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 (jon@jsbsim.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   SetTurbType( ttNone );
  85   TurbGain = 0.0;
  86   TurbRate = 1.7;
  87   Rhythmicity = 0.1;
  88   spike = target_time = strength = 0.0;
  89   wind_from_clockwise = 0.0;
  90   SutherlandConstant = 198.72; // deg Rankine
  91   Beta = 2.269690E-08; // slug/(sec ft R^0.5)
  92
  93   T_dev_sl = T_dev = delta_T = 0.0;
  94   StandardTempOnly = false;
  95   first_pass = true;
  96   vGustNED.InitMatrix();
  97   vTurbulenceNED.InitMatrix();
  98
  99   bind();
 100   Debug(0);
 101 }
 102
 103 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 104
 105 FGAtmosphere::~FGAtmosphere()
 106 {
 107   Debug(1);
 108 }
 109
 110 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 111
 112 bool FGAtmosphere::InitModel(void)
 113 {
 114   if (!FGModel::InitModel()) return false;
 115
 116   UseInternal();  // this is the default
 117
 118   Calculate(h);
 119   StdSLtemperature = SLtemperature = 518.67;
 120   StdSLpressure    = SLpressure = 2116.22;
 121   StdSLdensity     = SLdensity = 0.00237767;
 122   StdSLsoundspeed  = SLsoundspeed = sqrt(SHRatio*Reng*StdSLtemperature);
 123   rSLtemperature = 1.0/StdSLtemperature;
 124   rSLpressure    = 1.0/StdSLpressure;
 125   rSLdensity     = 1.0/StdSLdensity;
 126   rSLsoundspeed  = 1.0/StdSLsoundspeed;
 127
 128   return true;
 129 }
 130
 131 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 132
 133 bool FGAtmosphere::Run(void)
 134 {
 135   if (FGModel::Run()) return true;
 136   if (FDMExec->Holding()) return false;
 137
 138   T_dev = 0.0;
 139   h = Propagate->GetAltitudeASL();
 140
 141   if (!useExternal) {
 142     Calculate(h);
 143     CalculateDerived();
 144   } else {
 145     CalculateDerived();
 146   }
 147
 148   Debug(2);
 149   return false;
 150 }
 151
 152 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 153 //
 154 // See reference 1
 155
 156 void FGAtmosphere::Calculate(double altitude)
 157 {
 158   double slope, reftemp, refpress;
 159   int i = lastIndex;
 160
 161   if (altitude < htab[lastIndex]) {
 162     if (altitude <= 0) {
 163       i = 0;
 164       altitude=0;
 165     } else {
 166        i = lastIndex-1;
 167        while (htab[i] > altitude) i--;
 168     }
 169   } else if (altitude > htab[lastIndex+1]) {
 170     if (altitude >= htab[7]) {
 171       i = 7;
 172       altitude = htab[7];
 173     } else {
 174       i = lastIndex+1;
 175       while (htab[i+1] < altitude) i++;
 176     }
 177   }
 178
 179   switch(i) {
 180   case 0: // Sea level
 181     slope     = -0.00356616; // R/ft.
 182     reftemp   = 518.67;   // in degrees Rankine, 288.15 Kelvin
 183     refpress  = 2116.22;    // psf
 184     //refdens   = 0.00237767;  // slugs/cubic ft.
