py_atmosphere.mach_number

Functions

mach_number(altitude, alt_units, speed)

Calculate the Mach number of an object moving at a given altitude.

Module Contents

py_atmosphere.mach_number.mach_number(altitude, alt_units, speed)

Calculate the Mach number of an object moving at a given altitude.

Given an altitude, and assumptions of air composition, this function calculates the speed of sound in m/s in specific altitude using the formula: speed of sound = c = sqrt(gamma * R * T), where gamma and R are standard air properties, and T is the temperature at the given altitude. Then it calculates the Mach number of an object moving in said environment. The ratio of specific heats, gamma is 1.4. The gas constant R is 287.1 J/kg/K. Celsius to Kevin: Celsius + 273.15.

Parameters:

altitudefloat

A numeric value that represents the altitude of interest. This value is the reference to extract air properties, specifically, temperature, pressure and density.

alt_unitsstr

Units of the altitude input to function. Valid units are: m (meters), km (kilometers), ft (feet), miles (miles).

speed: float

Speed of the object in m/s.

Returns:

float

The Mach number (adimensional) in specific altitude, calculated as: speed / speed of sound as calculated in speed_of_sound function.

Examples

>>> mach_number(0.0, "ft", 340.4)
1.0