Q1. A certain part of cast iron piping of a water distribution system involves a parallel section. Both parallel pipes have a diameter of 30 cm, and the flow is fully turbulent. One of the branches (pipe A) is 1000 m long while the other branch (pipe B) is 3000 m long. If the flow rate through pipe A is 0.4 m³/s,

(i) Determine the flow rate through pipe B. Discard minor losses and assume the water temperature to be 15⁰C.

(ii) Show that the flow is fully rough and thus the friction factor is independent of Reynolds number.

Q2. The water at 20⁰C in a 10-m-diameter, 2-m-high aboveground swimming pool is to be emptied by unplugging a 5-cm-diameter,  25-m-long horizontal plastic pipe attached to the bottom of the pool. Determine the initial rate of discharge of water through the pipe  and the time (hours) it would take to empty the swimming pool completely assuming the entrance of the pipe is well-rounded with negligible loss. Take the friction factor of the pipe to be 0.022. Using the initial discharge velocity, check if this is a reasonable value for the friction factor.

Q3 A pump is to be selected for a waterfall in a garden. The water collects in a pond at the bottom, and the elevation difference between the free surface of the pond and the location where the water is discharged is 3 m. The flow rate of water is to be at least 8 L/s.

(i) Select an appropriate motor-pump unit for this job and

(ii) Identify three manufacturers with product model numbers and prices.

(iii) Make a selection and explain why you selected that particular product.

Q4 Write a two page report on the flaps used at the landing and trailing edges of the wings of large commercial aircraft. Discuss how the flaps affect the drag and lift coefficients during takeoff and landing.

Q5 Large commercial airplanes cruise at high altitudes (up to about 40,000 ft) to save fuel. Discuss how flying at high altitudes reduces drag and saves fuel. Also discuss why small planes fly at relatively low altitudes. (Two pages maximum with diagram)