 185     break;
 186   case 1:     // 36089 ft. or 11 km
 187     slope     = 0;
 188     reftemp   = 389.97; // in degrees Rankine, 216.65 Kelvin
 189     refpress  = 472.763;
 190     //refdens   = 0.000706032;
 191     break;
 192   case 2:     // 65616 ft. or 20 km
 193     slope     = 0.00054864;
 194     reftemp   = 389.97; // in degrees Rankine, 216.65 Kelvin
 195     refpress  = 114.636;
 196     //refdens   = 0.000171306;
 197     break;
 198   case 3:     // 104986 ft. or 32 km
 199     slope     = 0.001536192;
 200     reftemp   = 411.57; // in degrees Rankine, 228.65 Kelvin
 201     refpress  = 18.128;
 202     //refdens   = 1.18422e-05;
 203     break;
 204   case 4:     // 154199 ft. 47 km
 205     slope     = 0;
 206     reftemp   = 487.17; // in degrees Rankine, 270.65 Kelvin
 207     refpress  = 2.316;
 208     //refdens   = 4.00585e-7;
 209     break;
 210   case 5:     // 167322 ft. or 51 km
 211     slope     = -0.001536192;
 212     reftemp   = 487.17; // in degrees Rankine, 270.65 Kelvin
 213     refpress  = 1.398;
 214     //refdens   = 8.17102e-7;
 215     break;
 216   case 6:     // 232940 ft. or 71 km
 217     slope     = -0.00109728;
 218     reftemp   = 386.368; // in degrees Rankine, 214.649 Kelvin
 219     refpress  = 0.0826;
 220     //refdens   = 8.77702e-9;
 221     break;
 222   case 7:     // 278385 ft. or 84.8520 km
 223     slope     = 0;
 224     reftemp   = 336.5; // in degrees Rankine, 186.94 Kelvin
 225     refpress  = 0.00831;
 226     //refdens   = 2.19541e-10;
 227     break;
 228   default:     // sea level
 229     slope     = -0.00356616; // R/ft.
 230     reftemp   = 518.67;   // in degrees Rankine, 288.15 Kelvin
 231     refpress  = 2116.22;    // psf
 232     //refdens   = 0.00237767;  // slugs/cubic ft.
 233     break;
 234
 235   }
 236
 237   // If delta_T is set, then that is our temperature deviation at any altitude.
 238   // If not, then we'll estimate a deviation based on the sea level deviation (if set).
 239
 240   if(!StandardTempOnly) {
 241     T_dev = 0.0;
 242     if (delta_T != 0.0) {
 243       T_dev = delta_T;
 244     } else {
 245       if ((altitude < 36089.239) && (T_dev_sl != 0.0)) {
 246         T_dev = T_dev_sl * ( 1.0 - (altitude/36089.239));
 247       }
 248     }
 249     reftemp+=T_dev;
 250   }
 251
 252   if (slope == 0) {
 253     intTemperature = reftemp;
 254     intPressure = refpress*exp(-Inertial->SLgravity()/(reftemp*Reng)*(altitude-htab[i]));
 255     intDensity = intPressure/(Reng*intTemperature);
 256   } else {
 257     intTemperature = reftemp+slope*(altitude-htab[i]);
 258     intPressure = refpress*pow(intTemperature/reftemp,-Inertial->SLgravity()/(slope*Reng));
 259     intDensity = intPressure/(Reng*intTemperature);
 260   }
 261
 262   lastIndex=i;
 263 }
 264
 265 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 266 // Calculate parameters derived from T, P and rho
 267 // Sum gust and turbulence values in NED frame into the wind vector.
