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 #include <iostream>
  58 #include <cstdlib>
  59
  60 using namespace std;
  61
  62 namespace JSBSim {
  63
  64 static const char *IdSrc = "$Id$";
  65 static const char *IdHdr = ID_ATMOSPHERE;
  66
  67 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  68 CLASS IMPLEMENTATION
  69 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  70
  71 FGAtmosphere::FGAtmosphere(FGFDMExec* fdmex) : FGModel(fdmex)
  72 {
  73   Name = "FGAtmosphere";
  74   lastIndex = 0;
  75   h = 0.0;
  76   psiw = 0.0;
  77   htab[0]=0;
  78   htab[1]= 36089.0;
  79   htab[2]= 65617.0;
  80   htab[3]=104987.0;
  81   htab[4]=154199.0;
  82   htab[5]=167322.0;
  83   htab[6]=232940.0;
  84   htab[7]=278385.0; //ft.
  85
  86   MagnitudedAccelDt = MagnitudeAccel = Magnitude = 0.0;
  87 //  SetTurbType( ttCulp );
  88   SetTurbType( ttNone );
  89   TurbGain = 1.0;
  90   TurbRate = 10.0;
  91   Rhythmicity = 0.1;
  92   spike = target_time = strength = 0.0;
  93   wind_from_clockwise = 0.0;
  94   SutherlandConstant = 198.72; // deg Rankine
  95   Beta = 2.269690E-08; // slug/(sec ft R^0.5)
  96
  97   T_dev_sl = T_dev = delta_T = 0.0;
  98   StandardTempOnly = false;
  99   first_pass = true;
 100   vGustNED.InitMatrix();
 101   vTurbulenceNED.InitMatrix();
 102
 103   bind();
 104   Debug(0);
 105 }
 106
 107 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 108
 109 FGAtmosphere::~FGAtmosphere()
 110 {
 111   Debug(1);
 112 }
 113
 114 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 115
 116 bool FGAtmosphere::InitModel(void)
 117 {
 118   if (!FGModel::InitModel()) return false;
 119
 120   UseInternal();  // this is the default
 121
 122   Calculate(h);
 123   StdSLtemperature = SLtemperature = 518.67;
 124   StdSLpressure    = SLpressure = 2116.22;
 125   StdSLdensity     = SLdensity = 0.00237767;
 126   StdSLsoundspeed  = SLsoundspeed = sqrt(SHRatio*Reng*StdSLtemperature);
 127   rSLtemperature = 1.0/StdSLtemperature;
 128   rSLpressure    = 1.0/StdSLpressure;
 129   rSLdensity     = 1.0/StdSLdensity;
 130   rSLsoundspeed  = 1.0/StdSLsoundspeed;
 131
 132   return true;
 133 }
 134
 135 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 136
 137 bool FGAtmosphere::Run(void)
 138 {
 139   if (FGModel::Run()) return true;
 140   if (FDMExec->Holding()) return false;
 141
 142   RunPreFunctions();
 143
 144   T_dev = 0.0;
 145   h = Propagate->GetAltitudeASL();
 146
 147   if (!useExternal) {
 148     Calculate(h);
 149     CalculateDerived();
 150   } else {
 151     CalculateDerived();
 152   }
 153
 154   RunPostFunctions();
 155
 156   Debug(2);
 157   return false;
 158 }
 159
 160 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 161 //
 162 // See reference 1
 163
 164 void FGAtmosphere::Calculate(double altitude)
 165 {
 166   double slope, reftemp, refpress;
 167   int i = lastIndex;
 168
 169   if (altitude < htab[lastIndex]) {
 170     if (altitude <= 0) {
 171       i = 0;
 172       altitude=0;
 173     } else {
 174        i = lastIndex-1;
 175        while (htab[i] > altitude) i--;
 176     }
 177   } else if (altitude > htab[lastIndex+1]) {
 178     if (altitude >= htab[7]) {
 179       i = 7;
 180       altitude = htab[7];
 181     } else {
 182       i = lastIndex+1;
 183       while (htab[i+1] < altitude) i++;
 184     }
 185   }
 186
 187   switch(i) {
 188   case 0: // Sea level
 189     slope     = -0.00356616; // R/ft.
