src/FDM/JSBSim/models/FGAtmosphere.cpp

   1 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   2
   3  Module:       FGAtmosphere.cpp
   4  Author:       Jon Berndt
   5                Implementation of 1959 Standard Atmosphere added by Tony Peden
   6  Date started: 11/24/98
   7  Purpose:      Models the atmosphere
   8  Called by:    FGSimExec
   9
  10  ------------- Copyright (C) 1999  Jon S. Berndt (jsb@hal-pc.org) -------------
  11
  12  This program is free software; you can redistribute it and/or modify it under
  13  the terms of the GNU Lesser General Public License as published by the Free Software
  14  Foundation; either version 2 of the License, or (at your option) any later
  15  version.
  16
  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 Lesser General Public License for more
  20  details.
  21
  22  You should have received a copy of the GNU Lesser 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.
  25
  26  Further information about the GNU Lesser General Public License can also be found on
  27  the world wide web at http://www.gnu.org.
  28
  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.
  33
  34 HISTORY
  35 --------------------------------------------------------------------------------
  36 11/24/98   JSB   Created
  37 07/23/99   TP    Added implementation of 1959 Standard Atmosphere
  38                  Moved calculation of Mach number to FGPropagate
  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
  45
  46 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  47 INCLUDES
  48 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  49
  50 #include "FGAtmosphere.h"
  51 #include <FGState.h>
  52 #include <FGFDMExec.h>
  53 #include "FGAircraft.h"
  54 #include "FGPropagate.h"
  55 #include "FGInertial.h"
  56 #include <input_output/FGPropertyManager.h>
  57
  58 namespace JSBSim {
  59
  60 static const char *IdSrc = "$Id$";
  61 static const char *IdHdr = ID_ATMOSPHERE;
  62
  63 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  64 CLASS IMPLEMENTATION
  65 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  66
  67 FGAtmosphere::FGAtmosphere(FGFDMExec* fdmex) : FGModel(fdmex)
  68 {
  69   Name = "FGAtmosphere";
  70   lastIndex = 0;
  71   h = 0.0;
  72   psiw = 0.0;
  73   htab[0]=0;
  74   htab[1]= 36089.0;
  75   htab[2]= 65617.0;
  76   htab[3]=104987.0;
  77   htab[4]=154199.0;
  78   htab[5]=167322.0;
  79   htab[6]=232940.0;
  80   htab[7]=278385.0; //ft.
  81
  82   MagnitudedAccelDt = MagnitudeAccel = Magnitude = 0.0;
  83   SetTurbType( ttCulp );
  84   TurbGain = 0.0;
  85   TurbRate = 1.7;
  86   Rhythmicity = 0.1;
  87   spike = target_time = strength = 0.0;
  88   wind_from_clockwise = 0.0;
  89   SutherlandConstant = 198.72; // deg Rankine
  90   Beta = 2.269690E-08; // slug/(sec ft R^0.5)
  91
  92   T_dev_sl = T_dev = delta_T = 0.0;
  93   StandardTempOnly = false;
  94   first_pass = true;
  95   vGustNED.InitMatrix();
  96   vTurbulenceNED.InitMatrix();
  97
  98   bind();
  99   Debug(0);
 100 }
 101
 102 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 103
 104 FGAtmosphere::~FGAtmosphere()
 105 {
 106   Debug(1);
 107 }
 108
 109 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 110
 111 bool FGAtmosphere::InitModel(void)
 112 {
 113   if (!FGModel::InitModel()) return false;
 114
 115   UseInternal();  // this is the default
 116
 117   Calculate(h);
 118   StdSLtemperature = SLtemperature = 518.67;
 119   StdSLpressure    = SLpressure = 2116.22;
 120   StdSLdensity     = SLdensity = 0.00237767;
 121   StdSLsoundspeed  = SLsoundspeed = sqrt(SHRatio*Reng*StdSLtemperature);
 122   rSLtemperature = 1.0/StdSLtemperature;
 123   rSLpressure    = 1.0/StdSLpressure;
 124   rSLdensity     = 1.0/StdSLdensity;
 125   rSLsoundspeed  = 1.0/StdSLsoundspeed;
 126
 127   return true;
 128 }
 129
 130 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 131
 132 bool FGAtmosphere::Run(void)
 133 {
 134   if (FGModel::Run()) return true;
 135   if (FDMExec->Holding()) return false;
 136
 137   T_dev = 0.0;
 138   h = Propagate->Geth();
 139
 140   if (!useExternal) {
 141     Calculate(h);
 142     CalculateDerived();
 143   } else {
 144     CalculateDerived();
 145   }
 146
 147   Debug(2);
 148   return false;
 149 }
 150
 151 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 152 //
 153 // See reference 1
 154
 155 void FGAtmosphere::Calculate(double altitude)
 156 {
 157   double slope, reftemp, refpress;
 158   int i = lastIndex;
 159
 160   if (altitude < htab[lastIndex]) {
 161     if (altitude <= 0) {
 162       i = 0;
 163       altitude=0;
 164     } else {
 165        i = lastIndex-1;
 166        while (htab[i] > altitude) i--;
 167     }
 168   } else if (altitude > htab[lastIndex+1]) {
 169     if (altitude >= htab[7]) {
 170       i = 7;
 171       altitude = htab[7];
 172     } else {
 173       i = lastIndex+1;
 174       while (htab[i+1] < altitude) i++;
 175     }
 176   }
 177
 178   switch(i) {
 179   case 0: // Sea level
 180     slope     = -0.00356616; // R/ft.
