1. Air enters a circular duct with a Mach number of 3.0. The friction factor is 0.01.
(a) How long a duct (measured in diameters) is required to reduce the Mach numb to 2.0?
2. A 50 x 50 cm duct is 10 m in length. Nitrogen enters at M1 = 3.0 and leaves at M2 = 1.7, with T2 = 280 K and P2 = 7 x 104 N/m2.
(a) Find the static and stagnation conditions at the entrance.
(b) What is the friction factor of the duct?