-/*******************************************************************************
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Module: FGAtmosphere.cpp
Author: Jon Berndt
+ Implementation of 1959 Standard Atmosphere added by Tony Peden
Date started: 11/24/98
Purpose: Models the atmosphere
Called by: FGSimExec
HISTORY
--------------------------------------------------------------------------------
11/24/98 JSB Created
-
-********************************************************************************
+07/23/99 TP Added implementation of 1959 Standard Atmosphere
+ Moved calculation of Mach number to FGTranslation
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+COMMENTS, REFERENCES, and NOTES
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+[1] Anderson, John D. "Introduction to Flight, Third Edition", McGraw-Hill,
+ 1989, ISBN 0-07-001641-0
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
INCLUDES
-*******************************************************************************/
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
#include "FGAtmosphere.h"
#include "FGState.h"
#include "FGPosition.h"
#include "FGAuxiliary.h"
#include "FGOutput.h"
+#include "FGDefs.h"
+#include "FGMatrix.h"
+
+static const char *IdSrc = "$Id$";
+static const char *IdHdr = ID_ATMOSPHERE;
+
+extern short debug_lvl;
-/*******************************************************************************
-************************************ CODE **************************************
-*******************************************************************************/
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+CLASS IMPLEMENTATION
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-FGAtmosphere::FGAtmosphere(FGFDMExec* fdmex) : FGModel(fdmex)
+
+FGAtmosphere::FGAtmosphere(FGFDMExec* fdmex) : FGModel(fdmex),
+ vWindNED(3)
{
Name = "FGAtmosphere";
+ h = 0;
+ Calculate(h);
+ SLtemperature = temperature;
+ SLpressure = pressure;
+ SLdensity = density;
+ SLsoundspeed = sqrt(SHRATIO*Reng*temperature);
+ useExternal=false;
+
+ if (debug_lvl & 2) cout << "Instantiated: " << Name << endl;
}
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
FGAtmosphere::~FGAtmosphere()
{
+ if (debug_lvl & 2) cout << "Destroyed: FGAtmosphere" << endl;
}
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
bool FGAtmosphere::Run(void)
{
+ //cout << "In FGAtmosphere::Run(void)" << endl;
if (!FGModel::Run()) { // if false then execute this Run()
- rho = 0.002377 - 7.0E-08*State->Geth()
- + 7.0E-13*State->Geth()*State->Geth()
- - 2.0E-18*State->Geth()*State->Geth()*State->Geth();
+ //do temp, pressure, and density first
+ if (!useExternal) {
+ //cout << "Atmosphere: Using internal model, altitude= ";
+ h = Position->Geth();
+
+ Calculate(h);
+ } else {
+ density = exDensity;
+ pressure = exPressure;
+ temperature = exTemperature;
+ }
+
+ if (vWindNED(1) != 0.0) psiw = atan2( vWindNED(2), vWindNED(1) );
+
+ if (psiw < 0) psiw += 2*M_PI;
+
+ soundspeed = sqrt(SHRATIO*Reng*temperature);
+ //cout << "Atmosphere: soundspeed: " << soundspeed << endl;
+ State->Seta(soundspeed);
- State->SetMach(State->GetVt()/State->Geta());
} else { // skip Run() execution this time
}
return false;
}
-float FGAtmosphere::CalcRho(float altitude)
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+void FGAtmosphere::Calculate(float altitude)
{
- return (0.002377 - 7.0E-08*altitude
- + 7.0E-13*altitude*altitude
- - 2.0E-18*altitude*altitude*altitude);
+ //see reference [1]
+
+ float slope,reftemp,refpress,refdens;
+ int i=0;
+ float htab[]={0,36089,82020,154198,173882,259183,295272,344484}; //ft.
+ // cout << "Atmosphere: h=" << altitude << " rho= " << density << endl;
+ if (altitude <= htab[0]) {
+ altitude=0;
+ } else if (altitude >= htab[7]){
+ i = 7;
+ altitude = htab[7];
+ } else {
+ while (htab[i+1] < altitude) {
+ i++;
+ }
+ }
+ switch(i) {
+ case 0: // sea level
+ slope = -0.0035662; // R/ft.
+ reftemp = 518.688; // R
+ refpress = 2116.17; // psf
+ refdens = 0.0023765; // slugs/cubic ft.
+ break;
+ case 1: // 36089 ft.
+ slope = 0;
+ reftemp = 389.988;
+ refpress = 474.1;
+ refdens = 0.0007078;
+ break;
+ case 2: // 82020 ft.
+ slope = 0.00164594;
+ reftemp = 389.988;
+ refpress = 52.7838;
+ refdens = 7.8849E-5;
+ break;
+ case 3: // 154198 ft.
+ slope = 0;
+ reftemp = 508.788;
+ refpress = 2.62274;
+ refdens = 3.01379E-6;
+ break;
+ case 4: // 173882 ft.
+ slope = -0.00246891;
+ reftemp = 508.788;
+ refpress = 1.28428;
+ refdens = 1.47035e-06;
+ break;
+ case 5: // 259183 ft.
+ slope = 0;
+ reftemp = 298.188;
+ refpress = 0.0222008;
+ refdens = 4.33396e-08;
+ break;
+ case 6: // 295272 ft.
+ slope = 0.00219459;
+ reftemp = 298.188;
+ refpress = 0.00215742;
+ refdens = 4.21368e-09;
+ break;
+ case 7: // 344484 ft.
+ slope = 0;
+ reftemp = 406.188;
+ refpress = 0.000153755;
+ refdens = 2.20384e-10;
+ break;
+ }
+
+ if (slope == 0) {
+ temperature = reftemp;
+ pressure = refpress*exp(-GRAVITY/(reftemp*Reng)*(altitude-htab[i]));
+ density = refdens*exp(-GRAVITY/(reftemp*Reng)*(altitude-htab[i]));
+ } else {
+ temperature = reftemp+slope*(altitude-htab[i]);
+ pressure = refpress*pow(temperature/reftemp,-GRAVITY/(slope*Reng));
+ density = refdens*pow(temperature/reftemp,-(GRAVITY/(slope*Reng)+1));
+ }
+
+ //cout << "Atmosphere: h=" << altitude << " rho= " << density << endl;
+
+}
+
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+void FGAtmosphere::Debug(void)
+{
+ //TODO: Add your source code here
}
projects / flightgear.git / blobdiff