 181     reftemp   = 518.67;   // in degrees Rankine, 288.15 Kelvin
 182     refpress  = 2116.22;    // psf
 183     //refdens   = 0.00237767;  // slugs/cubic ft.
 184     break;
 185   case 1:     // 36089 ft. or 11 km
 186     slope     = 0;
 187     reftemp   = 389.97; // in degrees Rankine, 216.65 Kelvin
 188     refpress  = 472.763;
 189     //refdens   = 0.000706032;
 190     break;
 191   case 2:     // 65616 ft. or 20 km
 192     slope     = 0.00054864;
 193     reftemp   = 389.97; // in degrees Rankine, 216.65 Kelvin
 194     refpress  = 114.636;
 195     //refdens   = 0.000171306;
 196     break;
 197   case 3:     // 104986 ft. or 32 km
 198     slope     = 0.001536192;
 199     reftemp   = 411.57; // in degrees Rankine, 228.65 Kelvin
 200     refpress  = 18.128;
 201     //refdens   = 1.18422e-05;
 202     break;
 203   case 4:     // 154199 ft. 47 km
 204     slope     = 0;
 205     reftemp   = 487.17; // in degrees Rankine, 270.65 Kelvin
 206     refpress  = 2.316;
 207     //refdens   = 4.00585e-7;
 208     break;
 209   case 5:     // 167322 ft. or 51 km
 210     slope     = -0.001536192;
 211     reftemp   = 487.17; // in degrees Rankine, 270.65 Kelvin
 212     refpress  = 1.398;
 213     //refdens   = 8.17102e-7;
 214     break;
 215   case 6:     // 232940 ft. or 71 km
 216     slope     = -0.00109728;
 217     reftemp   = 386.368; // in degrees Rankine, 214.649 Kelvin
 218     refpress  = 0.0826;
 219     //refdens   = 8.77702e-9;
 220     break;
 221   case 7:     // 278385 ft. or 84.8520 km
 222     slope     = 0;
 223     reftemp   = 336.5; // in degrees Rankine, 186.94 Kelvin
 224     refpress  = 0.00831;
 225     //refdens   = 2.19541e-10;
 226     break;
 227   default:     // sea level
 228     slope     = -0.00356616; // R/ft.
 229     reftemp   = 518.67;   // in degrees Rankine, 288.15 Kelvin
 230     refpress  = 2116.22;    // psf
 231     //refdens   = 0.00237767;  // slugs/cubic ft.
 232     break;
 233
 234   }
 235
 236   // If delta_T is set, then that is our temperature deviation at any altitude.
 237   // If not, then we'll estimate a deviation based on the sea level deviation (if set).
