#include "FGAuxiliary.h"
#include "FGOutput.h"
#include "FGDefs.h"
+#include "FGMatrix.h"
/*******************************************************************************
************************************ CODE **************************************
*******************************************************************************/
-FGAtmosphere::FGAtmosphere(FGFDMExec* fdmex) : FGModel(fdmex)
+FGAtmosphere::FGAtmosphere(FGFDMExec* fdmex) : FGModel(fdmex),vWindUVW(3),vWindNED(3)
{
- Name = "FGAtmosphere";
- h=0;
- Calculate();
+ Name = "FGAtmosphere";
+ h = 0;
+ Calculate(h);
+ SLtemperature = temperature;
+ SLpressure = pressure;
+ SLdensity = density;
+ SLsoundspeed = sqrt(SHRATIO*Reng*temperature);
+ useExternal=false;
+ vWindUVW(1)=0;vWindUVW(2)=0;vWindUVW(3)=0;
+ vWindNED(1)=0;vWindNED(2)=0;vWindNED(3)=0;
}
bool FGAtmosphere::Run(void)
{
- if (!FGModel::Run()) { // if false then execute this Run()
- h = State->Geth();
- Calculate();
- State->Seta(soundspeed);
- } else { // skip Run() execution this time
- }
- return false;
-}
-
-
-float FGAtmosphere::CalcRho(float altitude)
-{
- return (0.00237 - 7.0E-08*altitude
- + 7.0E-13*altitude*altitude
- - 2.0E-18*altitude*altitude*altitude);
-}
-
-
-void FGAtmosphere::Calculate(void)
-{
- //see reference [1]
-
- float slope,reftemp,refpress,refdens;
- int i=0;
- float htab[]={0,36089,82020,154198,173882,259183,295272,344484}; //ft.
-
- if (h <= htab[0]) {
- h=0;
- } else if (h >= htab[7]){
- i = 7;
- h = htab[7];
- } else {
- while (htab[i+1] < h) {
- i++;
+ //cout << "In FGAtmosphere::Run(void)" << endl;
+ if (!FGModel::Run()) { // if false then execute this Run()
+ //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;
+ //switch sign of wind components so that they are
+ //in aircraft reference frame. The classic example is
+ //takeoff or landing where you always want to fly
+ //into the wind. Suppose that an aircraft is
+ //taking off into the wind on the runway heading
+ //of pure north. Into the wind means the wind is
+ //flowing to the south (or negative) direction,
+ //and we know that headwinds increase the relative
+ //velocity, so to make a positive delta U from the
+ //southerly wind the sign must be switched.
+ vWindNED *= -1;
+ vWindUVW = State->GetTl2b()*vWindNED;
+ }
+ soundspeed = sqrt(SHRATIO*Reng*temperature);
+ //cout << "Atmosphere: soundspeed: " << soundspeed << endl;
+ State->Seta(soundspeed);
+
+
+ } else { // skip Run() execution this time
}
- }
-
- 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)*(h-htab[i]));
- density = refdens*exp(-GRAVITY/(reftemp*Reng)*(h-htab[i]));
- } else {
- temperature = reftemp+slope*(h-htab[i]);
- pressure = refpress*pow(temperature/reftemp,-GRAVITY/(slope*Reng));
- density = refdens*pow(temperature/reftemp,-(GRAVITY/(slope*Reng)+1));
- }
-
- soundspeed = sqrt(SHRATIO*Reng*temperature);
-
+ return false;
}
-float FGAtmosphere::GetTemperature(float altitude)
+void FGAtmosphere::Calculate(float altitude)
{
- if (altitude != h) {
- h = altitude;
- Calculate();
- }
- return temperature;
-}
+ //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;
+ }
-float FGAtmosphere::GetPressure(float altitude)
-{
- if (altitude != h) {
- h = altitude;
- Calculate();
- }
- return pressure;
-}
+ 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));
+ }
-float FGAtmosphere::GetDensity(float altitude)
-{
- if (altitude != h) {
- h = altitude;
- Calculate();
- }
+ //cout << "Atmosphere: h=" << altitude << " rho= " << density << endl;
- return density;
}
-float FGAtmosphere::GetSoundSpeed(float altitude)
-{
- if (altitude != h) {
- h = altitude;
- Calculate();
- }
- return soundspeed;
-}
projects / flightgear.git / blobdiff