 268
 269 void FGAtmosphere::CalculateDerived(void)
 270 {
 271   T_dev = (*temperature) - GetTemperature(h);
 272   density_altitude = h + T_dev * 66.7;
 273
 274   if (turbType != ttNone) Turbulence();
 275
 276   vTotalWindNED = vWindNED + vGustNED + vTurbulenceNED;
 277
 278    // psiw (Wind heading) is the direction the wind is blowing towards
 279   if (vWindNED(eX) != 0.0) psiw = atan2( vWindNED(eY), vWindNED(eX) );
 280   if (psiw < 0) psiw += 2*M_PI;
 281
 282   soundspeed = sqrt(SHRatio*Reng*(*temperature));
 283
 284   intViscosity = Beta * pow(intTemperature, 1.5) / (SutherlandConstant + intTemperature);
 285   intKinematicViscosity = intViscosity / intDensity;
 286 }
 287
 288
 289 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 290 // Get the standard atmospheric properties at a specified altitude
 291
 292 void FGAtmosphere::GetStdAtmosphere(double altitude) {
 293   StandardTempOnly = true;
 294   Calculate(altitude);
 295   StandardTempOnly = false;
 296   atmosphere.Temperature = intTemperature;
 297   atmosphere.Pressure = intPressure;
 298   atmosphere.Density = intDensity;
 299
 300   // Reset the internal atmospheric state
 301   Calculate(h);
 302 }
 303
 304 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 305 // Get the standard pressure at a specified altitude
 306
 307 double FGAtmosphere::GetPressure(double altitude) {
 308   GetStdAtmosphere(altitude);
 309   return atmosphere.Pressure;
 310 }
 311
 312 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 313 // Get the standard temperature at a specified altitude
 314
 315 double FGAtmosphere::GetTemperature(double altitude) {
 316   GetStdAtmosphere(altitude);
 317   return atmosphere.Temperature;
 318 }
 319
 320 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 321 // Get the standard density at a specified altitude
 322
 323 double FGAtmosphere::GetDensity(double altitude) {
 324   GetStdAtmosphere(altitude);
 325   return atmosphere.Density;
 326 }
 327
 328
 329 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 330 // square a value, but preserve the original sign
 331
 332 static inline double square_signed (double value)
 333 {
 334     if (value < 0)
 335         return value * value * -1;
 336     else
 337         return value * value;
 338 }
 339
 340 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 341 //
 342 // psi is the angle that the wind is blowing *towards*
 343
 344 void FGAtmosphere::SetWindspeed(double speed)
 345 {
 346   if (vWindNED.Magnitude() == 0.0) {
 347     psiw = 0.0;
 348     vWindNED(eNorth) = speed;
 349   } else {
 350     vWindNED(eNorth) = speed * cos(psiw);
 351     vWindNED(eEast) = speed * sin(psiw);
 352     vWindNED(eDown) = 0.0;
 353   }
 354 }
 355
 356 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 357
 358 double FGAtmosphere::GetWindspeed(void) const
 359 {
 360   return vWindNED.Magnitude();
 361 }
 362
 363 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 364 //
 365 // psi is the angle that the wind is blowing *towards*
 366
 367 void FGAtmosphere::SetWindPsi(double dir)
 368 {
 369   double mag = GetWindspeed();
 370   psiw = dir;
 371   SetWindspeed(mag);
 372 }
 373
 374 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 375
 376 void FGAtmosphere::Turbulence(void)
 377 {
 378   switch (turbType) {
 379   case ttStandard: {
 380     TurbGain = TurbGain * TurbGain * 100.0;
 381
 382     vDirectiondAccelDt(eX) = 1 - 2.0*(double(rand())/double(RAND_MAX));
 383     vDirectiondAccelDt(eY) = 1 - 2.0*(double(rand())/double(RAND_MAX));
 384     vDirectiondAccelDt(eZ) = 1 - 2.0*(double(rand())/double(RAND_MAX));
 385
 386     MagnitudedAccelDt = 1 - 2.0*(double(rand())/double(RAND_MAX)) - Magnitude;
 387                                 // Scale the magnitude so that it moves
 388                                 // away from the peaks
 389     MagnitudedAccelDt = ((MagnitudedAccelDt - Magnitude) /
 390                          (1 + fabs(Magnitude)));
 391     MagnitudeAccel    += MagnitudedAccelDt*rate*TurbRate*State->Getdt();
 392     Magnitude         += MagnitudeAccel*rate*State->Getdt();
 393     Magnitude          = fabs(Magnitude);
 394
 395     vDirectiondAccelDt.Normalize();
 396
 397                                 // deemphasise non-vertical forces
 398     vDirectiondAccelDt(eX) = square_signed(vDirectiondAccelDt(eX));
 399     vDirectiondAccelDt(eY) = square_signed(vDirectiondAccelDt(eY));
 400
 401     vDirectionAccel += vDirectiondAccelDt*rate*TurbRate*State->Getdt();
 402     vDirectionAccel.Normalize();
 403     vDirection      += vDirectionAccel*rate*State->Getdt();
 404
 405     vDirection.Normalize();
 406
 407                                 // Diminish turbulence within three wingspans
 408                                 // of the ground
 409     vTurbulenceNED = TurbGain * Magnitude * vDirection;
 410     double HOverBMAC = Auxiliary->GetHOverBMAC();
 411     if (HOverBMAC < 3.0)
 412         vTurbulenceNED *= (HOverBMAC / 3.0) * (HOverBMAC / 3.0);
 413
 414     // I don't believe these next two statements calculate the proper gradient over
 415     // the aircraft body. One reason is because this has no relationship with the
 416     // orientation or velocity of the aircraft, which it must have. What is vTurbulenceGrad
 417     // supposed to represent? And the direction and magnitude of the turbulence can change,
 418     // so both accelerations need to be accounted for, no?