 238
 239   if(!StandardTempOnly) {
 240     T_dev = 0.0;
 241     if (delta_T != 0.0) {
 242       T_dev = delta_T;
 243     } else {
 244       if ((altitude < 36089.239) && (T_dev_sl != 0.0)) {
 245         T_dev = T_dev_sl * ( 1.0 - (altitude/36089.239));
 246       }
 247     }
 248     reftemp+=T_dev;
 249   }
 250
 251   if (slope == 0) {
 252     intTemperature = reftemp;
 253     intPressure = refpress*exp(-Inertial->SLgravity()/(reftemp*Reng)*(altitude-htab[i]));
 254     intDensity = intPressure/(Reng*intTemperature);
 255   } else {
 256     intTemperature = reftemp+slope*(altitude-htab[i]);
 257     intPressure = refpress*pow(intTemperature/reftemp,-Inertial->SLgravity()/(slope*Reng));
 258     intDensity = intPressure/(Reng*intTemperature);
 259   }
 260
 261   lastIndex=i;
 262 }
 263
 264 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 265 // Calculate parameters derived from T, P and rho
 266 // Sum gust and turbulence values in NED frame into the wind vector.
 267
 268 void FGAtmosphere::CalculateDerived(void)
 269 {
 270   T_dev = (*temperature) - GetTemperature(h);
 271   density_altitude = h + T_dev * 66.7;
 272
 273   if (turbType != ttNone) Turbulence();
 274
 275   vTotalWindNED = vWindNED + vGustNED + vTurbulenceNED;
 276
 277   if (vWindNED(eX) != 0.0) psiw = atan2( vWindNED(eY), vWindNED(eX) );
 278   if (psiw < 0) psiw += 2*M_PI;
 279
 280   soundspeed = sqrt(SHRatio*Reng*(*temperature));
 281
 282   intViscosity = Beta * pow(intTemperature, 1.5) / (SutherlandConstant + intTemperature);
 283   intKinematicViscosity = intViscosity / intDensity;
 284 }
 285
 286
 287 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 288 // Get the standard atmospheric properties at a specified altitude
 289
 290 void FGAtmosphere::GetStdAtmosphere(double altitude) {
 291   StandardTempOnly = true;
 292   Calculate(altitude);
 293   StandardTempOnly = false;
 294   atmosphere.Temperature = intTemperature;
 295   atmosphere.Pressure = intPressure;
 296   atmosphere.Density = intDensity;
 297
 298   // Reset the internal atmospheric state
 299   Calculate(h);
 300 }
 301
 302 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 303 // Get the standard pressure at a specified altitude
 304
 305 double FGAtmosphere::GetPressure(double altitude) {
 306   GetStdAtmosphere(altitude);
 307   return atmosphere.Pressure;
 308 }
 309
 310 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 311 // Get the standard temperature at a specified altitude
 312
 313 double FGAtmosphere::GetTemperature(double altitude) {
 314   GetStdAtmosphere(altitude);
 315   return atmosphere.Temperature;
 316 }
 317
 318 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 319 // Get the standard density at a specified altitude
 320
 321 double FGAtmosphere::GetDensity(double altitude) {
 322   GetStdAtmosphere(altitude);
 323   return atmosphere.Density;
 324 }
 325
 326
 327 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 328 // square a value, but preserve the original sign
 329
 330 static inline double square_signed (double value)
 331 {
 332     if (value < 0)
 333         return value * value * -1;
 334     else
 335         return value * value;
 336 }
 337
 338 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 339
 340 void FGAtmosphere::SetWindspeed(double speed)
 341 {
 342   if (vWindNED.Magnitude() == 0.0) {
 343     psiw = 0.0;
 344     vWindNED(eNorth) = speed;
 345   } else {
 346     vWindNED(eNorth) = speed * cos(psiw);
 347     vWindNED(eEast) = speed * sin(psiw);
 348     vWindNED(eDown) = 0.0;
 349   }
 350 }
 351
 352 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 353
 354 double FGAtmosphere::GetWindspeed(void) const
 355 {
 356   return vWindNED.Magnitude();
 357 }
 358
