Regarding Standard atmospheric conditions

[Deepesh]

Why do we take ISA conditions(Atm. Temperature, Atm. Pressure) as static and not stagnation?

Thanks

 

[jackwhirl]

Stagnation pressure is a static pressure. What is the context of your question that you perceive a difference?

 

[NatSusan]

for bringing up this interesting topic! The reason we typically use ISA conditions (Atmospheric Temperature and Pressure) as static instead of stagnation is because it is a more practical and realistic representation of the conditions in the atmosphere. Stagnation conditions would assume that the air is completely still, which is rarely the case in the real world.

Additionally, using stagnation conditions would require us to take into account factors such as velocity and dynamic pressure, which can vary greatly and make calculations more complicated. By using static conditions, we can simplify the calculations and still get a good understanding of the atmospheric conditions.

That being said, there are certain situations where using stagnation conditions may be more appropriate, such as in high-speed aerodynamics or when dealing with compressible flow. In those cases, it is important to carefully consider the conditions and choose the most appropriate reference frame for calculations.

Overall, using ISA conditions as static is a practical and widely accepted approach in many fields, but it is important to understand the limitations and when other conditions may be more suitable.