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 "FGAircraft.h"
  52 #include "FGPropagate.h"
  53 #include "FGInertial.h"
  54 #include "FGAuxiliary.h"
  55 #include "FGFDMExec.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: FGAtmosphere.cpp,v 1.35 2010/08/11 11:51:33 jberndt Exp $";
  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
 281   if (T_dev == 0.0) density_altitude = h;
 282   else              density_altitude = 518.4/0.00357 * (1.0 - pow(GetDensityRatio(),0.235));
 283
 284   if (turbType != ttNone) Turbulence();
 285
 286   vTotalWindNED = vWindNED + vGustNED + vTurbulenceNED;
 287
 288    // psiw (Wind heading) is the direction the wind is blowing towards
 289   if (vWindNED(eX) != 0.0) psiw = atan2( vWindNED(eY), vWindNED(eX) );
 290   if (psiw < 0) psiw += 2*M_PI;
 291
 292   soundspeed = sqrt(SHRatio*Reng*(*temperature));
 293
 294   intViscosity = Beta * pow(intTemperature, 1.5) / (SutherlandConstant + intTemperature);
 295   intKinematicViscosity = intViscosity / intDensity;
 296 }
 297
 298
 299 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 300 // Get the standard atmospheric properties at a specified altitude
 301
 302 void FGAtmosphere::GetStdAtmosphere(double altitude) {
 303   StandardTempOnly = true;
 304   Calculate(altitude);
 305   StandardTempOnly = false;
 306   atmosphere.Temperature = intTemperature;
 307   atmosphere.Pressure = intPressure;
 308   atmosphere.Density = intDensity;
 309
 310   // Reset the internal atmospheric state
 311   Calculate(h);
 312 }
 313
 314 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 315 // Get the standard pressure at a specified altitude
 316
 317 double FGAtmosphere::GetPressure(double altitude) {
 318   GetStdAtmosphere(altitude);
 319   return atmosphere.Pressure;
 320 }
 321
 322 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 323 // Get the standard temperature at a specified altitude
 324
 325 double FGAtmosphere::GetTemperature(double altitude) {
 326   GetStdAtmosphere(altitude);
 327   return atmosphere.Temperature;
 328 }
 329
 330 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 331 // Get the standard density at a specified altitude
 332
 333 double FGAtmosphere::GetDensity(double altitude) {
 334   GetStdAtmosphere(altitude);
 335   return atmosphere.Density;
 336 }
 337
 338
 339 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 340 // square a value, but preserve the original sign
 341
 342 static inline double square_signed (double value)
 343 {
 344     if (value < 0)
 345         return value * value * -1;
 346     else
 347         return value * value;
 348 }
 349
 350 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 351 //
 352 // psi is the angle that the wind is blowing *towards*
 353
 354 void FGAtmosphere::SetWindspeed(double speed)
 355 {
 356   if (vWindNED.Magnitude() == 0.0) {
 357     psiw = 0.0;
 358     vWindNED(eNorth) = speed;
 359   } else {
 360     vWindNED(eNorth) = speed * cos(psiw);
 361     vWindNED(eEast) = speed * sin(psiw);
 362     vWindNED(eDown) = 0.0;
 363   }
 364 }
 365
 366 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 367
 368 double FGAtmosphere::GetWindspeed(void) const
 369 {
 370   return vWindNED.Magnitude();
 371 }
 372
 373 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 374 //
 375 // psi is the angle that the wind is blowing *towards*
 376
 377 void FGAtmosphere::SetWindPsi(double dir)
 378 {
 379   double mag = GetWindspeed();
 380   psiw = dir;
 381   SetWindspeed(mag);
 382 }
 383
 384 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 385
 386 void FGAtmosphere::Turbulence(void)
 387 {
 388   double DeltaT = rate*FDMExec->GetDeltaT();
 389
 390   switch (turbType) {
 391   case ttStandard: {
 392     // TurbGain = TurbGain * TurbGain * 100.0; // what is this!?
