Quote:
Originally Posted by winkosmosis
That's was my whole point. The inside of the tube that points into airflow is higher pressure than the surrounding air, not lower.
Pressure - Wikipedia, the free encyclopedia
Stagnation pressure is the pressure a fluid exerts when it is forced to stop moving. Consequently, although a fluid moving at higher speed will have a lower static pressure, it may have a higher stagnation pressure when forced to a standstill. Static pressure and stagnation pressure are related by the Mach number of the fluid. In addition, there can be differences in pressure due to differences in the elevation (height) of the fluid. See Bernoulli's equation (note: Bernoulli's equation only applies for incompressible, inviscid flow).
The pressure of a moving fluid can be measured using a Pitot tube, or one of its variations such as a Kiel probe or Cobra probe, connected to a manometer. Depending on where the inlet holes are located on the probe, it can measure static pressure or stagnation pressures. |
*Stagnation pressure is a consequence of the vehicle attacking a stationary air mass or vis-versa in a wind tunnel.
*The stagnation pressure contains the local atmospheric component and the 'ram' component.
*The 'static' portion from the probe,when subtracted from ( hooked to the other side of the manometer) leaves the 'velocity' pressure,the indication of airspeed.
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* Inviscid,incompressible flow is what we have outside the boundary layer of road vehicles.