 190     reftemp   = 518.67;   // in degrees Rankine, 288.15 Kelvin
 191     refpress  = 2116.22;    // psf
 192     //refdens   = 0.00237767;  // slugs/cubic ft.
 193     break;
 194   case 1:     // 36089 ft. or 11 km
 195     slope     = 0;
 196     reftemp   = 389.97; // in degrees Rankine, 216.65 Kelvin
 197     refpress  = 472.763;
 198     //refdens   = 0.000706032;
 199     break;
 200   case 2:     // 65616 ft. or 20 km
 201     slope     = 0.00054864;
 202     reftemp   = 389.97; // in degrees Rankine, 216.65 Kelvin
 203     refpress  = 114.636;
 204     //refdens   = 0.000171306;
 205     break;
 206   case 3:     // 104986 ft. or 32 km
 207     slope     = 0.001536192;
 208     reftemp   = 411.57; // in degrees Rankine, 228.65 Kelvin
 209     refpress  = 18.128;
 210     //refdens   = 1.18422e-05;
 211     break;
 212   case 4:     // 154199 ft. 47 km
 213     slope     = 0;
 214     reftemp   = 487.17; // in degrees Rankine, 270.65 Kelvin
 215     refpress  = 2.316;
 216     //refdens   = 4.00585e-7;
 217     break;
 218   case 5:     // 167322 ft. or 51 km
 219     slope     = -0.001536192;
 220     reftemp   = 487.17; // in degrees Rankine, 270.65 Kelvin
 221     refpress  = 1.398;
 222     //refdens   = 8.17102e-7;
 223     break;
 224   case 6:     // 232940 ft. or 71 km
 225     slope     = -0.00109728;
 226     reftemp   = 386.368; // in degrees Rankine, 214.649 Kelvin
 227     refpress  = 0.0826;
 228     //refdens   = 8.77702e-9;
 229     break;
 230   case 7:     // 278385 ft. or 84.8520 km
 231     slope     = 0;
 232     reftemp   = 336.5; // in degrees Rankine, 186.94 Kelvin
 233     refpress  = 0.00831;
 234     //refdens   = 2.19541e-10;
 235     break;
 236   default:     // sea level
 237     slope     = -0.00356616; // R/ft.
 238     reftemp   = 518.67;   // in degrees Rankine, 288.15 Kelvin
 239     refpress  = 2116.22;    // psf
 240     //refdens   = 0.00237767;  // slugs/cubic ft.
 241     break;
 242
 243   }
 244
 245   // If delta_T is set, then that is our temperature deviation at any altitude.
 246   // If not, then we'll estimate a deviation based on the sea level deviation (if set).
 247
 248   if(!StandardTempOnly) {
 249     T_dev = 0.0;
 250     if (delta_T != 0.0) {
 251       T_dev = delta_T;
 252     } else {
 253       if ((altitude < 36089.239) && (T_dev_sl != 0.0)) {
 254         T_dev = T_dev_sl * ( 1.0 - (altitude/36089.239));
 255       }
 256     }
 257     reftemp+=T_dev;
 258   }
 259
 260   if (slope == 0) {
 261     intTemperature = reftemp;
 262     intPressure = refpress*exp(-Inertial->SLgravity()/(reftemp*Reng)*(altitude-htab[i]));
 263     intDensity = intPressure/(Reng*intTemperature);
 264   } else {
 265     intTemperature = reftemp+slope*(altitude-htab[i]);
 266     intPressure = refpress*pow(intTemperature/reftemp,-Inertial->SLgravity()/(slope*Reng));
 267     intDensity = intPressure/(Reng*intTemperature);
 268   }
 269
 270   lastIndex=i;
 271 }
 272
 273 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 274 // Calculate parameters derived from T, P and rho
 275 // Sum gust and turbulence values in NED frame into the wind vector.
