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.
double GetTemperature(void) const {return *temperature;}
// TOTAL WIND access functions (wind + gust + turbulence)
/// Retrieves the total wind components in NED frame.
- FGColumnVector3& GetTotalWindNED(void) { return vTotalWindNED; }
+ const FGColumnVector3& GetTotalWindNED(void) const { return vTotalWindNED; }
/// Retrieves a total wind component in NED frame.
double GetTotalWindNED(int idx) const {return vTotalWindNED(idx);}
/// Sets a gust component in NED frame.
void SetGustNED(int idx, double gust) { vGustNED(idx)=gust;}
+ /// Sets a turbulence component in NED frame.
+ void SetTurbNED(int idx, double turb) { vTurbulenceNED(idx)=turb;}
+
/// Sets the gust components in NED frame.
void SetGustNED(double gN, double gE, double gD) { vGustNED(eNorth)=gN; vGustNED(eEast)=gE; vGustNED(eDown)=gD;}
/// 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: ttStandard, ttBerndt, ttCulp, ttNone */
+ /** Turbulence models available: ttNone, ttStandard, ttBerndt, ttCulp, ttMilspec, ttTustin */
void SetTurbType(tType tt) {turbType = tt;}
tType GetTurbType() const {return turbType;}
double GetTurbPQR(int idx) const {return vTurbPQR(idx);}
double GetTurbMagnitude(void) const {return Magnitude;}
- FGColumnVector3& GetTurbDirection(void) {return vDirection;}
- 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;
FGColumnVector3 vBodyTurbGrad;
FGColumnVector3 vTurbPQR;
+ // 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;
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