The density (ρ) of air in a scramjet engine can be calculated using the ideal gas law. The ideal gas law relates the density, pressure, temperature, and gas constant (R). The formula is as follows:
- ρ is the density of the air in kilograms per cubic meter (kg/m³).
- P is the pressure of the air in pascals (Pa).
- R is the specific gas constant of air in joules per kilogram per kelvin (J/(kg·K)).
- T is the absolute temperature of the air in kelvin (K).