 359 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 360
 361 void FGAtmosphere::SetWindPsi(double dir)
 362 {
 363   double mag = GetWindspeed();
 364   psiw = dir;
 365   SetWindspeed(mag);
 366 }
 367
 368 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 369
 370 void FGAtmosphere::Turbulence(void)
 371 {
 372   switch (turbType) {
 373   case ttStandard: {
 374     TurbGain = TurbGain * TurbGain * 100.0;
 375
 376     vDirectiondAccelDt(eX) = 1 - 2.0*(double(rand())/double(RAND_MAX));
 377     vDirectiondAccelDt(eY) = 1 - 2.0*(double(rand())/double(RAND_MAX));
 378     vDirectiondAccelDt(eZ) = 1 - 2.0*(double(rand())/double(RAND_MAX));
 379
 380     MagnitudedAccelDt = 1 - 2.0*(double(rand())/double(RAND_MAX)) - Magnitude;
 381                                 // Scale the magnitude so that it moves
 382                                 // away from the peaks
 383     MagnitudedAccelDt = ((MagnitudedAccelDt - Magnitude) /
 384                          (1 + fabs(Magnitude)));
 385     MagnitudeAccel    += MagnitudedAccelDt*rate*TurbRate*State->Getdt();
 386     Magnitude         += MagnitudeAccel*rate*State->Getdt();
 387     Magnitude          = fabs(Magnitude);
 388
 389     vDirectiondAccelDt.Normalize();
 390
 391                                 // deemphasise non-vertical forces
 392     vDirectiondAccelDt(eX) = square_signed(vDirectiondAccelDt(eX));
 393     vDirectiondAccelDt(eY) = square_signed(vDirectiondAccelDt(eY));
 394
 395     vDirectionAccel += vDirectiondAccelDt*rate*TurbRate*State->Getdt();
 396     vDirectionAccel.Normalize();
 397     vDirection      += vDirectionAccel*rate*State->Getdt();
 398
 399     vDirection.Normalize();
 400
 401                                 // Diminish turbulence within three wingspans
 402                                 // of the ground
 403     vTurbulenceNED = TurbGain * Magnitude * vDirection;
 404     double HOverBMAC = Auxiliary->GetHOverBMAC();
 405     if (HOverBMAC < 3.0)
 406         vTurbulenceNED *= (HOverBMAC / 3.0) * (HOverBMAC / 3.0);
 407
 408     // I don't believe these next two statements calculate the proper gradient over
 409     // the aircraft body. One reason is because this has no relationship with the
 410     // orientation or velocity of the aircraft, which it must have. What is vTurbulenceGrad
 411     // supposed to represent? And the direction and magnitude of the turbulence can change,
 412     // so both accelerations need to be accounted for, no?
 413
 414     // Need to determine the turbulence change in body axes between two time points.
 415
 416     vTurbulenceGrad = TurbGain*MagnitudeAccel * vDirection;
 417     vBodyTurbGrad = Propagate->GetTl2b()*vTurbulenceGrad;
 418
 419     if (Aircraft->GetWingSpan() > 0) {
 420       vTurbPQR(eP) = vBodyTurbGrad(eY)/Aircraft->GetWingSpan();
 421     } else {
 422       vTurbPQR(eP) = vBodyTurbGrad(eY)/30.0;
 423     }
 424 //     if (Aircraft->GetHTailArm() != 0.0)
 425 //       vTurbPQR(eQ) = vBodyTurbGrad(eZ)/Aircraft->GetHTailArm();
 426 //     else
 427 //       vTurbPQR(eQ) = vBodyTurbGrad(eZ)/10.0;
 428
 429     if (Aircraft->GetVTailArm() > 0)
 430       vTurbPQR(eR) = vBodyTurbGrad(eX)/Aircraft->GetVTailArm();
 431     else
 432       vTurbPQR(eR) = vBodyTurbGrad(eX)/10.0;
 433
 434                                 // Clear the horizontal forces
 435                                 // actually felt by the plane, now
 436                                 // that we've used them to calculate
 437                                 // moments.
 438                                 // Why? (JSB)
 439 //    vTurbulenceNED(eX) = 0.0;
 440 //    vTurbulenceNED(eY) = 0.0;
 441
 442     break;
 443   }
 444   case ttBerndt: { // This is very experimental and incomplete at the moment.
