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;
99 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
101 FGAtmosphere::~FGAtmosphere()
107 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
109 bool FGAtmosphere::InitModel(void)
111 FGModel::InitModel();
114 SLtemperature = intTemperature;
115 SLpressure = intPressure;
116 SLdensity = intDensity;
117 SLsoundspeed = sqrt(SHRatio*Reng*intTemperature);
118 rSLtemperature = 1.0/intTemperature;
119 rSLpressure = 1.0/intPressure;
120 rSLdensity = 1.0/intDensity;
121 rSLsoundspeed = 1.0/SLsoundspeed;
122 temperature=&intTemperature;
123 pressure=&intPressure;
131 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
133 bool FGAtmosphere::Run(void)
135 if (!FGModel::Run()) { // if false then execute this Run()
136 //do temp, pressure, and density first
138 h = Position->Geth();
142 if (turbType != ttNone) {
144 vWindNED += vTurbulence;
147 if (vWindNED(1) != 0.0) psiw = atan2( vWindNED(2), vWindNED(1) );
149 if (psiw < 0) psiw += 2*M_PI;
151 soundspeed = sqrt(SHRatio*Reng*(*temperature));
153 State->Seta(soundspeed);
158 } else { // skip Run() execution this time
163 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
167 void FGAtmosphere::Calculate(double altitude)
169 double slope, reftemp, refpress;
173 if (altitude < htab[lastIndex]) {
179 while (htab[i] > altitude) i--;
181 } else if (altitude > htab[lastIndex+1]) {
182 if (altitude >= htab[7]) {
187 while (htab[i+1] < altitude) i++;
196 //refdens = 0.000706032;
202 //refdens = 0.000171306;
204 case 3: // 104986 ft.
208 //refdens = 1.18422e-05;
210 case 4: // 154199 ft.
214 //refdens = 4.00585e-7;
216 case 5: // 170603 ft.
220 //refdens = 8.17102e-7;
222 case 6: // 200131 ft.
225 refpress = 0.00684986;
226 //refdens = 8.77702e-9;
228 case 7: // 259186 ft.
231 refpress = 0.000122276;
232 //refdens = 2.19541e-10;
235 default: // sea level
236 slope = -0.00356616; // R/ft.
237 reftemp = 518.67; // R
238 refpress = 2116.22; // psf
239 //refdens = 0.00237767; // slugs/cubic ft.
245 intTemperature = reftemp;
246 intPressure = refpress*exp(-Inertial->SLgravity()/(reftemp*Reng)*(altitude-htab[i]));
247 //intDensity = refdens*exp(-Inertial->SLgravity()/(reftemp*Reng)*(altitude-htab[i]));
248 intDensity = intPressure/(Reng*intTemperature);
250 intTemperature = reftemp+slope*(altitude-htab[i]);
251 intPressure = refpress*pow(intTemperature/reftemp,-Inertial->SLgravity()/(slope*Reng));
252 //intDensity = refdens*pow(intTemperature/reftemp,-(Inertial->SLgravity()/(slope*Reng)+1));
253 intDensity = intPressure/(Reng*intTemperature);
256 //cout << "Atmosphere: h=" << altitude << " rho= " << intDensity << endl;
259 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
261 void FGAtmosphere::Turbulence(void)
265 vDirectiondAccelDt(eX) = 1 - 2.0*(((double)(rand()))/RAND_MAX);
266 vDirectiondAccelDt(eY) = 1 - 2.0*(((double)(rand()))/RAND_MAX);
267 vDirectiondAccelDt(eZ) = 1 - 2.0*(((double)(rand()))/RAND_MAX);
270 MagnitudedAccelDt = 1 - 2.0*(((double)(rand()))/RAND_MAX) - Magnitude;
271 MagnitudeAccel += MagnitudedAccelDt*rate*State->Getdt();
272 Magnitude += MagnitudeAccel*rate*State->Getdt();
274 // Fade the magnitude within two wingspans
275 // of the ground (WAG)
276 double AdjustedMagnitude = Magnitude;
277 double AdjustedMagnitudeAccel = MagnitudeAccel;
278 double HOverBMAC = Position->GetHOverBMAC();
279 if (HOverBMAC < 2.0) {
280 AdjustedMagnitude *= (HOverBMAC / 2.0);
281 AdjustedMagnitudeAccel *= (HOverBMAC / 2.0);
284 vDirectiondAccelDt.Normalize();
285 vDirectionAccel += vDirectiondAccelDt*rate*State->Getdt();
286 vDirectionAccel.Normalize();
287 vDirection += vDirectionAccel*rate*State->Getdt();
288 vDirection.Normalize();
290 vTurbulence = TurbGain*AdjustedMagnitude * vDirection;
291 vTurbulenceGrad = TurbGain*AdjustedMagnitudeAccel * vDirection;
293 vBodyTurbGrad = State->GetTl2b()*vTurbulenceGrad;
294 vTurbPQR(eP) = vBodyTurbGrad(eY)/Aircraft->GetWingSpan();
295 if (Aircraft->GetHTailArm() != 0.0)
296 vTurbPQR(eQ) = vBodyTurbGrad(eZ)/Aircraft->GetHTailArm();
298 vTurbPQR(eQ) = vBodyTurbGrad(eZ)/10.0;
300 if (Aircraft->GetVTailArm())
301 vTurbPQR(eR) = vBodyTurbGrad(eX)/Aircraft->GetVTailArm();
303 vTurbPQR(eR) = vBodyTurbGrad(eX)/10.0;
312 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
314 void FGAtmosphere::UseExternal(void) {
315 temperature=&exTemperature;
316 pressure=&exPressure;
321 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
323 void FGAtmosphere::UseInternal(void) {
324 temperature=&intTemperature;
325 pressure=&intPressure;
