/***************************************************************************** Module: FGPhysicalProperties.cpp Author: Christian Mayer Date started: 28.05.99 Called by: main program -------- Copyright (C) 1999 Christian Mayer (fgfs@christianmayer.de) -------- This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. Further information about the GNU General Public License can also be found on the world wide web at http://www.gnu.org. FUNCTIONAL DESCRIPTION ------------------------------------------------------------------------------ Initialice the FGPhysicalProperties struct to something sensible(?) HISTORY ------------------------------------------------------------------------------ 29.05.1999 Christian Mayer Created 16.06.1999 Durk Talsma Portability for Linux 20.06.1999 Christian Mayer added lots of consts 11.10.1999 Christian Mayer changed set<> to map<> on Bernie Bright's suggestion 19.10.1999 Christian Mayer change to use PLIB's sg instead of Point[2/3]D and lots of wee code cleaning *****************************************************************************/ /****************************************************************************/ /* INCLUDES */ /****************************************************************************/ #include "FGPhysicalProperties.h" #include "FGWeatherDefs.h" #include "FGWeatherUtils.h" /****************************************************************************/ /********************************** CODE ************************************/ /****************************************************************************/ FGPhysicalProperties::FGPhysicalProperties() { sgVec3 zero; sgZeroVec3( zero ); /************************************************************************/ /* This standart constructor fills the class with a standard weather */ /************************************************************************/ Wind[-1000.0] = FGWindItem(zero); //no Wind by default Wind[10000.0] = FGWindItem(zero); //no Wind by default Turbulence[-1000.0] = FGTurbulenceItem(zero); //no Turbulence by default Turbulence[10000.0] = FGTurbulenceItem(zero); //no Turbulence by default //Initialice with the CINA atmosphere Temperature[ 0.0] = +15.0 + 273.16; Temperature[11000.0] = -56.5 + 273.16; Temperature[20000.0] = -56.5 + 273.16; AirPressure = FGAirPressureItem(101325.0); VaporPressure[-1000.0] = FG_WEATHER_DEFAULT_VAPORPRESSURE; //in Pa (I *only* accept SI!) VaporPressure[10000.0] = FG_WEATHER_DEFAULT_VAPORPRESSURE; //in Pa (I *only* accept SI!) //Clouds.insert(FGCloudItem()) => none SnowRainIntensity = 0.0; snowRainType = Rain; LightningProbability = 0.0; } unsigned int FGPhysicalProperties::getNumberOfCloudLayers(void) const { return Clouds.size(); } FGCloudItem FGPhysicalProperties::getCloudLayer(unsigned int nr) const { map::const_iterator CloudsIt = Clouds.begin(); //set the iterator to the 'nr'th entry for (; nr > 0; nr--) CloudsIt++; return CloudsIt->second; } ostream& operator<< ( ostream& out, const FGPhysicalProperties2D& p ) { typedef map::const_iterator wind_iterator; typedef map::const_iterator turbulence_iterator; typedef map::const_iterator scalar_iterator; out << "Position: (" << p.p[0] << ", " << p.p[1] << ", " << p.p[2] << ")\n"; out << "Stored Wind: "; for (wind_iterator WindIt = p.Wind.begin(); WindIt != p.Wind.end(); WindIt++) out << "(" << WindIt->second.x() << ", " << WindIt->second.y() << ", " << WindIt->second.z() << ") m/s at (" << WindIt->first << ") m; "; out << "\n"; out << "Stored Turbulence: "; for (turbulence_iterator TurbulenceIt = p.Turbulence.begin(); TurbulenceIt != p.Turbulence.end(); TurbulenceIt++) out << "(" << TurbulenceIt->second.x() << ", " << TurbulenceIt->second.y() << ", " << TurbulenceIt->second.z() << ") m/s at (" << TurbulenceIt->first << ") m; "; out << "\n"; out << "Stored Temperature: "; for (scalar_iterator TemperatureIt = p.Temperature.begin(); TemperatureIt != p.Temperature.end(); TemperatureIt++) out << Kelvin2Celsius(TemperatureIt->second) << " degC at " << TemperatureIt->first << "m; "; out << "\n"; out << "Stored AirPressure: "; out << p.AirPressure.getValue()/100.0 << " hPa at " << 0.0 << "m; "; out << "\n"; out << "Stored VaporPressure: "; for (scalar_iterator VaporPressureIt = p.VaporPressure.begin(); VaporPressureIt != p.VaporPressure.end(); VaporPressureIt++) out << VaporPressureIt->second/100.0 << " hPa at " << VaporPressureIt->first << "m; "; out << "\n"; return out << "\n"; } inline double F(const WeatherPrecision factor, const WeatherPrecision a, const WeatherPrecision b, const WeatherPrecision r, const WeatherPrecision x) { const double c = 1.0 / (-b + a * r); return factor * c * ( 1.0 / (r + x) + a * c * log(abs((r + x) * (b + a * x))) ); } WeatherPrecision FGPhysicalProperties::AirPressureAt(const WeatherPrecision x) const { const double rho0 = (AirPressure.getValue()*FG_WEATHER_DEFAULT_AIRDENSITY*FG_WEATHER_DEFAULT_TEMPERATURE)/(TemperatureAt(0)*FG_WEATHER_DEFAULT_AIRPRESSURE); const double G = 6.673e-11; //Gravity; in m^3 kg^-1 s^-2 const double m = 5.977e24; //mass of the earth in kg const double r = 6368e3; //radius of the earth in metres const double factor = -(rho0 * TemperatureAt(0) * G * m) / AirPressure.getValue(); double a, b, FF = 0.0; //ok, integrate from 0 to a now. if (Temperature.size() < 2) { //take care of the case that there aren't enough points //actually this should be impossible... if (Temperature.size() == 0) { cerr << "ERROR in FGPhysicalProperties: Air pressure at " << x << " metres altiude requested,\n"; cerr << " but there isn't enough data stored! No temperature is aviable!\n"; return FG_WEATHER_DEFAULT_AIRPRESSURE; } //ok, I've got only one point. So I'm assuming that that temperature is //the same for all altitudes. a = 1; b = TemperatureAt(0); FF += F(factor, a, b, r, x ); FF -= F(factor, a, b, r, 0.0); } else { //I've got at least two entries now //integrate 'backwards' by integrating the strip ]n,x] first, then ]n-1,n] ... to [0,n-m] if (x>=0.0) { map::const_iterator temp2 = Temperature.upper_bound(x); map::const_iterator temp1 = temp2; temp1--; if (temp1->first == x) { //ignore that interval temp1--; temp2--; } bool first_pass = true; while(true) { if (temp2 == Temperature.end()) { //temp2 doesn't exist. So cheat by assuming that the slope is the //same as between the two earlier temperatures temp1--; temp2--; a = (temp2->second - temp1->second)/(temp2->first - temp1->first); b = temp1->second - a * temp1->first; temp1++; temp2++; } else { a = (temp2->second - temp1->second)/(temp2->first - temp1->first); b = temp1->second - a * temp1->first; } if (first_pass) { FF += F(factor, a, b, r, x); first_pass = false; } else { FF += F(factor, a, b, r, temp2->first); } if (temp1->first>0.0) { FF -= F(factor, a, b, r, temp1->first); temp1--; temp2--; } else { FF -= F(factor, a, b, r, 0.0); return AirPressure.getValue() * exp(FF); } } } else { //ok x is smaller than 0.0, so do everything in reverse map::const_iterator temp2 = Temperature.upper_bound(x); map::const_iterator temp1 = temp2; temp1--; bool first_pass = true; while(true) { if (temp2 == Temperature.begin()) { //temp1 doesn't exist. So cheat by assuming that the slope is the //same as between the two earlier temperatures temp1 = Temperature.begin(); temp2++; a = (temp2->second - temp1->second)/(temp2->first - temp1->first); b = temp1->second - a * temp1->first; temp2--; } else { a = (temp2->second - temp1->second)/(temp2->first - temp1->first); b = temp1->second - a * temp1->first; } if (first_pass) { FF += F(factor, a, b, r, x); first_pass = false; } else { FF += F(factor, a, b, r, temp2->first); } if (temp2->first<0.0) { FF -= F(factor, a, b, r, temp1->first); if (temp2 == Temperature.begin()) { temp1 = Temperature.begin(); temp2++; } else { temp1++; temp2++; } } else { FF -= F(factor, a, b, r, 0.0); return AirPressure.getValue() * exp(FF); } } } } return AirPressure.getValue() * exp(FF); }