 276
 277 void FGAtmosphere::CalculateDerived(void)
 278 {
 279   T_dev = (*temperature) - GetTemperature(h);
 280   density_altitude = h + T_dev * 66.7;
 281
 282   if (turbType != ttNone) Turbulence();
 283
 284   vTotalWindNED = vWindNED + vGustNED + vTurbulenceNED;
 285
 286    // psiw (Wind heading) is the direction the wind is blowing towards
 287   if (vWindNED(eX) != 0.0) psiw = atan2( vWindNED(eY), vWindNED(eX) );
 288   if (psiw < 0) psiw += 2*M_PI;
 289
 290   soundspeed = sqrt(SHRatio*Reng*(*temperature));
 291
 292   intViscosity = Beta * pow(intTemperature, 1.5) / (SutherlandConstant + intTemperature);
 293   intKinematicViscosity = intViscosity / intDensity;
 294 }
 295
 296
 297 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 298 // Get the standard atmospheric properties at a specified altitude
 299
 300 void FGAtmosphere::GetStdAtmosphere(double altitude) {
 301   StandardTempOnly = true;
 302   Calculate(altitude);
 303   StandardTempOnly = false;
 304   atmosphere.Temperature = intTemperature;
 305   atmosphere.Pressure = intPressure;
 306   atmosphere.Density = intDensity;
 307
 308   // Reset the internal atmospheric state
 309   Calculate(h);
 310 }
 311
 312 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 313 // Get the standard pressure at a specified altitude
 314
 315 double FGAtmosphere::GetPressure(double altitude) {
 316   GetStdAtmosphere(altitude);
 317   return atmosphere.Pressure;
 318 }
 319
 320 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 321 // Get the standard temperature at a specified altitude
 322
 323 double FGAtmosphere::GetTemperature(double altitude) {
 324   GetStdAtmosphere(altitude);
 325   return atmosphere.Temperature;
 326 }
 327
 328 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 329 // Get the standard density at a specified altitude
 330
 331 double FGAtmosphere::GetDensity(double altitude) {
 332   GetStdAtmosphere(altitude);
 333   return atmosphere.Density;
 334 }
 335
 336
 337 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 338 // square a value, but preserve the original sign
 339
 340 static inline double square_signed (double value)
 341 {
 342     if (value < 0)
 343         return value * value * -1;
 344     else
 345         return value * value;
 346 }
 347
 348 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 349 //
 350 // psi is the angle that the wind is blowing *towards*
 351
 352 void FGAtmosphere::SetWindspeed(double speed)
 353 {
 354   if (vWindNED.Magnitude() == 0.0) {
 355     psiw = 0.0;
 356     vWindNED(eNorth) = speed;
 357   } else {
 358     vWindNED(eNorth) = speed * cos(psiw);
 359     vWindNED(eEast) = speed * sin(psiw);
 360     vWindNED(eDown) = 0.0;
 361   }
 362 }
 363
 364 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 365
 366 double FGAtmosphere::GetWindspeed(void) const
 367 {
 368   return vWindNED.Magnitude();
 369 }
 370
 371 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 372 //
 373 // psi is the angle that the wind is blowing *towards*
 374
 375 void FGAtmosphere::SetWindPsi(double dir)
 376 {
 377   double mag = GetWindspeed();
 378   psiw = dir;
 379   SetWindspeed(mag);
 380 }
 381
 382 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 383
 384 void FGAtmosphere::Turbulence(void)
 385 {
 386   double DeltaT = rate*State->Getdt();
 387
 388   switch (turbType) {
 389   case ttStandard: {
 390     // TurbGain = TurbGain * TurbGain * 100.0; // what is this!?
