Total air temperature is a term used generally in aviation. In other applications it is called stagnation temperature. Total air temperature is measured by a specially designed temperature probe mounted on the surface of the aircraft. The probe is designed to bring the air to rest relative to the aircraft. As the air is brought to rest kinetic energy is converted to internal energy. The air is compressed and experiences an adiabatic increase in temperature.

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  • Total air temperature is a term used generally in aviation. In other applications it is called stagnation temperature. Total air temperature is measured by a specially designed temperature probe mounted on the surface of the aircraft. The probe is designed to bring the air to rest relative to the aircraft. As the air is brought to rest kinetic energy is converted to internal energy. The air is compressed and experiences an adiabatic increase in temperature. Therefore total air temperature is higher than the static (or ambient) air temperature. Total air temperature is an essential input to an air data computer in order to enable computation of static air temperature and hence true airspeed. The relationship between static and total air temperatures is given by: \frac{T_\mathrm{total}}{T_{0}}={1+\frac{\gamma -1}{2}M_a^2} where: <math>T_{0}= static air temperature <math>T_\mathrm{total}= total air temperature (kelvin or degree Rankine) <math>M_{a}= Mach number <math>\gamma\ =\, ratio of specific heats = approx 1.4 for air In practice the total air temperature probe will not perfectly recover the energy of the airflow and the temperature rise may not be entirely due to adiabatic process. In this case an empirical recovery factor (less than 1) may be introduced to compensate: \frac{T_\mathrm{total}}{T_{0}}={1+\frac{\gamma -1}{2}eM_a^2} Where: e = recovery factor (also noted Ct) Typical recovery factors Platinum wire ratiometer thermometer ("flush bulb type"): e ≈ 0.75 - 0.9 Double platinum tube ratiometer thermometer ("TAT probe"): e ≈ 1 Other notations Total air temperature (TAT) is also called: indicated air temperature (IAT) or ram air temperature (RAT) Static air temperature (SAT) is also called: outside air temperature (OAT) or true air temperature The difference between TAT & SAT is called ram rise (RR) RR=TAT-SAT \, In practice the ram rise is negligible for aircraft flying at (true) airspeeds under Mach 0.2
  • 總溫（亦稱停滯溫度、滯溫、全溫）（對應英文的Total Temperature、Stagnation Temperature），是一個與空氣動力學相關的名詞。
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  • Total air temperature is a term used generally in aviation. In other applications it is called stagnation temperature. Total air temperature is measured by a specially designed temperature probe mounted on the surface of the aircraft. The probe is designed to bring the air to rest relative to the aircraft. As the air is brought to rest kinetic energy is converted to internal energy. The air is compressed and experiences an adiabatic increase in temperature.
  • 總溫（亦稱停滯溫度、滯溫、全溫）（對應英文的Total Temperature、Stagnation Temperature），是一個與空氣動力學相關的名詞。
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  • Total air temperature
  • 總溫
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