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 Later updated to '76 model
40 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
41 COMMENTS, REFERENCES, and NOTES
42 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
43 [1] Anderson, John D. "Introduction to Flight, Third Edition", McGraw-Hill,
44 1989, ISBN 0-07-001641-0
46 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
48 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
50 #include "FGAtmosphere.h"
52 #include "FGFDMExec.h"
54 #include "FGAircraft.h"
55 #include "FGTranslation.h"
56 #include "FGRotation.h"
57 #include "FGPosition.h"
58 #include "FGAuxiliary.h"
60 #include "FGMatrix33.h"
61 #include "FGColumnVector3.h"
62 #include "FGColumnVector4.h"
63 #include "FGPropertyManager.h"
67 static const char *IdSrc = "$Id$";
68 static const char *IdHdr = ID_ATMOSPHERE;
70 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
72 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
75 FGAtmosphere::FGAtmosphere(FGFDMExec* fdmex) : FGModel(fdmex)
77 Name = "FGAtmosphere";
88 htab[7]=259186.352; //ft.
90 MagnitudedAccelDt = MagnitudeAccel = Magnitude = 0.0;
92 turbType = ttStandard;
93 // turbType = ttBerndt;
100 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
102 FGAtmosphere::~FGAtmosphere()
108 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
110 bool FGAtmosphere::InitModel(void)
112 FGModel::InitModel();
115 SLtemperature = intTemperature;
116 SLpressure = intPressure;
117 SLdensity = intDensity;
118 SLsoundspeed = sqrt(SHRatio*Reng*intTemperature);
119 rSLtemperature = 1.0/intTemperature;
120 rSLpressure = 1.0/intPressure;
121 rSLdensity = 1.0/intDensity;
122 rSLsoundspeed = 1.0/SLsoundspeed;
123 temperature=&intTemperature;
124 pressure=&intPressure;
132 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
134 bool FGAtmosphere::Run(void)
136 if (!FGModel::Run()) { // if false then execute this Run()
137 //do temp, pressure, and density first
139 h = Position->Geth();
143 if (turbType != ttNone) {
145 vWindNED += vTurbulence;
148 if (vWindNED(1) != 0.0) psiw = atan2( vWindNED(2), vWindNED(1) );
150 if (psiw < 0) psiw += 2*M_PI;
152 soundspeed = sqrt(SHRatio*Reng*(*temperature));
154 State->Seta(soundspeed);
159 } else { // skip Run() execution this time
164 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
168 void FGAtmosphere::Calculate(double altitude)
170 double slope, reftemp, refpress;
174 if (altitude < htab[lastIndex]) {
180 while (htab[i] > altitude) i--;
182 } else if (altitude > htab[lastIndex+1]) {
183 if (altitude >= htab[7]) {
188 while (htab[i+1] < altitude) i++;
197 //refdens = 0.000706032;
203 //refdens = 0.000171306;
205 case 3: // 104986 ft.
209 //refdens = 1.18422e-05;
211 case 4: // 154199 ft.
215 //refdens = 4.00585e-7;
217 case 5: // 170603 ft.
221 //refdens = 8.17102e-7;
223 case 6: // 200131 ft.
226 refpress = 0.00684986;
227 //refdens = 8.77702e-9;
229 case 7: // 259186 ft.
232 refpress = 0.000122276;
233 //refdens = 2.19541e-10;
236 default: // sea level
237 slope = -0.00356616; // R/ft.
238 reftemp = 518.67; // R
239 refpress = 2116.22; // psf
240 //refdens = 0.00237767; // slugs/cubic ft.
