In aircraft design, the density of an airframe structure can be estimated, its a specific formula as it depends on the materials used and the design of the structure. However, you can define it as follows:
- ρ = Density of the fluid (in kilograms per cubic meter, kg/m³)
- P = Pressure of the fluid (in pascals, Pa)
- R = Specific gas constant for the fluid (in J/(kg·K))
- T = Temperature of the fluid (in kelvin, K)