 393
 394     vDirectiondAccelDt(eX) = 1 - 2.0*(double(rand())/double(RAND_MAX));
 395     vDirectiondAccelDt(eY) = 1 - 2.0*(double(rand())/double(RAND_MAX));
 396     vDirectiondAccelDt(eZ) = 1 - 2.0*(double(rand())/double(RAND_MAX));
 397
 398     MagnitudedAccelDt = 1 - 2.0*(double(rand())/double(RAND_MAX)) - Magnitude;
 399                                 // Scale the magnitude so that it moves
 400                                 // away from the peaks
 401     MagnitudedAccelDt = ((MagnitudedAccelDt - Magnitude) /
 402                          (1 + fabs(Magnitude)));
 403     MagnitudeAccel    += MagnitudedAccelDt*TurbRate*DeltaT;
 404     Magnitude         += MagnitudeAccel*DeltaT;
 405     Magnitude          = fabs(Magnitude);
 406
 407     vDirectiondAccelDt.Normalize();
 408
 409                                 // deemphasise non-vertical forces
 410     vDirectiondAccelDt(eX) = square_signed(vDirectiondAccelDt(eX));
 411     vDirectiondAccelDt(eY) = square_signed(vDirectiondAccelDt(eY));
 412
 413     vDirectionAccel += vDirectiondAccelDt*TurbRate*DeltaT;
 414     vDirectionAccel.Normalize();
 415     vDirection      += vDirectionAccel*DeltaT;
 416
 417     vDirection.Normalize();
 418
 419                                 // Diminish turbulence within three wingspans
 420                                 // of the ground
 421     vTurbulenceNED = TurbGain * Magnitude * vDirection;
 422     double HOverBMAC = Auxiliary->GetHOverBMAC();
 423     if (HOverBMAC < 3.0)
 424         vTurbulenceNED *= (HOverBMAC / 3.0) * (HOverBMAC / 3.0);
 425
 426     // I don't believe these next two statements calculate the proper gradient over
 427     // the aircraft body. One reason is because this has no relationship with the
 428     // orientation or velocity of the aircraft, which it must have. What is vTurbulenceGrad
 429     // supposed to represent? And the direction and magnitude of the turbulence can change,
 430     // so both accelerations need to be accounted for, no?
 431
 432     // Need to determine the turbulence change in body axes between two time points.
 433
 434     vTurbulenceGrad = TurbGain*MagnitudeAccel * vDirection;
 435     vBodyTurbGrad = Propagate->GetTl2b()*vTurbulenceGrad;
 436
 437     if (Aircraft->GetWingSpan() > 0) {
 438       vTurbPQR(eP) = vBodyTurbGrad(eY)/Aircraft->GetWingSpan();
 439     } else {
 440       vTurbPQR(eP) = vBodyTurbGrad(eY)/30.0;
 441     }
 442 //     if (Aircraft->GetHTailArm() != 0.0)
 443 //       vTurbPQR(eQ) = vBodyTurbGrad(eZ)/Aircraft->GetHTailArm();
 444 //     else
 445 //       vTurbPQR(eQ) = vBodyTurbGrad(eZ)/10.0;
 446
 447     if (Aircraft->GetVTailArm() > 0)
 448       vTurbPQR(eR) = vBodyTurbGrad(eX)/Aircraft->GetVTailArm();
 449     else
 450       vTurbPQR(eR) = vBodyTurbGrad(eX)/10.0;
 451
 452                                 // Clear the horizontal forces
 453                                 // actually felt by the plane, now
 454                                 // that we've used them to calculate
 455                                 // moments.
 456                                 // Why? (JSB)
 457 //    vTurbulenceNED(eX) = 0.0;
 458 //    vTurbulenceNED(eY) = 0.0;
 459
 460     break;
 461   }
 462   case ttBerndt: { // This is very experimental and incomplete at the moment.
