src/FDM/JSBSim/models/FGAtmosphere.cpp

   1 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   2
   3  Module:       FGAtmosphere.cpp
   4  Author:       Jon Berndt, Tony Peden
   5  Date started: 6/2011
   6  Purpose:      Models an atmosphere interface class
   7  Called by:    FGFDMExec
   8
   9  ------------- Copyright (C) 2011  Jon S. Berndt (jon@jsbsim.org) -------------
  10
  11  This program is free software; you can redistribute it and/or modify it under
  12  the terms of the GNU Lesser General Public License as published by the Free Software
  13  Foundation; either version 2 of the License, or (at your option) any later
  14  version.
  15
  16  This program is distributed in the hope that it will be useful, but WITHOUT
  17  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  18  FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
  19  details.
  20
  21  You should have received a copy of the GNU Lesser General Public License along with
  22  this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  23  Place - Suite 330, Boston, MA  02111-1307, USA.
  24
  25  Further information about the GNU Lesser General Public License can also be found on
  26  the world wide web at http://www.gnu.org.
  27
  28 FUNCTIONAL DESCRIPTION
  29 --------------------------------------------------------------------------------
  30 This models a base atmosphere class to serve as a common interface to any derived
  31 atmosphere models.
  32
  33 HISTORY
  34 --------------------------------------------------------------------------------
  35 6/18/2011 Started Jon S. Berndt
  36
  37 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  38 COMMENTS, REFERENCES,  and NOTES
  39 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  40
  41 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  42 INCLUDES
  43 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  44
  45 #include <iostream>
  46 #include <iomanip>
  47 #include <cstdlib>
  48 #include "FGFDMExec.h"
  49 #include "FGAtmosphere.h"
  50
  51 namespace JSBSim {
  52
  53 static const char *IdSrc = "$Id: FGAtmosphere.cpp,v 1.51 2012/04/13 13:18:28 jberndt Exp $";
  54 static const char *IdHdr = ID_ATMOSPHERE;
  55
  56 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  57 CLASS IMPLEMENTATION
  58 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  59
  60 FGAtmosphere::FGAtmosphere(FGFDMExec* fdmex) : FGModel(fdmex),
  61                                                PressureAltitude(0.0),      // ft
  62                                                DensityAltitude(0.0),       // ft
  63                                                SutherlandConstant(198.72), // deg Rankine
  64                                                Beta(2.269690E-08)          // slug/(sec ft R^0.5)
  65 {
  66   Name = "FGAtmosphere";
  67
  68   bind();
  69   Debug(0);
  70 }
  71
  72 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  73
  74 FGAtmosphere::~FGAtmosphere()
  75 {
  76   Debug(1);
  77 }
  78
  79 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  80
  81 bool FGAtmosphere::InitModel(void)
  82 {
  83   Calculate(0.0);
  84   SLtemperature = Temperature = 518.67;
  85   SLpressure = Pressure = 2116.22;
  86   SLdensity = Density = Pressure/(Reng*Temperature);
  87   SLsoundspeed = Soundspeed = sqrt(SHRatio*Reng*(Temperature));
  88
  89   rSLtemperature = 1/SLtemperature ;
  90   rSLpressure    = 1/SLpressure    ;
  91   rSLdensity     = 1/SLdensity     ;
  92   rSLsoundspeed  = 1/SLsoundspeed  ;
  93
  94   return true;
  95 }
  96
  97 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  98
  99 bool FGAtmosphere::Run(bool Holding)
 100 {
 101   if (FGModel::Run(Holding)) return true;
 102   if (Holding) return false;
 103
 104   Calculate(in.altitudeASL);
 105
 106   Debug(2);
 107   return false;
 108 }
 109
 110 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 111
 112 void FGAtmosphere::Calculate(double altitude)
 113 {
 114   Temperature = GetTemperature(altitude);
 115   Pressure    = GetPressure(altitude);
 116   Density     = Pressure/(Reng*Temperature);
 117   Soundspeed  = sqrt(SHRatio*Reng*(Temperature));
 118   PressureAltitude = altitude;
 119   DensityAltitude = altitude;
 120
 121   Viscosity = Beta * pow(Temperature, 1.5) / (SutherlandConstant + Temperature);
 122   KinematicViscosity = Viscosity / Density;
 123 }
 124
 125 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 126
 127 void FGAtmosphere::SetPressureSL(ePressure unit, double pressure)
 128 {
 129   double press = ConvertToPSF(pressure, unit);
 130
 131   SLpressure = press;
 132 }
 133
 134 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 135 // Get the modeled density at a specified altitude
 136
 137 double FGAtmosphere::GetDensity(double altitude) const
 138 {
 139   return GetPressure(altitude)/(Reng * GetTemperature(altitude));
 140 }
 141
 142 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 143 // This function sets the sea level temperature.
 144 // Internally, the Rankine scale is used for calculations, so any temperature
 145 // supplied must be converted to that unit.