 391
 392     vDirectiondAccelDt(eX) = 1 - 2.0*(double(rand())/double(RAND_MAX));
 393     vDirectiondAccelDt(eY) = 1 - 2.0*(double(rand())/double(RAND_MAX));
 394     vDirectiondAccelDt(eZ) = 1 - 2.0*(double(rand())/double(RAND_MAX));
 395
 396     MagnitudedAccelDt = 1 - 2.0*(double(rand())/double(RAND_MAX)) - Magnitude;
 397                                 // Scale the magnitude so that it moves
 398                                 // away from the peaks
 399     MagnitudedAccelDt = ((MagnitudedAccelDt - Magnitude) /
 400                          (1 + fabs(Magnitude)));
 401     MagnitudeAccel    += MagnitudedAccelDt*TurbRate*DeltaT;
 402     Magnitude         += MagnitudeAccel*DeltaT;
 403     Magnitude          = fabs(Magnitude);
 404
 405     vDirectiondAccelDt.Normalize();
 406
 407                                 // deemphasise non-vertical forces
 408     vDirectiondAccelDt(eX) = square_signed(vDirectiondAccelDt(eX));
 409     vDirectiondAccelDt(eY) = square_signed(vDirectiondAccelDt(eY));
 410
 411     vDirectionAccel += vDirectiondAccelDt*TurbRate*DeltaT;
 412     vDirectionAccel.Normalize();
 413     vDirection      += vDirectionAccel*DeltaT;
 414
 415     vDirection.Normalize();
 416
 417                                 // Diminish turbulence within three wingspans
 418                                 // of the ground
 419     vTurbulenceNED = TurbGain * Magnitude * vDirection;
 420     double HOverBMAC = Auxiliary->GetHOverBMAC();
 421     if (HOverBMAC < 3.0)
 422         vTurbulenceNED *= (HOverBMAC / 3.0) * (HOverBMAC / 3.0);
 423
 424     // I don't believe these next two statements calculate the proper gradient over
 425     // the aircraft body. One reason is because this has no relationship with the
 426     // orientation or velocity of the aircraft, which it must have. What is vTurbulenceGrad
 427     // supposed to represent? And the direction and magnitude of the turbulence can change,
 428     // so both accelerations need to be accounted for, no?
 429
 430     // Need to determine the turbulence change in body axes between two time points.
 431
 432     vTurbulenceGrad = TurbGain*MagnitudeAccel * vDirection;
 433     vBodyTurbGrad = Propagate->GetTl2b()*vTurbulenceGrad;
 434
 435     if (Aircraft->GetWingSpan() > 0) {
 436       vTurbPQR(eP) = vBodyTurbGrad(eY)/Aircraft->GetWingSpan();
 437     } else {
 438       vTurbPQR(eP) = vBodyTurbGrad(eY)/30.0;
 439     }
 440 //     if (Aircraft->GetHTailArm() != 0.0)
 441 //       vTurbPQR(eQ) = vBodyTurbGrad(eZ)/Aircraft->GetHTailArm();
 442 //     else
 443 //       vTurbPQR(eQ) = vBodyTurbGrad(eZ)/10.0;
 444
 445     if (Aircraft->GetVTailArm() > 0)
 446       vTurbPQR(eR) = vBodyTurbGrad(eX)/Aircraft->GetVTailArm();
 447     else
 448       vTurbPQR(eR) = vBodyTurbGrad(eX)/10.0;
 449
 450                                 // Clear the horizontal forces
 451                                 // actually felt by the plane, now
 452                                 // that we've used them to calculate
 453                                 // moments.
 454                                 // Why? (JSB)
 455 //    vTurbulenceNED(eX) = 0.0;
 456 //    vTurbulenceNED(eY) = 0.0;
 457
 458     break;
 459   }
 460   case ttBerndt: { // This is very experimental and incomplete at the moment.
 461
 462     vDirectiondAccelDt(eX) = GaussianRandomNumber();
 463     vDirectiondAccelDt(eY) = GaussianRandomNumber();
 464     vDirectiondAccelDt(eZ) = GaussianRandomNumber();
 465 /*
 466     MagnitudedAccelDt = GaussianRandomNumber();
 467     MagnitudeAccel    += MagnitudedAccelDt * DeltaT;
 468     Magnitude         += MagnitudeAccel * DeltaT;
 469 */
 470     Magnitude         += GaussianRandomNumber() * DeltaT;