 419
 420     // Need to determine the turbulence change in body axes between two time points.
 421
 422     vTurbulenceGrad = TurbGain*MagnitudeAccel * vDirection;
 423     vBodyTurbGrad = Propagate->GetTl2b()*vTurbulenceGrad;
 424
 425     if (Aircraft->GetWingSpan() > 0) {
 426       vTurbPQR(eP) = vBodyTurbGrad(eY)/Aircraft->GetWingSpan();
 427     } else {
 428       vTurbPQR(eP) = vBodyTurbGrad(eY)/30.0;
 429     }
 430 //     if (Aircraft->GetHTailArm() != 0.0)
 431 //       vTurbPQR(eQ) = vBodyTurbGrad(eZ)/Aircraft->GetHTailArm();
 432 //     else
 433 //       vTurbPQR(eQ) = vBodyTurbGrad(eZ)/10.0;
 434
 435     if (Aircraft->GetVTailArm() > 0)
 436       vTurbPQR(eR) = vBodyTurbGrad(eX)/Aircraft->GetVTailArm();
 437     else
 438       vTurbPQR(eR) = vBodyTurbGrad(eX)/10.0;
 439
 440                                 // Clear the horizontal forces
 441                                 // actually felt by the plane, now
 442                                 // that we've used them to calculate
 443                                 // moments.
 444                                 // Why? (JSB)
 445 //    vTurbulenceNED(eX) = 0.0;
 446 //    vTurbulenceNED(eY) = 0.0;
 447
 448     break;
 449   }
 450   case ttBerndt: { // This is very experimental and incomplete at the moment.
 451
 452     TurbGain = TurbGain * TurbGain * 100.0;
 453
 454     vDirectiondAccelDt(eX) = 1 - 2.0*(double(rand())/double(RAND_MAX));
 455     vDirectiondAccelDt(eY) = 1 - 2.0*(double(rand())/double(RAND_MAX));
 456     vDirectiondAccelDt(eZ) = 1 - 2.0*(double(rand())/double(RAND_MAX));
 457
 458
 459     MagnitudedAccelDt = 1 - 2.0*(double(rand())/double(RAND_MAX)) - Magnitude;
 460     MagnitudeAccel    += MagnitudedAccelDt*rate*State->Getdt();
 461     Magnitude         += MagnitudeAccel*rate*State->Getdt();
 462
 463     vDirectiondAccelDt.Normalize();
 464     vDirectionAccel += vDirectiondAccelDt*rate*State->Getdt();
 465     vDirectionAccel.Normalize();
 466     vDirection      += vDirectionAccel*rate*State->Getdt();
 467
 468                                 // Diminish z-vector within two wingspans
 469                                 // of the ground
 470     double HOverBMAC = Auxiliary->GetHOverBMAC();
 471     if (HOverBMAC < 2.0)
 472         vDirection(eZ) *= HOverBMAC / 2.0;
 473
 474     vDirection.Normalize();
 475
