ambiance package

Submodules

ambiance.ambiance module

Compute atmospheric properties for heights ranging from -5 km to 80 km.

The implementation is based on the ICAO standard atmosphere from 1993.

References:

ICAO93(1,2): International Civil Aviation Organization ; Manual Of The ICAO Standard Atmosphere – 3rd Edition 1993 (Doc 7488) – extended to 80 kilometres (262 500 feet)
WISA19: Wikipedia ; International Standard Atmosphere ; https://en.wikipedia.org/wiki/International_Standard_Atmosphere Accessed: 2019-07-28

class ambiance.ambiance.Atmosphere(h, check_bounds=True)

Bases: object

Representation of the ICAO standard atmosphere (1993)

All input and output is using SI units
The main constructor takes the geometric (actual) height as input
Single values, vectors or matrices are accepted as input

Usage:

Compute a properties such as pressure for a given height:

>>> Atmosphere(0).pressure
array([101325.])

Values out of valid height range will not be computed:

>>> Atmosphere(-6e3)
Traceback (most recent call last):
    ...
ValueError: Value out of bounds. Lower limit: -5004 m. Upper limit: 81020 m.

Create an atmosphere object with given support points (heights in metre):

>>> atmos = Atmosphere([0, 1000, 5000, 17777, 35e3, 80e3])
>>>

Compute basic properties such as density, temperature or pressure:

>>> atmos.density
array([1.22500002e+00, 1.11165967e+00, 7.36428613e-01, 1.25975595e-01,
       8.46333291e-03, 1.84578859e-05])

>>> atmos.temperature
array([288.15      , 281.65102237, 255.67554322, 216.65      ,
       236.51337209, 198.63857625])

>>> atmos.pressure
array([1.01325000e+05, 8.98762776e+04, 5.40482622e+04, 7.83442282e+03,
       5.74591263e+02, 1.05246447e+00])

property H: Geopotential heights \(H\)

static T2t(T)

Convert from temperature \(T\) in Kelvin to \(t\) in degree Celsius

\(t = T - T_i\)

property collision_frequency: Collision frequency \(\omega\)

property density: Air density \(\rho\)

property dynamic_viscosity: Dynamic viscosity \(\mu\)

classmethod from_density(rho): Return a new instance for given density value(s)

classmethod from_pressure(p): Return a new instance for given pressure value(s)

static geom2geop_height(h)

Convert geometric height \(h\) to geopotential height \(H\)

\(H = \frac{r h}{r + h}\)

static geop2geom_height(H)

Convert geopotential height \(H\) to geometric height \(h\)

\(h = \frac{r H}{r - H}\)

property grav_accel: Gravitational acceleration \(g\)

property h: Geometric heights \(h\)

property kinematic_viscosity: Kinematic viscosity \(\nu\)

property layer_name: Get layer names as strings

property layer_nums: Array of same shape as ‘self.H’ with layer numbers (int)

property mean_free_path: Mean free path \(l\)

property mean_particle_speed: Mean particle speed \(\bar{\nu}\)

property number_density: Number density \(n\)

property pressure: Air pressure \(p\)

property pressure_scale_height: Pressure scale height \(H_p\)

property specific_weight: Specific weight \(\gamma\)

property speed_of_sound: Speed of sound \(a\)

static t2T(t)

Convert from temperature \(t\) in degree Celsius to \(T\) in Kelvin

\(T = t + T_i\)

property temperature: Air temperature \(T\) in Kelvin

property temperature_in_celsius: Air temperature \(t\) in Celsius

property thermal_conductivity: Thermal conductivity \(\lambda\)

class ambiance.ambiance.CONST

Bases: object

Constants defined in the ICAO standard atmosphere (1993)

Notes:

All values are given in SI-units.

Attributes:

g_0: Standard gravitational acceleration [m/s^2]
M_0: Sea level molar mass [kg/mol]
N_A: Avogadro constant [1/mol]
P_0: Sea level atmospheric pressure [Pa]
R_star: Universal gas constant [J/(K*mol)]
R: Specific gas constant [J/(K*kg)]
S: Sutherland’s empirical constant in the equation for dynamic viscosity [K]
T_i: Temperature of the ice point at mean sea level [K]
T_0: Sea level temperature [K]
t_i: Celsius temperature of the ice point at mean sea level [degC]
t_0: Celsius sea level temperature [degC]
beta_s: Sutherland’s empirical constant in the equation for dynamic viscosity [kg/(m*s*K**(1/2))]
kappa: Adiabatic index [-]
rho_0: Sea level atmospheric density [kg/m^3]
sigma: Effective collision diameter of an air molecule [m]
r: Nominal Earth’s radius [m]
h_min: Lower boundary of acceptable geometric heights [m]
h_max: Upper boundary of acceptable geometric heights [m]
H_min: Lower boundary of acceptable geopotential heights [m]
H_max: Upper boundary of acceptable geopotential heights [m]
p_min: Lower boundary of acceptable pressures [Pa]
p_max: Upper boundary of acceptable pressures [Pa]
rho_min: Lower boundary of acceptable densities [kg/m^3]
rho_max: Upper boundary of acceptable densities [kg/m^3]
LAYER_SPEC_PROP: Table containing layer specific properties
LAYER_DICTS: Dictionary containing layer specific properties