 445
 446     TurbGain = TurbGain * TurbGain * 100.0;
 447
 448     vDirectiondAccelDt(eX) = 1 - 2.0*(double(rand())/double(RAND_MAX));
 449     vDirectiondAccelDt(eY) = 1 - 2.0*(double(rand())/double(RAND_MAX));
 450     vDirectiondAccelDt(eZ) = 1 - 2.0*(double(rand())/double(RAND_MAX));
 451
 452
 453     MagnitudedAccelDt = 1 - 2.0*(double(rand())/double(RAND_MAX)) - Magnitude;
 454     MagnitudeAccel    += MagnitudedAccelDt*rate*State->Getdt();
 455     Magnitude         += MagnitudeAccel*rate*State->Getdt();
 456
 457     vDirectiondAccelDt.Normalize();
 458     vDirectionAccel += vDirectiondAccelDt*rate*State->Getdt();
 459     vDirectionAccel.Normalize();
 460     vDirection      += vDirectionAccel*rate*State->Getdt();
 461
 462                                 // Diminish z-vector within two wingspans
 463                                 // of the ground
 464     double HOverBMAC = Auxiliary->GetHOverBMAC();
 465     if (HOverBMAC < 2.0)
 466         vDirection(eZ) *= HOverBMAC / 2.0;
 467
 468     vDirection.Normalize();
 469
 470     vTurbulenceNED = TurbGain*Magnitude * vDirection;
 471     vTurbulenceGrad = TurbGain*MagnitudeAccel * vDirection;
 472
 473     vBodyTurbGrad = Propagate->GetTl2b()*vTurbulenceGrad;
 474     vTurbPQR(eP) = vBodyTurbGrad(eY)/Aircraft->GetWingSpan();
 475     if (Aircraft->GetHTailArm() > 0)
 476       vTurbPQR(eQ) = vBodyTurbGrad(eZ)/Aircraft->GetHTailArm();
 477     else
 478       vTurbPQR(eQ) = vBodyTurbGrad(eZ)/10.0;
 479
 480     if (Aircraft->GetVTailArm() > 0)
 481       vTurbPQR(eR) = vBodyTurbGrad(eX)/Aircraft->GetVTailArm();
 482     else
 483       vTurbPQR(eR) = vBodyTurbGrad(eX)/10.0;
 484
 485     break;
 486   }
 487   case ttCulp: {
 488
 489     vTurbPQR(eP) = wind_from_clockwise;
 490     if (TurbGain == 0.0) return;
 491
 492     // keep the inputs within allowable limts for this model
 493     if (TurbGain < 0.0) TurbGain = 0.0;
 494     if (TurbGain > 1.0) TurbGain = 1.0;
 495     if (TurbRate < 0.0) TurbRate = 0.0;
 496     if (TurbRate > 30.0) TurbRate = 30.0;
 497     if (Rhythmicity < 0.0) Rhythmicity = 0.0;
 498     if (Rhythmicity > 1.0) Rhythmicity = 1.0;
 499
 500     // generate a sine wave corresponding to turbulence rate in hertz
 501     double time = FDMExec->GetSimTime();
 502     double sinewave = sin( time * TurbRate * 6.283185307 );
 503
 504     double random = 0.0;
 505     if (target_time == 0.0) {
 506       strength = random = 1 - 2.0*(double(rand())/double(RAND_MAX));
 507       target_time = time + 0.71 + (random * 0.5);
 508     }
 509     if (time > target_time) {
 510       spike = 1.0;
 511       target_time = 0.0;
 512     }
 513
 514     // max vertical wind speed in fps, corresponds to TurbGain = 1.0
 515     double max_vs = 40;
 516
 517     vTurbulenceNED(1) = vTurbulenceNED(2) = vTurbulenceNED(3) = 0.0;
 518     double delta = strength * max_vs * TurbGain * (1-Rhythmicity) * spike;
 519
 520     // Vertical component of turbulence.
 521     vTurbulenceNED(3) = sinewave * max_vs * TurbGain * Rhythmicity;
 522     vTurbulenceNED(3)+= delta;
 523     double HOverBMAC = Auxiliary->GetHOverBMAC();
 524     if (HOverBMAC < 3.0)
 525         vTurbulenceNED(3) *= HOverBMAC * 0.3333;
 526
 527     // Yaw component of turbulence.
 528     vTurbulenceNED(1) = sin( delta * 3.0 );
 529     vTurbulenceNED(2) = cos( delta * 3.0 );
 530
 531     // Roll component of turbulence. Clockwise vortex causes left roll.
