Documentation

rrsigma

Compute relative density ratio

Syntax

s = rrsigma(rho, mach, g)

Description

s = rrsigma(rho, mach, g) computes m density relative ratios, s, from m static densities, rho, m Mach numbers, mach, and m specific heat ratios, g. rho must be in kilograms per meter cubed.

Examples

Determine the relative density ratio for three densities:

sigma = rrsigma([1.225 0.3639 0.0953], 0.5, 1.4)

sigma =

1.1297    0.3356    0.0879

Determine the relative density ratio for three densities and three different heat ratios:

sigma = rrsigma([1.225 0.3639 0.0953], 0.5, [1.4 1.35 1.4])

sigma =

1.1297    0.3357    0.0879

Determine the relative density ratio for three densities at three different conditions:

sigma = rrsigma([1.225 0.3639 0.0953], [0.5 1 2], [1.4 1.35 1.4])

sigma =

1.1297    0.4709    0.3382

Assumptions and Limitations

For cases in which total density ratio is desired (Mach number is nonzero), the total density is calculated assuming perfect gas (with constant molecular weight, constant pressure specific heat, and constant specific heat ratio) and dry air.

References

Aeronautical Vestpocket Handbook, United Technologies Pratt & Whitney, August, 1986 