 471
 472     vDirectiondAccelDt.Normalize();
 473     vDirectionAccel += TurbRate * vDirectiondAccelDt * DeltaT;
 474     vDirectionAccel.Normalize();
 475     vDirection      += vDirectionAccel*DeltaT;
 476
 477     // Diminish z-vector within two wingspans of the ground
 478     double HOverBMAC = Auxiliary->GetHOverBMAC();
 479     if (HOverBMAC < 2.0) vDirection(eZ) *= HOverBMAC / 2.0;
 480
 481     vDirection.Normalize();
 482
 483     vTurbulenceNED = TurbGain*Magnitude * vDirection;
 484     vTurbulenceGrad = TurbGain*MagnitudeAccel * vDirection;
 485
 486     vBodyTurbGrad = Propagate->GetTl2b() * vTurbulenceGrad;
 487     vTurbPQR(eP) = vBodyTurbGrad(eY) / Aircraft->GetWingSpan();
 488     if (Aircraft->GetHTailArm() > 0)
 489       vTurbPQR(eQ) = vBodyTurbGrad(eZ) / Aircraft->GetHTailArm();
 490     else
 491       vTurbPQR(eQ) = vBodyTurbGrad(eZ) / 10.0;
 492
 493     if (Aircraft->GetVTailArm() > 0)
 494       vTurbPQR(eR) = vBodyTurbGrad(eX) / Aircraft->GetVTailArm();
 495     else
 496       vTurbPQR(eR) = vBodyTurbGrad(eX)/10.0;
 497
 498     break;
 499   }
 500   case ttCulp: {
 501
 502     vTurbPQR(eP) = wind_from_clockwise;
 503     if (TurbGain == 0.0) return;
 504
 505     // keep the inputs within allowable limts for this model
 506     if (TurbGain < 0.0) TurbGain = 0.0;
 507     if (TurbGain > 1.0) TurbGain = 1.0;
 508     if (TurbRate < 0.0) TurbRate = 0.0;
 509     if (TurbRate > 30.0) TurbRate = 30.0;
 510     if (Rhythmicity < 0.0) Rhythmicity = 0.0;
 511     if (Rhythmicity > 1.0) Rhythmicity = 1.0;
 512
 513     // generate a sine wave corresponding to turbulence rate in hertz
 514     double time = FDMExec->GetSimTime();
 515     double sinewave = sin( time * TurbRate * 6.283185307 );
 516
 517     double random = 0.0;
 518     if (target_time == 0.0) {
 519       strength = random = 1 - 2.0*(double(rand())/double(RAND_MAX));
 520       target_time = time + 0.71 + (random * 0.5);
 521     }
 522     if (time > target_time) {
 523       spike = 1.0;
 524       target_time = 0.0;
 525     }
 526
 527     // max vertical wind speed in fps, corresponds to TurbGain = 1.0
 528     double max_vs = 40;
 529
 530     vTurbulenceNED(1) = vTurbulenceNED(2) = vTurbulenceNED(3) = 0.0;
 531     double delta = strength * max_vs * TurbGain * (1-Rhythmicity) * spike;
 532
 533     // Vertical component of turbulence.
 534     vTurbulenceNED(3) = sinewave * max_vs * TurbGain * Rhythmicity;
 535     vTurbulenceNED(3)+= delta;
 536     double HOverBMAC = Auxiliary->GetHOverBMAC();
 537     if (HOverBMAC < 3.0)
 538         vTurbulenceNED(3) *= HOverBMAC * 0.3333;
 539
 540     // Yaw component of turbulence.
 541     vTurbulenceNED(1) = sin( delta * 3.0 );
 542     vTurbulenceNED(2) = cos( delta * 3.0 );
 543
 544     // Roll component of turbulence. Clockwise vortex causes left roll.
 545     vTurbPQR(eP) += delta * 0.04;
 546
 547     spike = spike * 0.9;
 548     break;
 549   }
 550   default:
 551     break;
 552   }
 553 }
 554
 555 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 556
 557 void FGAtmosphere::UseExternal(void)
 558 {
 559   temperature=&exTemperature;
 560   pressure=&exPressure;
 561   density=&exDensity;
 562   useExternal=true;
 563 }
 564
 565 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 566
 567 void FGAtmosphere::UseInternal(void)
 568 {
 569   temperature=&intTemperature;
 570   pressure=&intPressure;
 571   density=&intDensity;
 572   useExternal=false;
 573 }
 574
 575 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 576
 577 void FGAtmosphere::bind(void)
 578 {
 579   typedef double (FGAtmosphere::*PMF)(int) const;
 580   typedef double (FGAtmosphere::*PMFv)(void) const;
