Atmosphere.h

/*
    Written by Nikilesh Ramesh
*/
 
 
 
#include <iostream>
#include <cmath>
#include <map>
#include <vector>
#include "eigen.h"
 
// ----------- Constants ------- //
#define GAS_CONST 8.31446261815324 // Universal Gas Constant [J/(K*mol)] 
#define SPECIFIC_GAS_CONST 287.05287 // Gas Constant for air
#define GRAVITY_ACCEL 9.80665   // Gravitational acceleration [m/s^2]
#define SEALEVEL_PRESSURE 101325 // P0, sea level pressure [Pa]
#define SEALEVEL_TEMP 288.15 // sea level temperature [K]
#define AVAGADRO_CONST 6.02214076e23 // Avagadro's Constant
#define SEALEVEL_MOLARMASS  28.964420e-03 // (NOT PRIMARY, DERIVED) Molar mass of air at sea level [kg/mol]
#define SPECIFIC_GAS_CONST 287.05287 // specific gas constant (Assumed constant)
#define RADIUS_OF_EARTH 6356766     //See references for this number
 
// --- Other Definitions ---- // 
 
#define BASE_PRESSURE layer_const(0)
// to be completed, to tidy up the code....
 
 
 
class Atmosphere {
public:
    explicit Atmosphere(float pressure);
 
    float get_altitude();
 
    Eigen::Vector4f get_layer_constants(float p);
 
    float to_geopotential(float alt); // additional feture to be added, right now everything is in geometric
 
 
private:
 
    // Modifiable values
    int geometric_alt;
    int geopotential_alt;
    Eigen::Vector4f layer_const;
 
    float altitude(float pressure);
 
    // matrix of layer constants
    // each Layer  =  {Geopotential [m], Temperature [K], Temp Gradient[K/m]}
    Eigen::Matrix<float, 9, 4> layers;
 
 
};