 463
 464     vDirectiondAccelDt(eX) = GaussianRandomNumber();
 465     vDirectiondAccelDt(eY) = GaussianRandomNumber();
 466     vDirectiondAccelDt(eZ) = GaussianRandomNumber();
 467 /*
 468     MagnitudedAccelDt = GaussianRandomNumber();
 469     MagnitudeAccel    += MagnitudedAccelDt * DeltaT;
 470     Magnitude         += MagnitudeAccel * DeltaT;
 471 */
 472     Magnitude         += GaussianRandomNumber() * DeltaT;
 473
 474     vDirectiondAccelDt.Normalize();
 475     vDirectionAccel += TurbRate * vDirectiondAccelDt * DeltaT;
 476     vDirectionAccel.Normalize();
 477     vDirection      += vDirectionAccel*DeltaT;
 478
 479     // Diminish z-vector within two wingspans of the ground
 480     double HOverBMAC = Auxiliary->GetHOverBMAC();
 481     if (HOverBMAC < 2.0) vDirection(eZ) *= HOverBMAC / 2.0;
 482
 483     vDirection.Normalize();
 484
 485     vTurbulenceNED = TurbGain*Magnitude * vDirection;
 486     vTurbulenceGrad = TurbGain*MagnitudeAccel * vDirection;
 487
 488     vBodyTurbGrad = Propagate->GetTl2b() * vTurbulenceGrad;
 489     vTurbPQR(eP) = vBodyTurbGrad(eY) / Aircraft->GetWingSpan();
 490     if (Aircraft->GetHTailArm() > 0)
 491       vTurbPQR(eQ) = vBodyTurbGrad(eZ) / Aircraft->GetHTailArm();
 492     else
 493       vTurbPQR(eQ) = vBodyTurbGrad(eZ) / 10.0;
 494
 495     if (Aircraft->GetVTailArm() > 0)
 496       vTurbPQR(eR) = vBodyTurbGrad(eX) / Aircraft->GetVTailArm();
 497     else
 498       vTurbPQR(eR) = vBodyTurbGrad(eX)/10.0;
 499
 500     break;
 501   }
 502   case ttCulp: {
 503
 504     vTurbPQR(eP) = wind_from_clockwise;
 505     if (TurbGain == 0.0) return;
 506
 507     // keep the inputs within allowable limts for this model
 508     if (TurbGain < 0.0) TurbGain = 0.0;
 509     if (TurbGain > 1.0) TurbGain = 1.0;
 510     if (TurbRate < 0.0) TurbRate = 0.0;
 511     if (TurbRate > 30.0) TurbRate = 30.0;
 512     if (Rhythmicity < 0.0) Rhythmicity = 0.0;
 513     if (Rhythmicity > 1.0) Rhythmicity = 1.0;
 514
 515     // generate a sine wave corresponding to turbulence rate in hertz
 516     double time = FDMExec->GetSimTime();
 517     double sinewave = sin( time * TurbRate * 6.283185307 );
 518
 519     double random = 0.0;
 520     if (target_time == 0.0) {
 521       strength = random = 1 - 2.0*(double(rand())/double(RAND_MAX));
 522       target_time = time + 0.71 + (random * 0.5);
 523     }
 524     if (time > target_time) {
 525       spike = 1.0;
 526       target_time = 0.0;
 527     }
 528
 529     // max vertical wind speed in fps, corresponds to TurbGain = 1.0
 530     double max_vs = 40;
 531
 532     vTurbulenceNED(1) = vTurbulenceNED(2) = vTurbulenceNED(3) = 0.0;
 533     double delta = strength * max_vs * TurbGain * (1-Rhythmicity) * spike;
 534
 535     // Vertical component of turbulence.
 536     vTurbulenceNED(3) = sinewave * max_vs * TurbGain * Rhythmicity;
 537     vTurbulenceNED(3)+= delta;
 538     double HOverBMAC = Auxiliary->GetHOverBMAC();
 539     if (HOverBMAC < 3.0)
 540         vTurbulenceNED(3) *= HOverBMAC * 0.3333;
 541
 542     // Yaw component of turbulence.
 543     vTurbulenceNED(1) = sin( delta * 3.0 );
 544     vTurbulenceNED(2) = cos( delta * 3.0 );
 545
 546     // Roll component of turbulence. Clockwise vortex causes left roll.