246 intTemperature = reftemp;
247 intPressure = refpress*exp(-Inertial->SLgravity()/(reftemp*Reng)*(altitude-htab[i]));
248 //intDensity = refdens*exp(-Inertial->SLgravity()/(reftemp*Reng)*(altitude-htab[i]));
249 intDensity = intPressure/(Reng*intTemperature);
251 intTemperature = reftemp+slope*(altitude-htab[i]);
252 intPressure = refpress*pow(intTemperature/reftemp,-Inertial->SLgravity()/(slope*Reng));
253 //intDensity = refdens*pow(intTemperature/reftemp,-(Inertial->SLgravity()/(slope*Reng)+1));
254 intDensity = intPressure/(Reng*intTemperature);
257 //cout << "Atmosphere: h=" << altitude << " rho= " << intDensity << endl;
260 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
262 void FGAtmosphere::Turbulence(void)
266 vDirectiondAccelDt(eX) = 1 - 2.0*(double(rand())/double(RAND_MAX));
267 vDirectiondAccelDt(eY) = 1 - 2.0*(double(rand())/double(RAND_MAX));
268 vDirectiondAccelDt(eZ) = 1 - 2.0*(double(rand())/double(RAND_MAX));
270 MagnitudedAccelDt = 1 - 2.0*(double(rand())/double(RAND_MAX)) - Magnitude;
271 // Scale the magnitude so that it moves
272 // away from the peaks
273 MagnitudedAccelDt = ((MagnitudedAccelDt - Magnitude) /
274 (1 + fabs(Magnitude)));
275 MagnitudeAccel += MagnitudedAccelDt*rate*State->Getdt();
276 Magnitude += MagnitudeAccel*rate*State->Getdt();
278 vDirectiondAccelDt.Normalize();
279 vDirectionAccel += vDirectiondAccelDt*rate*State->Getdt();
280 vDirectionAccel.Normalize();
281 vDirection += vDirectionAccel*rate*State->Getdt();
283 vDirection.Normalize();
285 // Diminish turbulence within three wingspans
287 vTurbulence = TurbGain*Magnitude * vDirection;
288 double HOverBMAC = Position->GetHOverBMAC();
290 vTurbulence *= (HOverBMAC / 3.0) * (HOverBMAC / 3.0);
292 vTurbulenceGrad = TurbGain*MagnitudeAccel * vDirection;
294 vBodyTurbGrad = State->GetTl2b()*vTurbulenceGrad;
295 vTurbPQR(eP) = vBodyTurbGrad(eY)/Aircraft->GetWingSpan();
296 // if (Aircraft->GetHTailArm() != 0.0)
297 // vTurbPQR(eQ) = vBodyTurbGrad(eZ)/Aircraft->GetHTailArm();
299 // vTurbPQR(eQ) = vBodyTurbGrad(eZ)/10.0;
301 if (Aircraft->GetVTailArm())
302 vTurbPQR(eR) = vBodyTurbGrad(eX)/Aircraft->GetVTailArm();
304 vTurbPQR(eR) = vBodyTurbGrad(eX)/10.0;
306 // Clear the horizontal forces
307 // actually felt by the plane, now
308 // that we've used them to calculate
310 vTurbulence(eX) = 0.0;
311 vTurbulence(eY) = 0.0;
316 vDirectiondAccelDt(eX) = 1 - 2.0*(double(rand())/double(RAND_MAX));
317 vDirectiondAccelDt(eY) = 1 - 2.0*(double(rand())/double(RAND_MAX));
318 vDirectiondAccelDt(eZ) = 1 - 2.0*(double(rand())/double(RAND_MAX));
321 MagnitudedAccelDt = 1 - 2.0*(double(rand())/double(RAND_MAX)) - Magnitude;
322 MagnitudeAccel += MagnitudedAccelDt*rate*State->Getdt();
323 Magnitude += MagnitudeAccel*rate*State->Getdt();
325 vDirectiondAccelDt.Normalize();
326 vDirectionAccel += vDirectiondAccelDt*rate*State->Getdt();
327 vDirectionAccel.Normalize();
328 vDirection += vDirectionAccel*rate*State->Getdt();
330 // Diminish z-vector within two wingspans
332 double HOverBMAC = Position->GetHOverBMAC();
334 vDirection(eZ) *= HOverBMAC / 2.0;
336 vDirection.Normalize();
338 vTurbulence = TurbGain*Magnitude * vDirection;
339 vTurbulenceGrad = TurbGain*MagnitudeAccel * vDirection;
341 vBodyTurbGrad = State->GetTl2b()*vTurbulenceGrad;
342 vTurbPQR(eP) = vBodyTurbGrad(eY)/Aircraft->GetWingSpan();
343 if (Aircraft->GetHTailArm() != 0.0)
344 vTurbPQR(eQ) = vBodyTurbGrad(eZ)/Aircraft->GetHTailArm();
346 vTurbPQR(eQ) = vBodyTurbGrad(eZ)/10.0;
348 if (Aircraft->GetVTailArm())
349 vTurbPQR(eR) = vBodyTurbGrad(eX)/Aircraft->GetVTailArm();
351 vTurbPQR(eR) = vBodyTurbGrad(eX)/10.0;
360 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
362 void FGAtmosphere::UseExternal(void) {
363 temperature=&exTemperature;
364 pressure=&exPressure;
369 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
371 void FGAtmosphere::UseInternal(void) {
372 temperature=&intTemperature;
373 pressure=&intPressure;
379 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
381 void FGAtmosphere::bind(void)
383 typedef double (FGAtmosphere::*PMF)(int) const;
384 PropertyManager->Tie("atmosphere/T-R", this,
385 &FGAtmosphere::GetTemperature);
386 PropertyManager->Tie("atmosphere/rho-slugs_ft3", this,
387 &FGAtmosphere::GetDensity);
