Thanks for your response but I ask about thé shock ahead pitot in supersonic an since thé flow is non isentropic so thé stagnation pressure is différente so thé value measured by pitot is false in supersonic régime no...?..rcgldr said:Looks like significant part of this is the math involved. Wiki article:
http://en.wikipedia.org/wiki/Machmeter
A Pitot tube is a type of flow measurement device used to determine the velocity of a fluid, such as air or water, in a pipe or duct. It works by measuring the difference in pressure between the total pressure and static pressure of the fluid.
The main difference between a subsonic and supersonic Pitot tube is the range of velocities they can accurately measure. A subsonic Pitot tube is designed to measure velocities below the speed of sound, while a supersonic Pitot tube is designed to measure velocities above the speed of sound.
A subsonic Pitot tube has two openings: a forward-facing opening that collects the total pressure of the fluid, and a side-facing opening that collects the static pressure. The difference in pressure between these two openings is used to calculate the velocity of the fluid.
A supersonic Pitot tube has a single opening that collects both the total and static pressure of the fluid simultaneously. This allows for accurate measurement of supersonic velocities, as the pressure difference is not affected by shock waves.
The type of Pitot tube you should use depends on the velocity range of your experiment. If you are measuring velocities below the speed of sound, a subsonic Pitot tube is appropriate. If you are measuring velocities above the speed of sound, a supersonic Pitot tube is necessary for accurate results.