Nozzle Area Ratio Formula

Equation for calculate nozzle area ratio is,

[A / A×] = [1/m × (1+((k-1)/2)m²)/(1+((k-1)/2))]^{[k+2/(2(k-1))]}

where,
A - cross-sectional area of nozzle passage at a given downstream location in nozzle
A* - cross-sectional area of nozzle throat
M - Mach number of flow at a given downstream location in nozzle
A/A* - nozzle area ratio

Note: both Mach number and area ratio are dimensionless.