Consider air flow at a mean velocity of 5.0 m/s through a smooth pipe of diameter 0.10 m and length 10 m, at 27 °C. The air comes from a tank at atmospheric pressure.

(a) If there is a sudden contraction at the inlet, what is the length of the entrance region?

(b) How does the actual pressure drop (from just outside the inlet to the end of the pipe segment) compare with that for fully developed flow?

(c) Confirm that ρ is nearly constant.