388 PropertyManager->Tie("atmosphere/P-psf", this,
389 &FGAtmosphere::GetPressure);
390 PropertyManager->Tie("atmosphere/a-fps", this,
391 &FGAtmosphere::GetSoundSpeed);
392 PropertyManager->Tie("atmosphere/T-sl-R", this,
393 &FGAtmosphere::GetTemperatureSL);
394 PropertyManager->Tie("atmosphere/rho-sl-slugs_ft3", this,
395 &FGAtmosphere::GetDensitySL);
396 PropertyManager->Tie("atmosphere/P-sl-psf", this,
397 &FGAtmosphere::GetPressureSL);
398 PropertyManager->Tie("atmosphere/a-sl-fps", this,
399 &FGAtmosphere::GetSoundSpeedSL);
400 PropertyManager->Tie("atmosphere/theta-norm", this,
401 &FGAtmosphere::GetTemperatureRatio);
402 PropertyManager->Tie("atmosphere/sigma-norm", this,
403 &FGAtmosphere::GetDensityRatio);
404 PropertyManager->Tie("atmosphere/delta-norm", this,
405 &FGAtmosphere::GetPressureRatio);
406 PropertyManager->Tie("atmosphere/a-norm", this,
407 &FGAtmosphere::GetSoundSpeedRatio);
408 PropertyManager->Tie("atmosphere/psiw-rad", this,
409 &FGAtmosphere::GetWindPsi);
410 PropertyManager->Tie("atmosphere/p-turb-rad_sec", this,1,
411 (PMF)&FGAtmosphere::GetTurbPQR);
412 PropertyManager->Tie("atmosphere/q-turb-rad_sec", this,2,
413 (PMF)&FGAtmosphere::GetTurbPQR);
414 PropertyManager->Tie("atmosphere/r-turb-rad_sec", this,3,
415 (PMF)&FGAtmosphere::GetTurbPQR);
418 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
420 void FGAtmosphere::unbind(void)
422 PropertyManager->Untie("atmosphere/T-R");
423 PropertyManager->Untie("atmosphere/rho-slugs_ft3");
424 PropertyManager->Untie("atmosphere/P-psf");
425 PropertyManager->Untie("atmosphere/a-fps");
426 PropertyManager->Untie("atmosphere/T-sl-R");
427 PropertyManager->Untie("atmosphere/rho-sl-slugs_ft3");
428 PropertyManager->Untie("atmosphere/P-sl-psf");
429 PropertyManager->Untie("atmosphere/a-sl-fps");
430 PropertyManager->Untie("atmosphere/theta-norm");
431 PropertyManager->Untie("atmosphere/sigma-norm");
432 PropertyManager->Untie("atmosphere/delta-norm");
433 PropertyManager->Untie("atmosphere/a-norm");
434 PropertyManager->Untie("atmosphere/psiw-rad");
435 PropertyManager->Untie("atmosphere/p-turb-rad_sec");
436 PropertyManager->Untie("atmosphere/q-turb-rad_sec");
437 PropertyManager->Untie("atmosphere/r-turb-rad_sec");
440 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
441 // The bitmasked value choices are as follows:
442 // unset: In this case (the default) JSBSim would only print
443 // out the normally expected messages, essentially echoing
444 // the config files as they are read. If the environment
445 // variable is not set, debug_lvl is set to 1 internally
446 // 0: This requests JSBSim not to output any messages
448 // 1: This value explicity requests the normal JSBSim
450 // 2: This value asks for a message to be printed out when
451 // a class is instantiated
452 // 4: When this value is set, a message is displayed when a
453 // FGModel object executes its Run() method
454 // 8: When this value is set, various runtime state variables
455 // are printed out periodically
456 // 16: When set various parameters are sanity checked and
457 // a message is printed out when they go out of bounds
459 void FGAtmosphere::Debug(int from)
461 if (debug_lvl <= 0) return;
463 if (debug_lvl & 1) { // Standard console startup message output
464 if (from == 0) { // Constructor
467 if (debug_lvl & 2 ) { // Instantiation/Destruction notification
468 if (from == 0) cout << "Instantiated: FGAtmosphere" << endl;
469 if (from == 1) cout << "Destroyed: FGAtmosphere" << endl;
471 if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
473 if (debug_lvl & 8 ) { // Runtime state variables
475 if (debug_lvl & 16) { // Sanity checking
477 if (debug_lvl & 32) { // Turbulence
478 if (frame == 0 && from == 2) {
479 cout << "vTurbulence(X), vTurbulence(Y), vTurbulence(Z), "
480 << "vTurbulenceGrad(X), vTurbulenceGrad(Y), vTurbulenceGrad(Z), "
481 << "vDirection(X), vDirection(Y), vDirection(Z), "
483 << "vTurbPQR(P), vTurbPQR(Q), vTurbPQR(R), " << endl;
484 } else if (from == 2) {
485 cout << vTurbulence << ", " << vTurbulenceGrad << ", " << vDirection << ", " << Magnitude << ", " << vTurbPQR << endl;
488 if (debug_lvl & 64) {
489 if (from == 0) { // Constructor
490 cout << IdSrc << endl;
491 cout << IdHdr << endl;
496 } // namespace JSBSim