1 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3 Module: FGAtmosphere.cpp
5 Implementation of 1959 Standard Atmosphere added by Tony Peden
7 Purpose: Models the atmosphere
10 ------------- Copyright (C) 1999 Jon S. Berndt (jsb@hal-pc.org) -------------
12 This program is free software; you can redistribute it and/or modify it under
13 the terms of the GNU General Public License as published by the Free Software
14 Foundation; either version 2 of the License, or (at your option) any later
17 This program is distributed in the hope that it will be useful, but WITHOUT
18 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
19 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
22 You should have received a copy of the GNU General Public License along with
23 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
24 Place - Suite 330, Boston, MA 02111-1307, USA.
26 Further information about the GNU General Public License can also be found on
27 the world wide web at http://www.gnu.org.
29 FUNCTIONAL DESCRIPTION
30 --------------------------------------------------------------------------------
31 Models the atmosphere. The equation used below was determined by a third order
32 curve fit using Excel. The data is from the ICAO atmosphere model.
35 --------------------------------------------------------------------------------
37 07/23/99 TP Added implementation of 1959 Standard Atmosphere
38 Moved calculation of Mach number to FGTranslation
39 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
40 COMMENTS, REFERENCES, and NOTES
41 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
42 [1] Anderson, John D. "Introduction to Flight, Third Edition", McGraw-Hill,
43 1989, ISBN 0-07-001641-0
45 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
47 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
49 #include "FGAtmosphere.h"
51 #include "FGFDMExec.h"
53 #include "FGAircraft.h"
54 #include "FGTranslation.h"
55 #include "FGRotation.h"
56 #include "FGPosition.h"
57 #include "FGAuxiliary.h"
59 #include "FGMatrix33.h"
60 #include "FGColumnVector3.h"
61 #include "FGColumnVector4.h"
62 #include "FGPropertyManager.h"
64 static const char *IdSrc = "$Id$";
65 static const char *IdHdr = ID_ATMOSPHERE;
67 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
69 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
72 FGAtmosphere::FGAtmosphere(FGFDMExec* fdmex) : FGModel(fdmex)
74 Name = "FGAtmosphere";
84 htab[7]=259186.352; //ft.
86 MagnitudedAccelDt = MagnitudeAccel = Magnitude = 0.0;
88 // turbType = ttBerndt; // temporarily disable turbulence until fully tested
95 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
97 FGAtmosphere::~FGAtmosphere()
103 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
105 bool FGAtmosphere::InitModel(void)
107 FGModel::InitModel();
110 SLtemperature = temperature;
111 SLpressure = pressure;
113 SLsoundspeed = sqrt(SHRatio*Reng*temperature);
114 rSLtemperature = 1.0/temperature;
115 rSLpressure = 1.0/pressure;
116 rSLdensity = 1.0/density;
117 rSLsoundspeed = 1.0/SLsoundspeed;
123 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
125 bool FGAtmosphere::Run(void)
127 if (!FGModel::Run()) { // if false then execute this Run()
128 //do temp, pressure, and density first
130 h = Position->Geth();
134 pressure = exPressure;
135 temperature = exTemperature;
138 if (turbType != ttNone) {
140 vWindNED += vTurbulence;
143 if (vWindNED(1) != 0.0) psiw = atan2( vWindNED(2), vWindNED(1) );
145 if (psiw < 0) psiw += 2*M_PI;
147 soundspeed = sqrt(SHRatio*Reng*temperature);
149 State->Seta(soundspeed);
153 } else { // skip Run() execution this time
159 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
163 void FGAtmosphere::Calculate(double altitude)
165 double slope, reftemp, refpress;
169 if (altitude < htab[lastIndex]) {
175 while (htab[i] > altitude) i--;
177 } else if (altitude > htab[lastIndex+1]){
178 if (altitude >= htab[7]){
183 while(htab[i+1] < altitude) i++;
192 //refdens = 0.000706032;
198 //refdens = 0.000171306;
200 case 3: // 104986 ft.
204 //refdens = 1.18422e-05;
206 case 4: // 154199 ft.
210 //refdens = 4.00585e-7;
212 case 5: // 170603 ft.
216 //refdens = 8.17102e-7;
218 case 6: // 200131 ft.