 476     vTurbulenceNED = TurbGain*Magnitude * vDirection;
 477     vTurbulenceGrad = TurbGain*MagnitudeAccel * vDirection;
 478
 479     vBodyTurbGrad = Propagate->GetTl2b()*vTurbulenceGrad;
 480     vTurbPQR(eP) = vBodyTurbGrad(eY)/Aircraft->GetWingSpan();
 481     if (Aircraft->GetHTailArm() > 0)
 482       vTurbPQR(eQ) = vBodyTurbGrad(eZ)/Aircraft->GetHTailArm();
 483     else
 484       vTurbPQR(eQ) = vBodyTurbGrad(eZ)/10.0;
 485
 486     if (Aircraft->GetVTailArm() > 0)
 487       vTurbPQR(eR) = vBodyTurbGrad(eX)/Aircraft->GetVTailArm();
 488     else
 489       vTurbPQR(eR) = vBodyTurbGrad(eX)/10.0;
 490
 491     break;
 492   }
 493   case ttCulp: {
 494
 495     vTurbPQR(eP) = wind_from_clockwise;
 496     if (TurbGain == 0.0) return;
 497
 498     // keep the inputs within allowable limts for this model
 499     if (TurbGain < 0.0) TurbGain = 0.0;
 500     if (TurbGain > 1.0) TurbGain = 1.0;
 501     if (TurbRate < 0.0) TurbRate = 0.0;
 502     if (TurbRate > 30.0) TurbRate = 30.0;
 503     if (Rhythmicity < 0.0) Rhythmicity = 0.0;
 504     if (Rhythmicity > 1.0) Rhythmicity = 1.0;
 505
 506     // generate a sine wave corresponding to turbulence rate in hertz
 507     double time = FDMExec->GetSimTime();
 508     double sinewave = sin( time * TurbRate * 6.283185307 );
 509
 510     double random = 0.0;
 511     if (target_time == 0.0) {
 512       strength = random = 1 - 2.0*(double(rand())/double(RAND_MAX));
 513       target_time = time + 0.71 + (random * 0.5);
 514     }
 515     if (time > target_time) {
 516       spike = 1.0;
 517       target_time = 0.0;
 518     }
 519
 520     // max vertical wind speed in fps, corresponds to TurbGain = 1.0
 521     double max_vs = 40;
 522
 523     vTurbulenceNED(1) = vTurbulenceNED(2) = vTurbulenceNED(3) = 0.0;
 524     double delta = strength * max_vs * TurbGain * (1-Rhythmicity) * spike;
 525
 526     // Vertical component of turbulence.
 527     vTurbulenceNED(3) = sinewave * max_vs * TurbGain * Rhythmicity;
 528     vTurbulenceNED(3)+= delta;
 529     double HOverBMAC = Auxiliary->GetHOverBMAC();
 530     if (HOverBMAC < 3.0)
 531         vTurbulenceNED(3) *= HOverBMAC * 0.3333;
 532
 533     // Yaw component of turbulence.
 534     vTurbulenceNED(1) = sin( delta * 3.0 );
 535     vTurbulenceNED(2) = cos( delta * 3.0 );
 536
 537     // Roll component of turbulence. Clockwise vortex causes left roll.