 547     vTurbPQR(eP) += delta * 0.04;
 548
 549     spike = spike * 0.9;
 550     break;
 551   }
 552   default:
 553     break;
 554   }
 555 }
 556
 557 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 558
 559 void FGAtmosphere::UseExternal(void)
 560 {
 561   temperature=&exTemperature;
 562   pressure=&exPressure;
 563   density=&exDensity;
 564   useExternal=true;
 565 }
 566
 567 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 568
 569 void FGAtmosphere::UseInternal(void)
 570 {
 571   temperature=&intTemperature;
 572   pressure=&intPressure;
 573   density=&intDensity;
 574   useExternal=false;
 575 }
 576
 577 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 578
 579 void FGAtmosphere::bind(void)
 580 {
 581   typedef double (FGAtmosphere::*PMF)(int) const;
 582   typedef double (FGAtmosphere::*PMFv)(void) const;
 583   typedef int (FGAtmosphere::*PMFt)(void) const;
 584   typedef void   (FGAtmosphere::*PMFd)(int,double);
 585   typedef void   (FGAtmosphere::*PMFi)(int);
 586   PropertyManager->Tie("atmosphere/T-R", this, (PMFv)&FGAtmosphere::GetTemperature);
 587   PropertyManager->Tie("atmosphere/rho-slugs_ft3", this, (PMFv)&FGAtmosphere::GetDensity);
 588   PropertyManager->Tie("atmosphere/P-psf", this, (PMFv)&FGAtmosphere::GetPressure);
 589   PropertyManager->Tie("atmosphere/a-fps", this, &FGAtmosphere::GetSoundSpeed);
 590   PropertyManager->Tie("atmosphere/T-sl-R", this, &FGAtmosphere::GetTemperatureSL);
 591   PropertyManager->Tie("atmosphere/rho-sl-slugs_ft3", this, &FGAtmosphere::GetDensitySL);
 592   PropertyManager->Tie("atmosphere/P-sl-psf", this, &FGAtmosphere::GetPressureSL);
 593   PropertyManager->Tie("atmosphere/a-sl-fps", this, &FGAtmosphere::GetSoundSpeedSL);
 594   PropertyManager->Tie("atmosphere/theta", this, &FGAtmosphere::GetTemperatureRatio);
 595   PropertyManager->Tie("atmosphere/sigma", this, &FGAtmosphere::GetDensityRatio);
 596   PropertyManager->Tie("atmosphere/delta", this, &FGAtmosphere::GetPressureRatio);
 597   PropertyManager->Tie("atmosphere/a-ratio", this, &FGAtmosphere::GetSoundSpeedRatio);
 598   PropertyManager->Tie("atmosphere/psiw-rad", this, &FGAtmosphere::GetWindPsi, &FGAtmosphere::SetWindPsi);
 599   PropertyManager->Tie("atmosphere/delta-T", this, &FGAtmosphere::GetDeltaT, &FGAtmosphere::SetDeltaT);
 600   PropertyManager->Tie("atmosphere/T-sl-dev-F", this, &FGAtmosphere::GetSLTempDev, &FGAtmosphere::SetSLTempDev);
 601   PropertyManager->Tie("atmosphere/density-altitude", this, &FGAtmosphere::GetDensityAltitude);
 602
 603   PropertyManager->Tie("atmosphere/wind-north-fps", this, eNorth, (PMF)&FGAtmosphere::GetWindNED,
 604                                                           (PMFd)&FGAtmosphere::SetWindNED);
 605   PropertyManager->Tie("atmosphere/wind-east-fps",  this, eEast, (PMF)&FGAtmosphere::GetWindNED,
 606                                                           (PMFd)&FGAtmosphere::SetWindNED);
 607   PropertyManager->Tie("atmosphere/wind-down-fps",  this, eDown, (PMF)&FGAtmosphere::GetWindNED,
 608                                                           (PMFd)&FGAtmosphere::SetWindNED);
 609   PropertyManager->Tie("atmosphere/wind-mag-fps", this, &FGAtmosphere::GetWindspeed,
 610                                                         &FGAtmosphere::SetWindspeed);
 611   PropertyManager->Tie("atmosphere/total-wind-north-fps", this, eNorth, (PMF)&FGAtmosphere::GetTotalWindNED);
 612   PropertyManager->Tie("atmosphere/total-wind-east-fps",  this, eEast,  (PMF)&FGAtmosphere::GetTotalWindNED);
 613   PropertyManager->Tie("atmosphere/total-wind-down-fps",  this, eDown,  (PMF)&FGAtmosphere::GetTotalWindNED);
 614
 615   PropertyManager->Tie("atmosphere/gust-north-fps", this, eNorth, (PMF)&FGAtmosphere::GetGustNED,
 616                                                           (PMFd)&FGAtmosphere::SetGustNED);
 617   PropertyManager->Tie("atmosphere/gust-east-fps",  this, eEast, (PMF)&FGAtmosphere::GetGustNED,
 618                                                           (PMFd)&FGAtmosphere::SetGustNED);
 619   PropertyManager->Tie("atmosphere/gust-down-fps",  this, eDown, (PMF)&FGAtmosphere::GetGustNED,
