Water ispumped through a 70m long 04m diameter pipe from a l

Water is.pumped through a 70-m long, 0.4-m diameter pipe from a lower reservoir to a higher reservoir whose surface is 12 m above the lower one. The sum of the minor loss cofficients for the system is K_L = 1.4. When the pump adds 40 kW to the water the flowrate is 0.2 m^3/s. Determine the pipe roughness.

Solution

as shown in the figure