221 refpress = 0.00684986;
222 //refdens = 8.77702e-9;
224 case 7: // 259186 ft.
227 refpress = 0.000122276;
228 //refdens = 2.19541e-10;
231 default: // sea level
232 slope = -0.00356616; // R/ft.
233 reftemp = 518.67; // R
234 refpress = 2116.22; // psf
235 //refdens = 0.00237767; // slugs/cubic ft.
241 temperature = reftemp;
242 pressure = refpress*exp(-Inertial->SLgravity()/(reftemp*Reng)*(altitude-htab[i]));
243 //density = refdens*exp(-Inertial->SLgravity()/(reftemp*Reng)*(altitude-htab[i]));
244 density = pressure/(Reng*temperature);
246 temperature = reftemp+slope*(altitude-htab[i]);
247 pressure = refpress*pow(temperature/reftemp,-Inertial->SLgravity()/(slope*Reng));
248 //density = refdens*pow(temperature/reftemp,-(Inertial->SLgravity()/(slope*Reng)+1));
249 density = pressure/(Reng*temperature);
252 //cout << "Atmosphere: h=" << altitude << " rho= " << density << endl;
255 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
257 void FGAtmosphere::Turbulence(void)
261 vDirectiondAccelDt(eX) = 1 - 2.0*(((double)(rand()))/RAND_MAX);
262 vDirectiondAccelDt(eY) = 1 - 2.0*(((double)(rand()))/RAND_MAX);
263 vDirectiondAccelDt(eZ) = 1 - 2.0*(((double)(rand()))/RAND_MAX);
265 MagnitudedAccelDt = 1 - 2.0*(((double)(rand()))/RAND_MAX);
266 MagnitudeAccel += MagnitudedAccelDt*rate*State->Getdt();
267 Magnitude += MagnitudeAccel*rate*State->Getdt();
269 vDirectiondAccelDt.Normalize();
270 vDirectionAccel += vDirectiondAccelDt*rate*State->Getdt();
271 vDirectionAccel.Normalize();
272 vDirection += vDirectionAccel*rate*State->Getdt();
273 vDirection.Normalize();
275 vTurbulence = TurbGain*Magnitude * vDirection;
276 vTurbulenceGrad = TurbGain*MagnitudeAccel * vDirection;
278 vBodyTurbGrad = State->GetTl2b()*vTurbulenceGrad;
279 vTurbPQR(eP) = vBodyTurbGrad(eY)/Aircraft->GetWingSpan();
280 if (Aircraft->GetHTailArm() != 0.0)
281 vTurbPQR(eQ) = vBodyTurbGrad(eZ)/Aircraft->GetHTailArm();
283 vTurbPQR(eQ) = vBodyTurbGrad(eZ)/10.0;
285 if (Aircraft->GetVTailArm())
286 vTurbPQR(eR) = vBodyTurbGrad(eX)/Aircraft->GetVTailArm();
288 vTurbPQR(eR) = vBodyTurbGrad(eX)/10.0;
296 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
297 // The bitmasked value choices are as follows:
298 // unset: In this case (the default) JSBSim would only print
299 // out the normally expected messages, essentially echoing
300 // the config files as they are read. If the environment
301 // variable is not set, debug_lvl is set to 1 internally
302 // 0: This requests JSBSim not to output any messages
304 // 1: This value explicity requests the normal JSBSim
306 // 2: This value asks for a message to be printed out when
307 // a class is instantiated
308 // 4: When this value is set, a message is displayed when a
309 // FGModel object executes its Run() method
310 // 8: When this value is set, various runtime state variables
311 // are printed out periodically
312 // 16: When set various parameters are sanity checked and
313 // a message is printed out when they go out of bounds
315 void FGAtmosphere::Debug(int from)
317 if (debug_lvl <= 0) return;
319 if (debug_lvl & 1) { // Standard console startup message output
320 if (from == 0) { // Constructor
323 if (debug_lvl & 2 ) { // Instantiation/Destruction notification