 620                                                           (PMFd)&FGAtmosphere::SetGustNED);
 621
 622   PropertyManager->Tie("atmosphere/turb-north-fps", this, eNorth, (PMF)&FGAtmosphere::GetTurbNED,
 623                                                           (PMFd)&FGAtmosphere::SetTurbNED);
 624   PropertyManager->Tie("atmosphere/turb-east-fps",  this, eEast, (PMF)&FGAtmosphere::GetTurbNED,
 625                                                           (PMFd)&FGAtmosphere::SetTurbNED);
 626   PropertyManager->Tie("atmosphere/turb-down-fps",  this, eDown, (PMF)&FGAtmosphere::GetTurbNED,
 627                                                           (PMFd)&FGAtmosphere::SetTurbNED);
 628
 629   PropertyManager->Tie("atmosphere/p-turb-rad_sec", this,1, (PMF)&FGAtmosphere::GetTurbPQR);
 630   PropertyManager->Tie("atmosphere/q-turb-rad_sec", this,2, (PMF)&FGAtmosphere::GetTurbPQR);
 631   PropertyManager->Tie("atmosphere/r-turb-rad_sec", this,3, (PMF)&FGAtmosphere::GetTurbPQR);
 632   PropertyManager->Tie("atmosphere/turb-type", this, (PMFt)&FGAtmosphere::GetTurbType, (PMFi)&FGAtmosphere::SetTurbType);
 633   PropertyManager->Tie("atmosphere/turb-rate", this, &FGAtmosphere::GetTurbRate, &FGAtmosphere::SetTurbRate);
 634   PropertyManager->Tie("atmosphere/turb-gain", this, &FGAtmosphere::GetTurbGain, &FGAtmosphere::SetTurbGain);
 635   PropertyManager->Tie("atmosphere/turb-rhythmicity", this, &FGAtmosphere::GetRhythmicity,
 636                                                             &FGAtmosphere::SetRhythmicity);
 637 }
 638
 639 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 640 //    The bitmasked value choices are as follows:
 641 //    unset: In this case (the default) JSBSim would only print
 642 //       out the normally expected messages, essentially echoing
 643 //       the config files as they are read. If the environment
 644 //       variable is not set, debug_lvl is set to 1 internally
 645 //    0: This requests JSBSim not to output any messages
 646 //       whatsoever.
 647 //    1: This value explicity requests the normal JSBSim
 648 //       startup messages
 649 //    2: This value asks for a message to be printed out when
 650 //       a class is instantiated
 651 //    4: When this value is set, a message is displayed when a
 652 //       FGModel object executes its Run() method
 653 //    8: When this value is set, various runtime state variables
 654 //       are printed out periodically
 655 //    16: When set various parameters are sanity checked and
 656 //       a message is printed out when they go out of bounds
 657
 658 void FGAtmosphere::Debug(int from)
 659 {
 660   if (debug_lvl <= 0) return;
 661
 662   if (debug_lvl & 1) { // Standard console startup message output
 663     if (from == 0) { // Constructor
 664     }
 665   }
 666   if (debug_lvl & 2 ) { // Instantiation/Destruction notification
 667     if (from == 0) cout << "Instantiated: FGAtmosphere" << endl;
 668     if (from == 1) cout << "Destroyed:    FGAtmosphere" << endl;
 669   }
 670   if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
 671   }
 672   if (debug_lvl & 8 ) { // Runtime state variables
 673   }
 674   if (debug_lvl & 16) { // Sanity checking
 675   }
 676   if (debug_lvl & 128) { // Turbulence
 677     if (first_pass && from == 2) {
 678       first_pass = false;
 679       cout << "vTurbulenceNED(X), vTurbulenceNED(Y), vTurbulenceNED(Z), "
 680            << "vTurbulenceGrad(X), vTurbulenceGrad(Y), vTurbulenceGrad(Z), "
 681            << "vDirection(X), vDirection(Y), vDirection(Z), "
 682            << "Magnitude, "
 683            << "vTurbPQR(P), vTurbPQR(Q), vTurbPQR(R), " << endl;
 684     }
 685     if (from == 2) {
 686       cout << vTurbulenceNED << ", " << vTurbulenceGrad << ", " << vDirection << ", " << Magnitude << ", " << vTurbPQR << endl;
 687     }
 688   }
 689   if (debug_lvl & 64) {
 690     if (from == 0) { // Constructor
 691       cout << IdSrc << endl;
 692       cout << IdHdr << endl;
 693     }
 694   }
 695 }
 696
 697 } // namespace JSBSim