Notes on ‘LAYER_SPEC_PROP’:

Table with columns
1. H_b
  
  geopotential base height [m]
2. T_b
  
  base temperature [K]
3. beta
  
  base temperature gradient [kg/(m*s*K^(1/2))]
4. p
  
  base pressure [Pa]
5. layer name
  
  string representation of layer name
Values for (1,2,3) from table D in [ICAO93]
Values for (4) for pressure from [ICAO93]
Values for (5) from [WISA19]

H_base = 71000.0

H_max = 80000

H_min = -5000

H_top = 80000.0

LAYER_DICTS = {1: {'H_base': -5000.0, 'H_top': 0.0, 'T': 320.65, 'beta': -0.0065, 'name': 'troposphere', 'p': 177687.0}, 2: {'H_base': 0.0, 'H_top': 11000.0, 'T': 288.15, 'beta': -0.0065, 'name': 'troposphere', 'p': 101325.0}, 3: {'H_base': 11000.0, 'H_top': 20000.0, 'T': 216.65, 'beta': 0.0, 'name': 'tropopause', 'p': 22632.0}, 4: {'H_base': 20000.0, 'H_top': 32000.0, 'T': 216.65, 'beta': 0.001, 'name': 'stratosphere', 'p': 5474.87}, 5: {'H_base': 32000.0, 'H_top': 47000.0, 'T': 228.65, 'beta': 0.0028, 'name': 'stratosphere', 'p': 868.014}, 6: {'H_base': 47000.0, 'H_top': 51000.0, 'T': 270.65, 'beta': 0.0, 'name': 'stratopause', 'p': 110.906}, 7: {'H_base': 51000.0, 'H_top': 71000.0, 'T': 270.65, 'beta': -0.0028, 'name': 'mesosphere', 'p': 66.9384}, 8: {'H_base': 71000.0, 'H_top': 80000.0, 'T': 214.65, 'beta': -0.002, 'name': 'mesosphere', 'p': 3.95639}}

LAYER_NUM_FIRST = 1

LAYER_NUM_LAST = 8

LAYER_SPEC_PROP = [[-5000.0, 320.65, -0.0065, 177687.0, 'troposphere'], [0.0, 288.15, -0.0065, 101325.0, 'troposphere'], [11000.0, 216.65, 0.0, 22632.0, 'tropopause'], [20000.0, 216.65, 0.001, 5474.87, 'stratosphere'], [32000.0, 228.65, 0.0028, 868.014, 'stratosphere'], [47000.0, 270.65, 0.0, 110.906, 'stratopause'], [51000.0, 270.65, -0.0028, 66.9384, 'mesosphere'], [71000.0, 214.65, -0.002, 3.95639, 'mesosphere'], [80000.0, 196.65, -0.002, 0.886272, 'mesosphere']]

MAX_STR_LEN_LAYER_NAME = 12

M_0 = 0.02896442

N_A = 6.02257e+23

P_0 = 101325.0

R = 287.05287

R_star = 8.31432

S = 110.4

T = 214.65

T_0 = 288.15

T_i = 273.15

beta = -0.002

beta_s = 1.458e-06

g_0 = 9.80665

h_max = 81020

h_min = -5004

i = 8

kappa = 1.4

layer_name = 'mesosphere'

layer_pair = ([71000.0, 214.65, -0.002, 3.95639, 'mesosphere'], [80000.0, 196.65, -0.002, 0.886272, 'mesosphere'])

p = 3.95639

p_max = 177837.4089432764

p_min = 0.886216717024069

r = 6356766

rho_0 = 1.225

rho_max = 1.9317906916235779

rho_min = 1.569949463833277e-05

sigma = 3.65e-10

t_0 = 15.0

t_i = 0.0

ambiance.ambiance.pairwise(iterable)

Iterate pairwise

s -> (s0,s1), (s1,s2), (s2, s3), …

See: https://docs.python.org/3/library/itertools.html

ambiance package

Submodules

ambiance.ambiance module

References:

Module contents