 581   typedef int (FGAtmosphere::*PMFt)(void) const;
 582   typedef void   (FGAtmosphere::*PMFd)(int,double);
 583   typedef void   (FGAtmosphere::*PMFi)(int);
 584   PropertyManager->Tie("atmosphere/T-R", this, (PMFv)&FGAtmosphere::GetTemperature);
 585   PropertyManager->Tie("atmosphere/rho-slugs_ft3", this, (PMFv)&FGAtmosphere::GetDensity);
 586   PropertyManager->Tie("atmosphere/P-psf", this, (PMFv)&FGAtmosphere::GetPressure);
 587   PropertyManager->Tie("atmosphere/a-fps", this, &FGAtmosphere::GetSoundSpeed);
 588   PropertyManager->Tie("atmosphere/T-sl-R", this, &FGAtmosphere::GetTemperatureSL);
 589   PropertyManager->Tie("atmosphere/rho-sl-slugs_ft3", this, &FGAtmosphere::GetDensitySL);
 590   PropertyManager->Tie("atmosphere/P-sl-psf", this, &FGAtmosphere::GetPressureSL);
 591   PropertyManager->Tie("atmosphere/a-sl-fps", this, &FGAtmosphere::GetSoundSpeedSL);
 592   PropertyManager->Tie("atmosphere/theta", this, &FGAtmosphere::GetTemperatureRatio);
 593   PropertyManager->Tie("atmosphere/sigma", this, &FGAtmosphere::GetDensityRatio);
 594   PropertyManager->Tie("atmosphere/delta", this, &FGAtmosphere::GetPressureRatio);
 595   PropertyManager->Tie("atmosphere/a-ratio", this, &FGAtmosphere::GetSoundSpeedRatio);
 596   PropertyManager->Tie("atmosphere/psiw-rad", this, &FGAtmosphere::GetWindPsi, &FGAtmosphere::SetWindPsi);
 597   PropertyManager->Tie("atmosphere/delta-T", this, &FGAtmosphere::GetDeltaT, &FGAtmosphere::SetDeltaT);
 598   PropertyManager->Tie("atmosphere/T-sl-dev-F", this, &FGAtmosphere::GetSLTempDev, &FGAtmosphere::SetSLTempDev);
 599   PropertyManager->Tie("atmosphere/density-altitude", this, &FGAtmosphere::GetDensityAltitude);
 600
 601   PropertyManager->Tie("atmosphere/wind-north-fps", this, eNorth, (PMF)&FGAtmosphere::GetWindNED,
 602                                                           (PMFd)&FGAtmosphere::SetWindNED);
 603   PropertyManager->Tie("atmosphere/wind-east-fps",  this, eEast, (PMF)&FGAtmosphere::GetWindNED,
 604                                                           (PMFd)&FGAtmosphere::SetWindNED);
 605   PropertyManager->Tie("atmosphere/wind-down-fps",  this, eDown, (PMF)&FGAtmosphere::GetWindNED,
 606                                                           (PMFd)&FGAtmosphere::SetWindNED);
 607   PropertyManager->Tie("atmosphere/wind-mag-fps", this, &FGAtmosphere::GetWindspeed,
 608                                                         &FGAtmosphere::SetWindspeed);
 609   PropertyManager->Tie("atmosphere/total-wind-north-fps", this, eNorth, (PMF)&FGAtmosphere::GetTotalWindNED);
 610   PropertyManager->Tie("atmosphere/total-wind-east-fps",  this, eEast,  (PMF)&FGAtmosphere::GetTotalWindNED);
 611   PropertyManager->Tie("atmosphere/total-wind-down-fps",  this, eDown,  (PMF)&FGAtmosphere::GetTotalWindNED);
 612
 613   PropertyManager->Tie("atmosphere/gust-north-fps", this, eNorth, (PMF)&FGAtmosphere::GetGustNED,
 614                                                           (PMFd)&FGAtmosphere::SetGustNED);
 615   PropertyManager->Tie("atmosphere/gust-east-fps",  this, eEast, (PMF)&FGAtmosphere::GetGustNED,
 616                                                           (PMFd)&FGAtmosphere::SetGustNED);
 617   PropertyManager->Tie("atmosphere/gust-down-fps",  this, eDown, (PMF)&FGAtmosphere::GetGustNED,
 618                                                           (PMFd)&FGAtmosphere::SetGustNED);
 619
 620   PropertyManager->Tie("atmosphere/turb-north-fps", this, eNorth, (PMF)&FGAtmosphere::GetTurbNED,
 621                                                           (PMFd)&FGAtmosphere::SetTurbNED);
 622   PropertyManager->Tie("atmosphere/turb-east-fps",  this, eEast, (PMF)&FGAtmosphere::GetTurbNED,
