Quote:
Originally Posted by winkosmosis
According to the diagrams here, the pressure inside the tube is higher than static pressure Pitot Tubes
Look at the equations. They depend on stagnation pressure being higher than static, because you can't take the square root of a negative number
V = \sqrt{\frac{2 (p_t - p_s)}{\rho}}
Pitot tube - Wikipedia, the free encyclopedia
Since the tube is pointing into the airflow, it has to be higher pressure inside than outside. Stick your head out the car window and you can feel the pressure increase in your mouth. Ram air intakes on cars wouldn't work otherwise. |
The stagnation pressure *is* static pressure inside a closed duct with air flow going through it. It always takes more *pressure* either in the form of delta-P or differential to cause air to flow.
I shall mention again that the more accurate pitot tubes have *two* pressure taps.
1) One for static (pressure)
2) One for vacuum (velocity component)
The difference or delta-P between the two tells you exactly the air flow velocity of the air flowing past it.
Jim.