The Aerospace Toolbox for Python contains a collection of functions intended for aerospace engineering applications. The toolbox is developed (and currently tested only) in a Python 2.7 environment and requires a recent version of NumPy and SciPy. The toolbox is designed to allow quick and robust evaluation of different functions and to properly accept and handle array-like data structures.
Features
- Functions for evaluation of the standard atmosphere and custom defined atmospheres. Isentropic relations, normal shock wave relations and Prandtl-Meyer expansion waves. And more!
- The theoretical formulas are evaluated by either direct substition or iteration with the Newton-Raphson method if the former is not possible.
- Each function has a full docstring explaining it's syntax and usage. Docstrings follow the NumPy docstring standard.
- All functions accept input data in any form that can be converted to an array. This includes scalars, lists, tuples, matrices and ndarrays. Each functions returns it's results in original form.
- Includes a module which wraps most of the functions in MATLAB Aerospace Toolbox syntax.
Installation
The easiest way to obtain the most recent version of the Aerospace Toolbox is by downloading the source as a ZIP-file. Extract the contents to a folder and install the package by running the following command:
python setup.py install
A Python 2.7 distribution with NumPy and SciPy is needed in order to make proper use of the Aerospace Toolbox. A recent version of matplotlib is required to run the example scripts.
Usage
If you want to use the Aerospace Toolbox in your scripts, you can write the following command to import all the functions:
from aerotbx import *
This will import the main functions and modules into your namespace. From here you can start using the functions provided by the toolbox. In the case you come from MATLAB and are used to the syntax from it's aerospace toolbox, you can use the matlab module that comes with this package. You can import all the MATLAB-style functions with the following:
from aerotbx.matlab import *
Examples
You can easily convert values from one unit to another by using the convert function. The function accepts an array_like data structure as input, followed by two strings representing the input unit and target unit.
>>> convert(30, 'cm', 'ft') #30 centimeters to feet
0.98425196850393692
>>> convert([0, 15, 30], 'C', 'K') #degrees celcius to kelvin
[273.15, 288.15, 303.15]
The function flownormalshock returns a tuple of flow values from normal shockwave theory. You can input one of the flow values as array_like data and the function will calculate the rest:
>>> flowvalues = flownormalshock(M=3) #upstream Mach number = 3
>>> flowvalues[1] #downstream Mach number
0.47519096331149141
>>> flowvalues = flownormalshock(Pitot=3) #Rayleight-Pitot
>>> flowvalues[0] #upstream Mach number
1.3858511209068562
The International Standard Atmosphere (ISA) can be evaluated with the stdatmos function. The following example uses matplotlib to plot the temperature gradient from 0 to 80 kilometers geometrical altitude.
>>> from pylab import *
>>> h_array = linspace(0, 80000)
>>> h, T, P, rho, a = stdatmos(h=h_array)
>>> plot(T, h)
>>> xlabel("Temperature [K]")
>>> ylabel("Height [M]")
>>> show()
Another way of using the stdatmos function is to find the altitude at which a certain temperature, pressure or density occurs. The pressure altitude of 26 kPa can be found as follows:
>>> stdatmos(P=26000)[0] #should be about 10km
10124.61855654098
For more information on all available functions and usages, refer to the source code on github. You can also use the python help function to display the docstring provided with each function:
>>> help(geoidheight)