 538     vTurbPQR(eP) += delta * 0.04;
 539
 540     spike = spike * 0.9;
 541     break;
 542   }
 543   default:
 544     break;
 545   }
 546 }
 547
 548 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 549
 550 void FGAtmosphere::UseExternal(void)
 551 {
 552   temperature=&exTemperature;
 553   pressure=&exPressure;
 554   density=&exDensity;
 555   useExternal=true;
 556 }
 557
 558 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 559
 560 void FGAtmosphere::UseInternal(void)
 561 {
 562   temperature=&intTemperature;
 563   pressure=&intPressure;
 564   density=&intDensity;
 565   useExternal=false;
 566 }
 567
 568 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 569
 570 void FGAtmosphere::bind(void)
 571 {
 572   typedef double (FGAtmosphere::*PMF)(int) const;
 573   typedef double (FGAtmosphere::*PMFv)(void) const;
 574   typedef void   (FGAtmosphere::*PMFd)(int,double);
 575   PropertyManager->Tie("atmosphere/T-R", this, (PMFv)&FGAtmosphere::GetTemperature);
 576   PropertyManager->Tie("atmosphere/rho-slugs_ft3", this, (PMFv)&FGAtmosphere::GetDensity);
 577   PropertyManager->Tie("atmosphere/P-psf", this, (PMFv)&FGAtmosphere::GetPressure);
 578   PropertyManager->Tie("atmosphere/a-fps", this, &FGAtmosphere::GetSoundSpeed);
 579   PropertyManager->Tie("atmosphere/T-sl-R", this, &FGAtmosphere::GetTemperatureSL);
 580   PropertyManager->Tie("atmosphere/rho-sl-slugs_ft3", this, &FGAtmosphere::GetDensitySL);
 581   PropertyManager->Tie("atmosphere/P-sl-psf", this, &FGAtmosphere::GetPressureSL);
 582   PropertyManager->Tie("atmosphere/a-sl-fps", this, &FGAtmosphere::GetSoundSpeedSL);
 583   PropertyManager->Tie("atmosphere/theta", this, &FGAtmosphere::GetTemperatureRatio);
 584   PropertyManager->Tie("atmosphere/sigma", this, &FGAtmosphere::GetDensityRatio);
 585   PropertyManager->Tie("atmosphere/delta", this, &FGAtmosphere::GetPressureRatio);
 586   PropertyManager->Tie("atmosphere/a-ratio", this, &FGAtmosphere::GetSoundSpeedRatio);
 587   PropertyManager->Tie("atmosphere/psiw-rad", this, &FGAtmosphere::GetWindPsi, &FGAtmosphere::SetWindPsi);
 588   PropertyManager->Tie("atmosphere/delta-T", this, &FGAtmosphere::GetDeltaT, &FGAtmosphere::SetDeltaT);
 589   PropertyManager->Tie("atmosphere/T-sl-dev-F", this, &FGAtmosphere::GetSLTempDev, &FGAtmosphere::SetSLTempDev);
 590   PropertyManager->Tie("atmosphere/density-altitude", this, &FGAtmosphere::GetDensityAltitude);
 591
 592   PropertyManager->Tie("atmosphere/wind-north-fps", this, eNorth, (PMF)&FGAtmosphere::GetWindNED,
 593                                                           (PMFd)&FGAtmosphere::SetWindNED);
 594   PropertyManager->Tie("atmosphere/wind-east-fps",  this, eEast, (PMF)&FGAtmosphere::GetWindNED,
 595                                                           (PMFd)&FGAtmosphere::SetWindNED);
 596   PropertyManager->Tie("atmosphere/wind-down-fps",  this, eDown, (PMF)&FGAtmosphere::GetWindNED,
 597                                                           (PMFd)&FGAtmosphere::SetWindNED);
 598   PropertyManager->Tie("atmosphere/wind-mag-fps", this, &FGAtmosphere::GetWindspeed,
 599                                                         &FGAtmosphere::SetWindspeed);
 600   PropertyManager->Tie("atmosphere/total-wind-north-fps", this, eNorth, (PMF)&FGAtmosphere::GetTotalWindNED);
 601   PropertyManager->Tie("atmosphere/total-wind-east-fps",  this, eEast,  (PMF)&FGAtmosphere::GetTotalWindNED);
 602   PropertyManager->Tie("atmosphere/total-wind-down-fps",  this, eDown,  (PMF)&FGAtmosphere::GetTotalWindNED);
 603
 604   PropertyManager->Tie("atmosphere/gust-north-fps", this, eNorth, (PMF)&FGAtmosphere::GetGustNED,