 532     vTurbPQR(eP) += delta * 0.04;
 533
 534     spike = spike * 0.9;
 535     break;
 536   }
 537   default:
 538     break;
 539   }
 540 }
 541
 542 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 543
 544 void FGAtmosphere::UseExternal(void)
 545 {
 546   temperature=&exTemperature;
 547   pressure=&exPressure;
 548   density=&exDensity;
 549   useExternal=true;
 550 }
 551
 552 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 553
 554 void FGAtmosphere::UseInternal(void)
 555 {
 556   temperature=&intTemperature;
 557   pressure=&intPressure;
 558   density=&intDensity;
 559   useExternal=false;
 560 }
 561
 562 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 563
 564 void FGAtmosphere::bind(void)
 565 {
 566   typedef double (FGAtmosphere::*PMF)(int) const;
 567   typedef double (FGAtmosphere::*PMFv)(void) const;
 568   typedef void   (FGAtmosphere::*PMFd)(int,double);
 569   PropertyManager->Tie("atmosphere/T-R", this, (PMFv)&FGAtmosphere::GetTemperature);
 570   PropertyManager->Tie("atmosphere/rho-slugs_ft3", this, (PMFv)&FGAtmosphere::GetDensity);
 571   PropertyManager->Tie("atmosphere/P-psf", this, (PMFv)&FGAtmosphere::GetPressure);
 572   PropertyManager->Tie("atmosphere/a-fps", this, &FGAtmosphere::GetSoundSpeed);
 573   PropertyManager->Tie("atmosphere/T-sl-R", this, &FGAtmosphere::GetTemperatureSL);
 574   PropertyManager->Tie("atmosphere/rho-sl-slugs_ft3", this, &FGAtmosphere::GetDensitySL);
 575   PropertyManager->Tie("atmosphere/P-sl-psf", this, &FGAtmosphere::GetPressureSL);
 576   PropertyManager->Tie("atmosphere/a-sl-fps", this, &FGAtmosphere::GetSoundSpeedSL);
 577   PropertyManager->Tie("atmosphere/theta", this, &FGAtmosphere::GetTemperatureRatio);
 578   PropertyManager->Tie("atmosphere/sigma", this, &FGAtmosphere::GetDensityRatio);
 579   PropertyManager->Tie("atmosphere/delta", this, &FGAtmosphere::GetPressureRatio);
 580   PropertyManager->Tie("atmosphere/a-ratio", this, &FGAtmosphere::GetSoundSpeedRatio);
 581   PropertyManager->Tie("atmosphere/psiw-rad", this, &FGAtmosphere::GetWindPsi);
 582   PropertyManager->Tie("atmosphere/delta-T", this, &FGAtmosphere::GetDeltaT, &FGAtmosphere::SetDeltaT);
 583   PropertyManager->Tie("atmosphere/T-sl-dev-F", this, &FGAtmosphere::GetSLTempDev, &FGAtmosphere::SetSLTempDev);
 584   PropertyManager->Tie("atmosphere/density-altitude", this, &FGAtmosphere::GetDensityAltitude);
 585
 586   PropertyManager->Tie("atmosphere/wind-north-fps", this, eNorth, (PMF)&FGAtmosphere::GetWindNED,
 587                                                           (PMFd)&FGAtmosphere::SetWindNED);
 588   PropertyManager->Tie("atmosphere/wind-east-fps",  this, eEast, (PMF)&FGAtmosphere::GetWindNED,
 589                                                           (PMFd)&FGAtmosphere::SetWindNED);
 590   PropertyManager->Tie("atmosphere/wind-down-fps",  this, eDown, (PMF)&FGAtmosphere::GetWindNED,
 591                                                           (PMFd)&FGAtmosphere::SetWindNED);
 592   PropertyManager->Tie("atmosphere/wind-from-cw", this, &FGAtmosphere::GetWindFromClockwise,
 593                                                         &FGAtmosphere::SetWindFromClockwise);
 594   PropertyManager->Tie("atmosphere/wind-mag-fps", this, &FGAtmosphere::GetWindspeed,
 595                                                         &FGAtmosphere::SetWindspeed);
 596   PropertyManager->Tie("atmosphere/total-wind-north-fps", this, eNorth, (PMF)&FGAtmosphere::GetTotalWindNED);
 597   PropertyManager->Tie("atmosphere/total-wind-east-fps",  this, eEast,  (PMF)&FGAtmosphere::GetTotalWindNED);
 598   PropertyManager->Tie("atmosphere/total-wind-down-fps",  this, eDown,  (PMF)&FGAtmosphere::GetTotalWindNED);
 599
 600   PropertyManager->Tie("atmosphere/gust-north-fps", this, eNorth, (PMF)&FGAtmosphere::GetGustNED,
