Difference between a subsonic Pitot tube and supersonic one

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Discussion Overview

The discussion focuses on the differences between subsonic and supersonic Pitot tubes, particularly in relation to their measurement capabilities and the effects of shock waves in supersonic flows. The scope includes theoretical and mathematical considerations relevant to fluid dynamics.

Discussion Character

  • Technical explanation, Debate/contested

Main Points Raised

  • One participant requests clarification on the differences between subsonic and supersonic Pitot tubes.
  • Another participant suggests that the mathematical aspects are significant, referencing a Wikipedia article on Machmeters.
  • A later reply questions the accuracy of measurements taken by Pitot tubes in supersonic regimes, noting that the flow is non-isentropic and that stagnation pressure differs, potentially leading to inaccurate readings.
  • One participant expresses uncertainty about whether the Pitot tube itself is fundamentally different in supersonic conditions or if the Machmeter simply adjusts for these issues mathematically.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus, as there are competing views regarding the functionality and accuracy of Pitot tubes in supersonic flows versus subsonic flows.

Contextual Notes

The discussion highlights potential limitations in understanding the effects of shock waves and non-isentropic flow on Pitot tube measurements, as well as the reliance on mathematical corrections in supersonic conditions.

stephane
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Hi,

Please could you explain the difference between a subsonic Pitot tube and supersonic one

Thanks
 
Last edited by a moderator:
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rcgldr said:
Looks like significant part of this is the math involved. Wiki article:

http://en.wikipedia.org/wiki/Machmeter
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...?..
 
I'm not sure if the pitot tube is significantly different, or if a machmeter just compensates for supersonic issues with math.
 

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