Author: Christian Mayer
Date started: 28.05.99
- ---------- Copyright (C) 1999 Christian Mayer (vader@t-online.de) ----------
+ -------- 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
08.06.1999 Christian Mayer Changed sat_vp
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
+17.01.2000 Christian Mayer Added conversion routines make it easier for
+ JSBsim to use the weather database.
+18.05.2000 Christian Mayer Added function for geting the density when
+ temperature and pressure are given
*****************************************************************************/
/****************************************************************************/
/* dp: dew point in °C */
/* wb: approximate wetbulp in °C */
/* */
-/* NOTE: Pascal is the SI unit for preasure and is defined as Pa = N/m^2 */
+/* NOTE: Pascal is the SI unit for pressure and is defined as Pa = N/m^2 */
/* 1 mbar = 1 hPa = 100 Pa */
/* NOTE: °C isn't a SI unit, so I should use °K instead. But as all */
/* formulas are given in °C and the weather database only uses */
#define SAT_VP_CONST2 7.444072452
#define SAT_VP_CONST3 235.3120919
-inline WeatherPrecition sat_vp(const WeatherPrecition& temp)
+inline WeatherPrecision sat_vp(const WeatherPrecision temp)
{
//old:
//return 6.112 * pow( 10, (7.5*dp)/(237.7+dp) ); //in mbar
return SAT_VP_CONST1 * pow( 10, (SAT_VP_CONST2*temp)/(SAT_VP_CONST3+temp) ); //in pascal
}
-inline WeatherPrecition rel_hum(const WeatherPrecition& act_vp, const WeatherPrecition& sat_vp)
+inline WeatherPrecision rel_hum(const WeatherPrecision act_vp, const WeatherPrecision sat_vp)
{
return (act_vp / sat_vp) * 100; //in %
}
-inline WeatherPrecition dp(const WeatherPrecition& sat_vp)
+inline WeatherPrecision dp(const WeatherPrecision sat_vp)
{
return (SAT_VP_CONST3*log10(sat_vp/SAT_VP_CONST1))/(SAT_VP_CONST2-log10(sat_vp/SAT_VP_CONST1)); //in °C
}
-inline WeatherPrecition wb(const WeatherPrecition& t, const WeatherPrecition& p, const WeatherPrecition& dp)
+inline WeatherPrecision wb(const WeatherPrecision t, const WeatherPrecision p, const WeatherPrecision dp)
{
- WeatherPrecition e = sat_vp(dp);
- WeatherPrecition tcur, tcvp, peq, diff;
- WeatherPrecition tmin, tmax;
+ WeatherPrecision e = sat_vp(dp);
+ WeatherPrecision tcur, tcvp, peq, diff;
+ WeatherPrecision tmin, tmax;
if (t > dp)
{
}
-inline WeatherPrecition Celsius(const WeatherPrecition& celsius)
+// Assume that we've got an ideal gas in normal altitudes
+inline WeatherPrecision Density(const WeatherPrecision AirPressure, const WeatherPrecision Temperature )
{
- return celsius + 273.16; //Kelvin
+ const float rho0 = 1.293; /*density for air in normal altitudes at 0°C and 1013 mbar*/
+
+ return rho0 * 273.15 * AirPressure / (101300.0 * Temperature);
+}
+
+inline WeatherPrecision Celsius (const WeatherPrecision celsius)
+{
+ return celsius + 273.15; //Kelvin
}
-inline WeatherPrecition Fahrenheit(const WeatherPrecition& fahrenheit)
+inline WeatherPrecision Fahrenheit (const WeatherPrecision fahrenheit)
{
- return (fahrenheit * 9.0 / 5.0) + 32.0 + 273.16; //Kelvin
+ return (fahrenheit * 9.0 / 5.0) + 32.0 + 273.15; //Kelvin
}
-inline WeatherPrecition Kelvin2Celsius(const WeatherPrecition& kelvin)
+inline WeatherPrecision Kelvin2Celsius (const WeatherPrecision kelvin)
{
- return kelvin - 273.16; //Celsius
+ return kelvin - 273.15; //Celsius
}
-inline WeatherPrecition Kelvin2Fahrenheit(const WeatherPrecition& kelvin)
+inline WeatherPrecision Kelvin2Fahrenheit (const WeatherPrecision kelvin)
{
- return ((kelvin - 273.16) * 9.0 / 5.0) + 32.0; //Fahrenheit
+ return ((kelvin - 273.15) * 9.0 / 5.0) + 32.0; //Fahrenheit
}
-inline WeatherPrecition Celsius2Fahrenheit(const WeatherPrecition& celsius)
+inline WeatherPrecision Celsius2Fahrenheit (const WeatherPrecision celsius)
{
- return (celsius * 9.0 / 5.0) + 32.0; //Fahrenheit
+ return (celsius * 9.0 / 5.0) + 32.0; //Fahrenheit
}
-inline WeatherPrecition Fahrenheit2Celsius(const WeatherPrecition& fahrenheit)
+inline WeatherPrecision Fahrenheit2Celsius (const WeatherPrecision fahrenheit)
{
return (fahrenheit - 32.0) * 5.0 / 9.0; //Celsius
}
-inline WeatherPrecition Torr2Pascal(const WeatherPrecition& torr)
+inline WeatherPrecision Torr2Pascal (const WeatherPrecision torr)
+{
+ return (101325.0/760.0)*torr; //Pascal
+}
+
+inline WeatherPrecision Rankine2Kelvin (const WeatherPrecision Rankine)
+{
+ return (5.0 / 9.0) * Rankine; //Kelvin
+}
+
+inline WeatherPrecision JSBsim2SIdensity (const WeatherPrecision JSBsim)
+{
+ return JSBsim / 0.0019403203; //kg / cubic metres
+}
+
+inline WeatherPrecision psf2Pascal (const WeatherPrecision psf)
+{
+ return psf / 0.020885434; //lbs / square foot (used in JSBsim)
+}
+
+inline WeatherPrecision Kelvin2Rankine (const WeatherPrecision kelvin)
+{
+ return (9.0 / 5.0) * kelvin; //Rankine (used in JSBsim)
+}
+
+inline WeatherPrecision SIdensity2JSBsim (const WeatherPrecision SIdensity)
+{
+ return 0.0019403203 * SIdensity; //slug / cubic feet (used in JSBsim)
+}
+
+inline WeatherPrecision Pascal2psf (const WeatherPrecision Pascal)
{
- return (101325.0/760.0)*torr;
+ return 0.020885434 * Pascal; //lbs / square feet (used in JSBsim)
}
/****************************************************************************/
/****************************************************************************/
/****************************************************************************/
-#endif /*FGWeatherUtils_H*/
\ No newline at end of file
+#endif /*FGWeatherUtils_H*/
projects / flightgear.git / blobdiff