// Returns the ratio of at-altitude sound speed over the sea level value.
- inline double GetSoundSpeedRatio(void) const { return soundspeed*rSLsoundspeed; }
+ double GetSoundSpeedRatio(void) const { return soundspeed*rSLsoundspeed; }
/// Tells the simulator to use an externally calculated atmosphere model.
void UseExternal(void);
bool External(void) { return useExternal; }
/// Provides the external atmosphere model with an interface to set the temperature.
- inline void SetExTemperature(double t) { exTemperature=t; }
+ void SetExTemperature(double t) { exTemperature=t; }
/// Provides the external atmosphere model with an interface to set the density.
- inline void SetExDensity(double d) { exDensity=d; }
+ void SetExDensity(double d) { exDensity=d; }
/// Provides the external atmosphere model with an interface to set the pressure.
- inline void SetExPressure(double p) { exPressure=p; }
+ void SetExPressure(double p) { exPressure=p; }
/// Sets the temperature deviation at sea-level in degrees Fahrenheit
- inline void SetSLTempDev(double d) { T_dev_sl = d; }
+ void SetSLTempDev(double d) { T_dev_sl = d; }
/// Gets the temperature deviation at sea-level in degrees Fahrenheit
- inline double GetSLTempDev(void) const { return T_dev_sl; }
+ double GetSLTempDev(void) const { return T_dev_sl; }
/// Sets the current delta-T in degrees Fahrenheit
- inline void SetDeltaT(double d) { delta_T = d; }
+ void SetDeltaT(double d) { delta_T = d; }
/// Gets the current delta-T in degrees Fahrenheit
- inline double GetDeltaT(void) const { return delta_T; }
+ double GetDeltaT(void) const { return delta_T; }
/// Gets the at-altitude temperature deviation in degrees Fahrenheit
- inline double GetTempDev(void) const { return T_dev; }
+ double GetTempDev(void) const { return T_dev; }
/// Gets the density altitude in feet
- inline double GetDensityAltitude(void) const { return density_altitude; }
+ double GetDensityAltitude(void) const { return density_altitude; }
+
+ // TOTAL WIND access functions (wind + gust + turbulence)
+
+ /// Retrieves the total wind components in NED frame.
+ const FGColumnVector3& GetTotalWindNED(void) const { return vTotalWindNED; }
+
+ /// Retrieves a total wind component in NED frame.
+ double GetTotalWindNED(int idx) const {return vTotalWindNED(idx);}
+
+ // WIND access functions
/// Sets the wind components in NED frame.
- inline void SetWindNED(double wN, double wE, double wD) { vWindNED(1)=wN; vWindNED(2)=wE; vWindNED(3)=wD;}
+ void SetWindNED(double wN, double wE, double wD) { vWindNED(1)=wN; vWindNED(2)=wE; vWindNED(3)=wD;}
+
+ /// Sets a wind component in NED frame.
+ void SetWindNED(int idx, double wind) { vWindNED(idx)=wind;}
/// Retrieves the wind components in NED frame.
- inline FGColumnVector3& GetWindNED(void) { return vWindNED; }
+ FGColumnVector3& GetWindNED(void) { return vWindNED; }
- /// Sets gust components in NED frame.
- inline void SetGustNED(int idx, double gust) { vGustNED(idx)=gust;}
+ /// Retrieves a wind component in NED frame.
+ double GetWindNED(int idx) const {return vWindNED(idx);}
- /// Retrieves the gust components in NED frame.
- inline double GetGustNED(int idx) const {return vGustNED(idx);}
+ /** Retrieves the direction that the wind is coming from.
+ The direction is defined as north=0 and increases counterclockwise.
+ The wind heading is returned in radians.*/
+ double GetWindPsi(void) const { return psiw; }
- /// Retrieves the gust components in NED frame.
- inline FGColumnVector3& GetGustNED(void) {return vGustNED;}
+ /** Sets the direction that the wind is coming from.
+ The direction is defined as north=0 and increases counterclockwise to 2*pi (radians). The
+ vertical component of wind is assumed to be zero - and is forcibly set to zero. This function
+ sets the vWindNED vector components based on the supplied direction. The magnitude of
+ the wind set in the vector is preserved (assuming the vertical component is non-zero).