324 if (from == 0) cout << "Instantiated: FGAtmosphere" << endl;
325 if (from == 1) cout << "Destroyed: FGAtmosphere" << endl;
327 if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
329 if (debug_lvl & 8 ) { // Runtime state variables
331 if (debug_lvl & 16) { // Sanity checking
333 if (debug_lvl & 32) { // Turbulence
334 if (frame == 0 && from == 2) {
335 cout << "vTurbulence(X), vTurbulence(Y), vTurbulence(Z), "
336 << "vTurbulenceGrad(X), vTurbulenceGrad(Y), vTurbulenceGrad(Z), "
337 << "vDirection(X), vDirection(Y), vDirection(Z), "
339 << "vTurbPQR(P), vTurbPQR(Q), vTurbPQR(R), " << endl;
340 } else if (from == 2) {
341 cout << vTurbulence << ", " << vTurbulenceGrad << ", " << vDirection << ", " << Magnitude << ", " << vTurbPQR << endl;
344 if (debug_lvl & 64) {
345 if (from == 0) { // Constructor
346 cout << IdSrc << endl;
347 cout << IdHdr << endl;
352 void FGAtmosphere::bind(void){
353 PropertyManager->Tie("atmosphere/T-R", this,
354 &FGAtmosphere::GetTemperature);
355 PropertyManager->Tie("atmosphere/rho-slugs_ft3", this,
356 &FGAtmosphere::GetDensity);
357 PropertyManager->Tie("atmosphere/P-psf", this,
358 &FGAtmosphere::GetPressure);
359 PropertyManager->Tie("atmosphere/a-fps", this,
360 &FGAtmosphere::GetSoundSpeed);
361 PropertyManager->Tie("atmosphere/T-sl-R", this,
362 &FGAtmosphere::GetTemperatureSL);
363 PropertyManager->Tie("atmosphere/rho-sl-slugs_ft3", this,
364 &FGAtmosphere::GetDensitySL);
365 PropertyManager->Tie("atmosphere/P-sl-psf", this,
366 &FGAtmosphere::GetPressureSL);
367 PropertyManager->Tie("atmosphere/a-sl-fps", this,
368 &FGAtmosphere::GetSoundSpeedSL);
369 PropertyManager->Tie("atmosphere/theta-norm", this,
370 &FGAtmosphere::GetTemperatureRatio);
371 PropertyManager->Tie("atmosphere/sigma-norm", this,
372 &FGAtmosphere::GetDensityRatio);
373 PropertyManager->Tie("atmosphere/delta-norm", this,
374 &FGAtmosphere::GetPressureRatio);
375 PropertyManager->Tie("atmosphere/a-norm", this,
376 &FGAtmosphere::GetSoundSpeedRatio);
377 PropertyManager->Tie("atmosphere/psiw-rad", this,
378 &FGAtmosphere::GetWindPsi);
379 PropertyManager->Tie("atmosphere/p-turb-rad_sec", this,1,
380 &FGAtmosphere::GetTurbPQR);
381 PropertyManager->Tie("atmosphere/q-turb-rad_sec", this,2,
382 &FGAtmosphere::GetTurbPQR);
383 PropertyManager->Tie("atmosphere/r-turb-rad_sec", this,3,
384 &FGAtmosphere::GetTurbPQR);
387 void FGAtmosphere::unbind(void){
388 PropertyManager->Untie("atmosphere/T-R");
389 PropertyManager->Untie("atmosphere/rho-slugs_ft3");
390 PropertyManager->Untie("atmosphere/P-psf");
391 PropertyManager->Untie("atmosphere/a-fps");
392 PropertyManager->Untie("atmosphere/T-sl-R");
393 PropertyManager->Untie("atmosphere/rho-sl-slugs_ft3");
394 PropertyManager->Untie("atmosphere/P-sl-psf");
395 PropertyManager->Untie("atmosphere/a-sl-fps");
396 PropertyManager->Untie("atmosphere/theta-norm");
397 PropertyManager->Untie("atmosphere/sigma-norm");
398 PropertyManager->Untie("atmosphere/delta-norm");
399 PropertyManager->Untie("atmosphere/a-norm");
400 PropertyManager->Untie("atmosphere/psiw-rad");
401 PropertyManager->Untie("atmosphere/p-turb-rad_sec");
402 PropertyManager->Untie("atmosphere/q-turb-rad_sec");
403 PropertyManager->Untie("atmosphere/r-turb-rad_sec");