 623                                                           (PMFd)&FGAtmosphere::SetTurbNED);
 624   PropertyManager->Tie("atmosphere/turb-down-fps",  this, eDown, (PMF)&FGAtmosphere::GetTurbNED,
 625                                                           (PMFd)&FGAtmosphere::SetTurbNED);
 626
 627   PropertyManager->Tie("atmosphere/p-turb-rad_sec", this,1, (PMF)&FGAtmosphere::GetTurbPQR);
 628   PropertyManager->Tie("atmosphere/q-turb-rad_sec", this,2, (PMF)&FGAtmosphere::GetTurbPQR);
 629   PropertyManager->Tie("atmosphere/r-turb-rad_sec", this,3, (PMF)&FGAtmosphere::GetTurbPQR);
 630   PropertyManager->Tie("atmosphere/turb-type", this, (PMFt)&FGAtmosphere::GetTurbType, (PMFi)&FGAtmosphere::SetTurbType);
 631   PropertyManager->Tie("atmosphere/turb-rate", this, &FGAtmosphere::GetTurbRate, &FGAtmosphere::SetTurbRate);
 632   PropertyManager->Tie("atmosphere/turb-gain", this, &FGAtmosphere::GetTurbGain, &FGAtmosphere::SetTurbGain);
 633   PropertyManager->Tie("atmosphere/turb-rhythmicity", this, &FGAtmosphere::GetRhythmicity,
 634                                                             &FGAtmosphere::SetRhythmicity);
 635 }
 636
 637 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 638 //    The bitmasked value choices are as follows:
 639 //    unset: In this case (the default) JSBSim would only print
 640 //       out the normally expected messages, essentially echoing
 641 //       the config files as they are read. If the environment
 642 //       variable is not set, debug_lvl is set to 1 internally
 643 //    0: This requests JSBSim not to output any messages
 644 //       whatsoever.
 645 //    1: This value explicity requests the normal JSBSim
 646 //       startup messages
 647 //    2: This value asks for a message to be printed out when
 648 //       a class is instantiated
 649 //    4: When this value is set, a message is displayed when a
 650 //       FGModel object executes its Run() method
 651 //    8: When this value is set, various runtime state variables
 652 //       are printed out periodically
 653 //    16: When set various parameters are sanity checked and
 654 //       a message is printed out when they go out of bounds
 655
 656 void FGAtmosphere::Debug(int from)
 657 {
 658   if (debug_lvl <= 0) return;
 659
 660   if (debug_lvl & 1) { // Standard console startup message output
 661     if (from == 0) { // Constructor
 662     }
 663   }
 664   if (debug_lvl & 2 ) { // Instantiation/Destruction notification
 665     if (from == 0) cout << "Instantiated: FGAtmosphere" << endl;
 666     if (from == 1) cout << "Destroyed:    FGAtmosphere" << endl;
 667   }
 668   if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
 669   }
 670   if (debug_lvl & 8 ) { // Runtime state variables
 671   }
 672   if (debug_lvl & 16) { // Sanity checking
 673   }
 674   if (debug_lvl & 128) { // Turbulence
 675     if (first_pass && from == 2) {
 676       first_pass = false;
 677       cout << "vTurbulenceNED(X), vTurbulenceNED(Y), vTurbulenceNED(Z), "
 678            << "vTurbulenceGrad(X), vTurbulenceGrad(Y), vTurbulenceGrad(Z), "
 679            << "vDirection(X), vDirection(Y), vDirection(Z), "
 680            << "Magnitude, "
 681            << "vTurbPQR(P), vTurbPQR(Q), vTurbPQR(R), " << endl;
 682     }
 683     if (from == 2) {
 684       cout << vTurbulenceNED << ", " << vTurbulenceGrad << ", " << vDirection << ", " << Magnitude << ", " << vTurbPQR << endl;
 685     }
 686   }
 687   if (debug_lvl & 64) {
 688     if (from == 0) { // Constructor
 689       cout << IdSrc << endl;
 690       cout << IdHdr << endl;
 691     }
 692   }
 693 }
 694
 695 } // namespace JSBSim