+ @param dir wind direction in the horizontal plane, in radians.*/
+ void SetWindPsi(double dir);
- /** Retrieves the wind direction. The direction is defined as north=0 and
- increases counterclockwise. The wind heading is returned in radians.*/
- inline double GetWindPsi(void) const { return psiw; }
+ void SetWindspeed(double speed);
- /** Turbulence models available: ttStandard, ttBerndt, ttCulp, ttNone */
- inline void SetTurbType(tType tt) {turbType = tt;}
- inline tType GetTurbType() const {return turbType;}
+ double GetWindspeed(void) const;
- inline void SetTurbGain(double tg) {TurbGain = tg;}
- inline double GetTurbGain() const {return TurbGain;}
+ // GUST access functions
- inline void SetTurbRate(double tr) {TurbRate = tr;}
- inline double GetTurbRate() const {return TurbRate;}
+ /// Sets a gust component in NED frame.
+ void SetGustNED(int idx, double gust) { vGustNED(idx)=gust;}
- inline void SetRhythmicity(double r) {Rhythmicity=r;}
- inline double GetRhythmicity() const {return Rhythmicity;}
+ /// Sets a turbulence component in NED frame.
+ void SetTurbNED(int idx, double turb) { vTurbulenceNED(idx)=turb;}
- /** Sets wind vortex, clockwise as seen from a point in front of aircraft,
- looking aft. Units are radians/second. */
- inline void SetWindFromClockwise(double wC) { wind_from_clockwise=wC; }
- inline double GetWindFromClockwise(void) const {return wind_from_clockwise;}
+ /// Sets the gust components in NED frame.
+ void SetGustNED(double gN, double gE, double gD) { vGustNED(eNorth)=gN; vGustNED(eEast)=gE; vGustNED(eDown)=gD;}
- inline double GetTurbPQR(int idx) const {return vTurbPQR(idx);}
+ /// Retrieves a gust component in NED frame.
+ double GetGustNED(int idx) const {return vGustNED(idx);}
+
+ /// Retrieves a turbulence component in NED frame.
+ double GetTurbNED(int idx) const {return vTurbulenceNED(idx);}
+
+ /// Retrieves the gust components in NED frame.
+ FGColumnVector3& GetGustNED(void) {return vGustNED;}
+
+ /** Turbulence models available: ttNone, ttStandard, ttBerndt, ttCulp, ttMilspec, ttTustin */
+ void SetTurbType(tType tt) {turbType = tt;}
+ tType GetTurbType() const {return turbType;}
+
+ void SetTurbGain(double tg) {TurbGain = tg;}
+ double GetTurbGain() const {return TurbGain;}
+
+ void SetTurbRate(double tr) {TurbRate = tr;}
+ double GetTurbRate() const {return TurbRate;}
+
+ void SetRhythmicity(double r) {Rhythmicity=r;}
+ double GetRhythmicity() const {return Rhythmicity;}
+
+ double GetTurbPQR(int idx) const {return vTurbPQR(idx);}
double GetTurbMagnitude(void) const {return Magnitude;}
- FGColumnVector3& GetTurbDirection(void) {return vDirection;}
- inline FGColumnVector3& GetTurbPQR(void) {return vTurbPQR;}
+ const FGColumnVector3& GetTurbDirection(void) const {return vDirection;}
+ const FGColumnVector3& GetTurbPQR(void) const {return vTurbPQR;}
+
+ void SetWindspeed20ft(double ws) { windspeed_at_20ft = ws;}
+ double GetWindspeed20ft() const { return windspeed_at_20ft;}
+
+ /// allowable range: 0-7, 3=light, 4=moderate, 6=severe turbulence
+ void SetProbabilityOfExceedence( int idx) {probability_of_exceedence_index = idx;}
+ int GetProbabilityOfExceedence() const { return probability_of_exceedence_index;}
protected:
double rho;
bool useExternal;
double exTemperature,exDensity,exPressure;
double intTemperature, intDensity, intPressure;
+ double SutherlandConstant, Beta, intViscosity, intKinematicViscosity;
double T_dev_sl, T_dev, delta_T, density_altitude;
atmType atmosphere;
bool StandardTempOnly;
FGColumnVector3 vDirectiondAccelDt;
FGColumnVector3 vDirectionAccel;
FGColumnVector3 vDirection;
- FGColumnVector3 vTurbulence;
FGColumnVector3 vTurbulenceGrad;
FGColumnVector3 vBodyTurbGrad;
FGColumnVector3 vTurbPQR;
- FGColumnVector3 vWindNED;
- double psiw;
+ // Dryden turbulence model
+ double windspeed_at_20ft; ///< in ft/s
+ int probability_of_exceedence_index; ///< this is bound as the severity property
+ FGTable *POE_Table; ///< probability of exceedence table
+ double psiw;
+ FGColumnVector3 vTotalWindNED;
+ FGColumnVector3 vWindNED;
FGColumnVector3 vGustNED;
- bool bgustSet;
+ FGColumnVector3 vTurbulenceNED;
/// Calculate the atmosphere for the given altitude, including effects of temperature deviation.
void Calculate(double altitude);
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