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 1.49 2011/09/11 11:36:04 bcoconni 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   RunPreFunctions();
 105
 106   Calculate(in.altitudeASL);
 107
 108   RunPostFunctions();
 109
 110   Debug(2);
 111   return false;
 112 }
 113
 114 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 115
 116 void FGAtmosphere::Calculate(double altitude)
 117 {
 118   Temperature = GetTemperature(altitude);
 119   Pressure    = GetPressure(altitude);
 120   Density     = Pressure/(Reng*Temperature);
 121   Soundspeed  = sqrt(SHRatio*Reng*(Temperature));
 122   PressureAltitude = altitude;
 123   DensityAltitude = altitude;
 124
 125   Viscosity = Beta * pow(Temperature, 1.5) / (SutherlandConstant + Temperature);
 126   KinematicViscosity = Viscosity / Density;
 127 }
 128
 129 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 130
 131 void FGAtmosphere::SetPressureSL(double pressure, ePressure unit)
 132 {
 133   double press = ConvertToPSF(pressure, unit);
 134
 135   SLpressure = press;
 136 }
 137
 138 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 139 // Get the modeled density at a specified altitude
 140
 141 double FGAtmosphere::GetDensity(double altitude) const
 142 {
 143   return GetPressure(altitude)/(Reng * GetTemperature(altitude));
 144 }
 145
 146 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 147 // This function sets the sea level temperature.
 148 // Internally, the Rankine scale is used for calculations, so any temperature
 149 // supplied must be converted to that unit.
 150
 151 void FGAtmosphere::SetTemperatureSL(double t, eTemperature unit)
 152 {
 153   SLtemperature = ConvertToRankine(t, unit);
 154 }
 155
 156 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 157
 158 double FGAtmosphere::ConvertToRankine(double t, eTemperature unit) const
 159 {
 160   double targetTemp=0; // in degrees Rankine
 161
 162   switch(unit) {
 163   case eFahrenheit:
 164     targetTemp = t + 459.67;
 165     break;
 166   case eCelsius:
 167     targetTemp = t*9.0/5.0 + 32.0 + 459.67;
 168     break;
 169   case eRankine:
 170     targetTemp = t;
 171     break;
 172   case eKelvin:
 173     targetTemp = t*9.0/5.0;
 174     break;
 175   default:
 176     break;
 177   }
 178
 179   return targetTemp;
 180 }
 181
 182 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 183
 184 double FGAtmosphere::ConvertToPSF(double p, ePressure unit) const
 185 {
 186   double targetPressure=0; // Pressure in PSF
 187
 188   switch(unit) {
 189   case ePSF:
 190     targetPressure = p;
 191     break;
 192   case eMillibars:
 193     targetPressure = p*2.08854342;
 194     break;
 195   case ePascals:
 196     targetPressure = p*0.0208854342;
 197     break;
 198   case eInchesHg:
 199     targetPressure = p*70.7180803;
 200     break;
 201   default:
 202     throw("Undefined pressure unit given");
 203   }
 204
 205   return targetPressure;
 206 }
 207
 208 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 209
 210 void FGAtmosphere::bind(void)
 211 {
 212   typedef double (FGAtmosphere::*PMFi)(int) const;
 213   typedef void (FGAtmosphere::*PMF)(int, double);
 214   PropertyManager->Tie("atmosphere/T-R", this, &FGAtmosphere::GetTemperature);
 215   PropertyManager->Tie("atmosphere/rho-slugs_ft3", this, &FGAtmosphere::GetDensity);
 216   PropertyManager->Tie("atmosphere/P-psf", this, &FGAtmosphere::GetPressure);
 217   PropertyManager->Tie("atmosphere/a-fps", this, &FGAtmosphere::GetSoundSpeed);
 218   PropertyManager->Tie("atmosphere/T-sl-R", this, &FGAtmosphere::GetTemperatureSL);
 219   PropertyManager->Tie("atmosphere/rho-sl-slugs_ft3", this, &FGAtmosphere::GetDensitySL);
 220   PropertyManager->Tie("atmosphere/P-sl-psf", this, &FGAtmosphere::GetPressureSL);
 221   PropertyManager->Tie("atmosphere/a-sl-fps", this, &FGAtmosphere::GetSoundSpeedSL);
 222   PropertyManager->Tie("atmosphere/theta", this, &FGAtmosphere::GetTemperatureRatio);
 223   PropertyManager->Tie("atmosphere/sigma", this, &FGAtmosphere::GetDensityRatio);
 224   PropertyManager->Tie("atmosphere/delta", this, &FGAtmosphere::GetPressureRatio);
 225   PropertyManager->Tie("atmosphere/a-ratio", this, &FGAtmosphere::GetSoundSpeedRatio);
 226   PropertyManager->Tie("atmosphere/density-altitude", this, &FGAtmosphere::GetDensityAltitude);
 227   PropertyManager->Tie("atmosphere/pressure-altitude", this, &FGAtmosphere::GetPressureAltitude);
 228 }
 229
 230 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 231 //    The bitmasked value choices are as follows:
 232 //    unset: In this case (the default) JSBSim would only print
 233 //       out the normally expected messages, essentially echoing
 234 //       the config files as they are read. If the environment
 235 //       variable is not set, debug_lvl is set to 1 internally
 236 //    0: This requests JSBSim not to output any messages
 237 //       whatsoever.
 238 //    1: This value explicity requests the normal JSBSim
 239 //       startup messages
 240 //    2: This value asks for a message to be printed out when
 241 //       a class is instantiated
 242 //    4: When this value is set, a message is displayed when a
 243 //       FGModel object executes its Run() method
 244 //    8: When this value is set, various runtime state variables
 245 //       are printed out periodically
 246 //    16: When set various parameters are sanity checked and
 247 //       a message is printed out when they go out of bounds
 248
 249 void FGAtmosphere::Debug(int from)
 250 {
 251   if (debug_lvl <= 0) return;
 252
 253   if (debug_lvl & 1) { // Standard console startup message output
 254     if (from == 0) { // Constructor
 255     }
 256   }
 257   if (debug_lvl & 2 ) { // Instantiation/Destruction notification
 258     if (from == 0) std::cout << "Instantiated: FGAtmosphere" << std::endl;
 259     if (from == 1) std::cout << "Destroyed:    FGAtmosphere" << std::endl;
 260   }
 261   if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
 262   }
 263   if (debug_lvl & 8 ) { // Runtime state variables
 264   }
 265   if (debug_lvl & 16) { // Sanity checking
 266   }
 267   if (debug_lvl & 128) { //
 268   }
 269   if (debug_lvl & 64) {
 270     if (from == 0) { // Constructor
 271       std::cout << IdSrc << std::endl;
 272       std::cout << IdHdr << std::endl;
 273     }
 274   }
 275 }
 276
 277 } // namespace JSBSim