331 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
333 void FGAtmosphere::bind(void)
335 typedef double (FGAtmosphere::*PMF)(int) const;
336 PropertyManager->Tie("atmosphere/T-R", this,
337 &FGAtmosphere::GetTemperature);
338 PropertyManager->Tie("atmosphere/rho-slugs_ft3", this,
339 &FGAtmosphere::GetDensity);
340 PropertyManager->Tie("atmosphere/P-psf", this,
341 &FGAtmosphere::GetPressure);
342 PropertyManager->Tie("atmosphere/a-fps", this,
343 &FGAtmosphere::GetSoundSpeed);
344 PropertyManager->Tie("atmosphere/T-sl-R", this,
345 &FGAtmosphere::GetTemperatureSL);
346 PropertyManager->Tie("atmosphere/rho-sl-slugs_ft3", this,
347 &FGAtmosphere::GetDensitySL);
348 PropertyManager->Tie("atmosphere/P-sl-psf", this,
349 &FGAtmosphere::GetPressureSL);
350 PropertyManager->Tie("atmosphere/a-sl-fps", this,
351 &FGAtmosphere::GetSoundSpeedSL);
352 PropertyManager->Tie("atmosphere/theta-norm", this,
353 &FGAtmosphere::GetTemperatureRatio);
354 PropertyManager->Tie("atmosphere/sigma-norm", this,
355 &FGAtmosphere::GetDensityRatio);
356 PropertyManager->Tie("atmosphere/delta-norm", this,
357 &FGAtmosphere::GetPressureRatio);
358 PropertyManager->Tie("atmosphere/a-norm", this,
359 &FGAtmosphere::GetSoundSpeedRatio);
360 PropertyManager->Tie("atmosphere/psiw-rad", this,
361 &FGAtmosphere::GetWindPsi);
362 PropertyManager->Tie("atmosphere/p-turb-rad_sec", this,1,
363 (PMF)&FGAtmosphere::GetTurbPQR);
364 PropertyManager->Tie("atmosphere/q-turb-rad_sec", this,2,
365 (PMF)&FGAtmosphere::GetTurbPQR);
366 PropertyManager->Tie("atmosphere/r-turb-rad_sec", this,3,
367 (PMF)&FGAtmosphere::GetTurbPQR);
370 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
372 void FGAtmosphere::unbind(void)
374 PropertyManager->Untie("atmosphere/T-R");
375 PropertyManager->Untie("atmosphere/rho-slugs_ft3");
376 PropertyManager->Untie("atmosphere/P-psf");
377 PropertyManager->Untie("atmosphere/a-fps");
378 PropertyManager->Untie("atmosphere/T-sl-R");
379 PropertyManager->Untie("atmosphere/rho-sl-slugs_ft3");
380 PropertyManager->Untie("atmosphere/P-sl-psf");
381 PropertyManager->Untie("atmosphere/a-sl-fps");
382 PropertyManager->Untie("atmosphere/theta-norm");
383 PropertyManager->Untie("atmosphere/sigma-norm");
384 PropertyManager->Untie("atmosphere/delta-norm");
385 PropertyManager->Untie("atmosphere/a-norm");
386 PropertyManager->Untie("atmosphere/psiw-rad");
387 PropertyManager->Untie("atmosphere/p-turb-rad_sec");
388 PropertyManager->Untie("atmosphere/q-turb-rad_sec");
389 PropertyManager->Untie("atmosphere/r-turb-rad_sec");
392 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
393 // The bitmasked value choices are as follows:
394 // unset: In this case (the default) JSBSim would only print
395 // out the normally expected messages, essentially echoing
396 // the config files as they are read. If the environment
397 // variable is not set, debug_lvl is set to 1 internally
398 // 0: This requests JSBSim not to output any messages
400 // 1: This value explicity requests the normal JSBSim
402 // 2: This value asks for a message to be printed out when
403 // a class is instantiated
404 // 4: When this value is set, a message is displayed when a
405 // FGModel object executes its Run() method
406 // 8: When this value is set, various runtime state variables
407 // are printed out periodically
408 // 16: When set various parameters are sanity checked and
409 // a message is printed out when they go out of bounds
411 void FGAtmosphere::Debug(int from)
413 if (debug_lvl <= 0) return;
415 if (debug_lvl & 1) { // Standard console startup message output
416 if (from == 0) { // Constructor
419 if (debug_lvl & 2 ) { // Instantiation/Destruction notification
420 if (from == 0) cout << "Instantiated: FGAtmosphere" << endl;
421 if (from == 1) cout << "Destroyed: FGAtmosphere" << endl;
423 if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
425 if (debug_lvl & 8 ) { // Runtime state variables
427 if (debug_lvl & 16) { // Sanity checking
429 if (debug_lvl & 32) { // Turbulence
430 if (frame == 0 && from == 2) {
431 cout << "vTurbulence(X), vTurbulence(Y), vTurbulence(Z), "
432 << "vTurbulenceGrad(X), vTurbulenceGrad(Y), vTurbulenceGrad(Z), "
433 << "vDirection(X), vDirection(Y), vDirection(Z), "
435 << "vTurbPQR(P), vTurbPQR(Q), vTurbPQR(R), " << endl;
436 } else if (from == 2) {
437 cout << vTurbulence << ", " << vTurbulenceGrad << ", " << vDirection << ", " << Magnitude << ", " << vTurbPQR << endl;
440 if (debug_lvl & 64) {
441 if (from == 0) { // Constructor
442 cout << IdSrc << endl;
443 cout << IdHdr << endl;
448 } // namespace JSBSim