 601                                                           (PMFd)&FGAtmosphere::SetGustNED);
 602   PropertyManager->Tie("atmosphere/gust-east-fps",  this, eEast, (PMF)&FGAtmosphere::GetGustNED,
 603                                                           (PMFd)&FGAtmosphere::SetGustNED);
 604   PropertyManager->Tie("atmosphere/gust-down-fps",  this, eDown, (PMF)&FGAtmosphere::GetGustNED,
 605                                                           (PMFd)&FGAtmosphere::SetGustNED);
 606
 607   PropertyManager->Tie("atmosphere/p-turb-rad_sec", this,1, (PMF)&FGAtmosphere::GetTurbPQR);
 608   PropertyManager->Tie("atmosphere/q-turb-rad_sec", this,2, (PMF)&FGAtmosphere::GetTurbPQR);
 609   PropertyManager->Tie("atmosphere/r-turb-rad_sec", this,3, (PMF)&FGAtmosphere::GetTurbPQR);
 610   PropertyManager->Tie("atmosphere/turb-rate", this, &FGAtmosphere::GetTurbRate, &FGAtmosphere::SetTurbRate);
 611   PropertyManager->Tie("atmosphere/turb-gain", this, &FGAtmosphere::GetTurbGain, &FGAtmosphere::SetTurbGain);
 612   PropertyManager->Tie("atmosphere/turb-rhythmicity", this, &FGAtmosphere::GetRhythmicity,
 613                                                             &FGAtmosphere::SetRhythmicity);
 614 }
 615
 616 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 617 //    The bitmasked value choices are as follows:
 618 //    unset: In this case (the default) JSBSim would only print
 619 //       out the normally expected messages, essentially echoing
 620 //       the config files as they are read. If the environment
 621 //       variable is not set, debug_lvl is set to 1 internally
 622 //    0: This requests JSBSim not to output any messages
 623 //       whatsoever.
 624 //    1: This value explicity requests the normal JSBSim
 625 //       startup messages
 626 //    2: This value asks for a message to be printed out when
 627 //       a class is instantiated
 628 //    4: When this value is set, a message is displayed when a
 629 //       FGModel object executes its Run() method
 630 //    8: When this value is set, various runtime state variables
 631 //       are printed out periodically
 632 //    16: When set various parameters are sanity checked and
 633 //       a message is printed out when they go out of bounds
 634
 635 void FGAtmosphere::Debug(int from)
 636 {
 637   if (debug_lvl <= 0) return;
 638
 639   if (debug_lvl & 1) { // Standard console startup message output
 640     if (from == 0) { // Constructor
 641     }
 642   }
 643   if (debug_lvl & 2 ) { // Instantiation/Destruction notification
 644     if (from == 0) cout << "Instantiated: FGAtmosphere" << endl;
 645     if (from == 1) cout << "Destroyed:    FGAtmosphere" << endl;
 646   }
 647   if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
 648   }
 649   if (debug_lvl & 8 ) { // Runtime state variables
 650   }
 651   if (debug_lvl & 16) { // Sanity checking
 652   }
 653   if (debug_lvl & 128) { // Turbulence
 654     if (first_pass && from == 2) {
 655       first_pass = false;
 656       cout << "vTurbulenceNED(X), vTurbulenceNED(Y), vTurbulenceNED(Z), "
 657            << "vTurbulenceGrad(X), vTurbulenceGrad(Y), vTurbulenceGrad(Z), "
 658            << "vDirection(X), vDirection(Y), vDirection(Z), "
 659            << "Magnitude, "
 660            << "vTurbPQR(P), vTurbPQR(Q), vTurbPQR(R), " << endl;
 661     }
 662     if (from == 2) {
 663       cout << vTurbulenceNED << ", " << vTurbulenceGrad << ", " << vDirection << ", " << Magnitude << ", " << vTurbPQR << endl;
 664     }
 665   }
 666   if (debug_lvl & 64) {
 667     if (from == 0) { // Constructor
 668       cout << IdSrc << endl;
 669       cout << IdHdr << endl;
 670     }
 671   }
 672 }
 673
 674 } // namespace JSBSim