 605                                                           (PMFd)&FGAtmosphere::SetGustNED);
 606   PropertyManager->Tie("atmosphere/gust-east-fps",  this, eEast, (PMF)&FGAtmosphere::GetGustNED,
 607                                                           (PMFd)&FGAtmosphere::SetGustNED);
 608   PropertyManager->Tie("atmosphere/gust-down-fps",  this, eDown, (PMF)&FGAtmosphere::GetGustNED,
 609                                                           (PMFd)&FGAtmosphere::SetGustNED);
 610
 611   PropertyManager->Tie("atmosphere/p-turb-rad_sec", this,1, (PMF)&FGAtmosphere::GetTurbPQR);
 612   PropertyManager->Tie("atmosphere/q-turb-rad_sec", this,2, (PMF)&FGAtmosphere::GetTurbPQR);
 613   PropertyManager->Tie("atmosphere/r-turb-rad_sec", this,3, (PMF)&FGAtmosphere::GetTurbPQR);
 614   PropertyManager->Tie("atmosphere/turb-rate", this, &FGAtmosphere::GetTurbRate, &FGAtmosphere::SetTurbRate);
 615   PropertyManager->Tie("atmosphere/turb-gain", this, &FGAtmosphere::GetTurbGain, &FGAtmosphere::SetTurbGain);
 616   PropertyManager->Tie("atmosphere/turb-rhythmicity", this, &FGAtmosphere::GetRhythmicity,
 617                                                             &FGAtmosphere::SetRhythmicity);
 618 }
 619
 620 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 621 //    The bitmasked value choices are as follows:
 622 //    unset: In this case (the default) JSBSim would only print
 623 //       out the normally expected messages, essentially echoing
 624 //       the config files as they are read. If the environment
 625 //       variable is not set, debug_lvl is set to 1 internally
 626 //    0: This requests JSBSim not to output any messages
 627 //       whatsoever.
 628 //    1: This value explicity requests the normal JSBSim
 629 //       startup messages
 630 //    2: This value asks for a message to be printed out when
 631 //       a class is instantiated
 632 //    4: When this value is set, a message is displayed when a
 633 //       FGModel object executes its Run() method
 634 //    8: When this value is set, various runtime state variables
 635 //       are printed out periodically
 636 //    16: When set various parameters are sanity checked and
 637 //       a message is printed out when they go out of bounds
 638
 639 void FGAtmosphere::Debug(int from)
 640 {
 641   if (debug_lvl <= 0) return;
 642
 643   if (debug_lvl & 1) { // Standard console startup message output
 644     if (from == 0) { // Constructor
 645     }
 646   }
 647   if (debug_lvl & 2 ) { // Instantiation/Destruction notification
 648     if (from == 0) cout << "Instantiated: FGAtmosphere" << endl;
 649     if (from == 1) cout << "Destroyed:    FGAtmosphere" << endl;
 650   }
 651   if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
 652   }
 653   if (debug_lvl & 8 ) { // Runtime state variables
 654   }
 655   if (debug_lvl & 16) { // Sanity checking
 656   }
 657   if (debug_lvl & 128) { // Turbulence
 658     if (first_pass && from == 2) {
 659       first_pass = false;
 660       cout << "vTurbulenceNED(X), vTurbulenceNED(Y), vTurbulenceNED(Z), "
 661            << "vTurbulenceGrad(X), vTurbulenceGrad(Y), vTurbulenceGrad(Z), "
 662            << "vDirection(X), vDirection(Y), vDirection(Z), "
 663            << "Magnitude, "
 664            << "vTurbPQR(P), vTurbPQR(Q), vTurbPQR(R), " << endl;
 665     }
 666     if (from == 2) {
 667       cout << vTurbulenceNED << ", " << vTurbulenceGrad << ", " << vDirection << ", " << Magnitude << ", " << vTurbPQR << endl;
 668     }
 669   }
 670   if (debug_lvl & 64) {
 671     if (from == 0) { // Constructor
 672       cout << IdSrc << endl;
 673       cout << IdHdr << endl;
 674     }
 675   }
 676 }
 677
 678 } // namespace JSBSim