Chapter 15, Problem 68P

Figure 15.28 shows a simplified diagram of a Pitot tube, used for measuring aircraft speeds. The tube is mounted on the aircraft with opening A at right angles to the flow and opening B pointing into the flow. The gauge prevents airflow through the tube. Use Bernoulli’s equation to show that the plane’s speed relative to the air is $v=\sqrt{2\Delta p/\rho }$, where Δp is the pressure difference between the tubes and ρ is the density of air. (Hint: The flow must be stopped at B, but continues past A with its normal speed.)

FIGURE 15.28 Problem 66