Standard Atmosphere Functions

Standard atmosphere gas properties. Support for n-dim inputs, non-standard atmospheres, units, etc.

Standard atmosphere functions based on the 1976 Standard Atmosphere. Returns density, speed of sound, temperature, pressure, and viscosity for a given altitude input up to 86 km.

Functions are designed to be useful for those designing and analyzing aircraft and have the following features:

•Inputs may be scalar, vector, matrix, or n-dimensional arrays. Functions are vectorized and fast for computing conditions at a large number of points simultaneously. Especially for n-dimensional problems, it is faster than the built-in atmosisa that comes with the aerospace toolbox.

•Temperature offset option for non-standard atmospheres, e.g analyzing hot day aircraft performance.

•Absolute temperature option for non-standard atmospheres, e.g for when OAT is known.

•Either SI or imperial units (and easy to set your preferred default).

•Units consistency can be enforced by using the Physical Units Toolbox, reducing errors and making code clearer.

•Returns everything needed to easily determine important parameters such as dynamic pressure, Mach number, Reynolds number, stagnation temperature, etc.

•Option for geometric instead of geopotential altitude input.

•Density altitude function allows reverse lookup of altitude based on gas properties.

•Stripped-down, troposphere-only function included for when computation speed is a priority.

References: ESDU 77022; www.pdas.com/atmos.html