 146
 147 void FGAtmosphere::SetTemperatureSL(double t, eTemperature unit)
 148 {
 149   SLtemperature = ConvertToRankine(t, unit);
 150 }
 151
 152 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 153
 154 double FGAtmosphere::ConvertToRankine(double t, eTemperature unit) const
 155 {
 156   double targetTemp=0; // in degrees Rankine
 157
 158   switch(unit) {
 159   case eFahrenheit:
 160     targetTemp = t + 459.67;
 161     break;
 162   case eCelsius:
 163     targetTemp = t*9.0/5.0 + 32.0 + 459.67;
 164     break;
 165   case eRankine:
 166     targetTemp = t;
 167     break;
 168   case eKelvin:
 169     targetTemp = t*9.0/5.0;
 170     break;
 171   default:
 172     break;
 173   }
 174
 175   return targetTemp;
 176 }
 177
 178 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 179
 180 double FGAtmosphere::ConvertToPSF(double p, ePressure unit) const
 181 {
 182   double targetPressure=0; // Pressure in PSF
 183
 184   switch(unit) {
 185   case ePSF:
 186     targetPressure = p;
 187     break;
 188   case eMillibars:
 189     targetPressure = p*2.08854342;
 190     break;
 191   case ePascals:
 192     targetPressure = p*0.0208854342;
 193     break;
 194   case eInchesHg:
 195     targetPressure = p*70.7180803;
 196     break;
 197   default:
 198     throw("Undefined pressure unit given");
 199   }
 200
 201   return targetPressure;
 202 }
 203
 204 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 205
 206 void FGAtmosphere::bind(void)
 207 {
 208   typedef double (FGAtmosphere::*PMFi)(int) const;
 209   typedef void (FGAtmosphere::*PMF)(int, double);
 210   PropertyManager->Tie("atmosphere/T-R", this, &FGAtmosphere::GetTemperature);
 211   PropertyManager->Tie("atmosphere/rho-slugs_ft3", this, &FGAtmosphere::GetDensity);
 212   PropertyManager->Tie("atmosphere/P-psf", this, &FGAtmosphere::GetPressure);
 213   PropertyManager->Tie("atmosphere/a-fps", this, &FGAtmosphere::GetSoundSpeed);
 214   PropertyManager->Tie("atmosphere/T-sl-R", this, &FGAtmosphere::GetTemperatureSL);
 215   PropertyManager->Tie("atmosphere/rho-sl-slugs_ft3", this, &FGAtmosphere::GetDensitySL);
 216 //  PropertyManager->Tie("atmosphere/P-sl-psf", this, ePSF,
 217 //                                   (PMFi)&FGAtmosphere::GetPressureSL,
 218 //                                   (PMF)&FGAtmosphere::SetPressureSL);
 219   PropertyManager->Tie("atmosphere/a-sl-fps", this, &FGAtmosphere::GetSoundSpeedSL);
 220   PropertyManager->Tie("atmosphere/theta", this, &FGAtmosphere::GetTemperatureRatio);
 221   PropertyManager->Tie("atmosphere/sigma", this, &FGAtmosphere::GetDensityRatio);
 222   PropertyManager->Tie("atmosphere/delta", this, &FGAtmosphere::GetPressureRatio);
 223   PropertyManager->Tie("atmosphere/a-ratio", this, &FGAtmosphere::GetSoundSpeedRatio);
 224   PropertyManager->Tie("atmosphere/density-altitude", this, &FGAtmosphere::GetDensityAltitude);
 225   PropertyManager->Tie("atmosphere/pressure-altitude", this, &FGAtmosphere::GetPressureAltitude);
 226 }
 227
 228 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 229 //    The bitmasked value choices are as follows:
 230 //    unset: In this case (the default) JSBSim would only print
 231 //       out the normally expected messages, essentially echoing
 232 //       the config files as they are read. If the environment
 233 //       variable is not set, debug_lvl is set to 1 internally
 234 //    0: This requests JSBSim not to output any messages
 235 //       whatsoever.
 236 //    1: This value explicity requests the normal JSBSim
 237 //       startup messages
 238 //    2: This value asks for a message to be printed out when
 239 //       a class is instantiated
 240 //    4: When this value is set, a message is displayed when a
 241 //       FGModel object executes its Run() method
 242 //    8: When this value is set, various runtime state variables
 243 //       are printed out periodically
 244 //    16: When set various parameters are sanity checked and
 245 //       a message is printed out when they go out of bounds
 246
 247 void FGAtmosphere::Debug(int from)
 248 {
 249   if (debug_lvl <= 0) return;
 250
 251   if (debug_lvl & 1) { // Standard console startup message output
 252     if (from == 0) { // Constructor
 253     }
 254   }
 255   if (debug_lvl & 2 ) { // Instantiation/Destruction notification
 256     if (from == 0) std::cout << "Instantiated: FGAtmosphere" << std::endl;
 257     if (from == 1) std::cout << "Destroyed:    FGAtmosphere" << std::endl;
 258   }
 259   if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
 260   }
 261   if (debug_lvl & 8 ) { // Runtime state variables
 262   }
 263   if (debug_lvl & 16) { // Sanity checking
 264   }
 265   if (debug_lvl & 128) { //
 266   }
 267   if (debug_lvl & 64) {
 268     if (from == 0) { // Constructor
 269       std::cout << IdSrc << std::endl;
 270       std::cout << IdHdr << std::endl;
 271     }
 272   }
 273 }
 274
 275 } // namespace JSBSim