Pitot Tube

V = \frac{2Δ p}{ρ} = 2 g h

Stagnation (total) pressure minus static pressure is the dynamic pressure ρV²/2. A pitot-static tube measures Δp; an open manometer reading h (same fluid) gives V=√(2gh) if the manometer fluid is the flowing fluid.

$V$ (m/s): Speed
$Δ p$: p0 − p
$h$ (m): Manometer dynamic head

Step-by-step solved example

Air-speed pitot: Δp=250 Pa, ρ=1.20 kg/m³. V?

Stagnation vs static pressure gives V = √(2Δp/ρ).

1. V
V=√(2×250/1.20)=√416.7=20.4 m/s.
$V = 20.4 m/s$

Answer: 20.4 m/s

10 practice questions

0/10 correct

1.Dynamic pressure is

2.Stagnation point has

3.If the manometer fluid is the flowing water, V=

4.Pitot measures

5.ρ=1000, Δp=5000 Pa. V=

6.A blocked pitot tube in aircraft is dangerous because

7.Static port should sense

8.Compressible high-Mach flow needs

9.Units: Δp in Pa, ρ in kg/m³ → V in

10.If V doubles, Δp