Is there a significant difference between the discharge coefficient derived from the experiment with that of coefficient of discharge from Francis formula? Discuss the possible reason for such discrepancy

Here, 20 degree celcius water is being siphoned from a reservoir, see attached image. What would be the minimum flow rate be, without cavitation occuring in the system at points 2 and 3?

Two identical pumps are connected in series and deliver water through an 45cmdiameter, 2.2km long, commercial steel pipe from reservoir A (surface elevation = 50m) to reservoir B(surface elevation = 100m). Consider minor losses of a square-edged inlet, exit, and swing-type checkvalve. Determine the discharge, the total head added by the pumps, and the total power output. The pumpcharacteristics for a single pump is tabulated below. Assume that the kinematic viscosity is 1x10-6 m 2/s and a specific weight of 9.79kN/m 3 . Plot the system and pump characteristic curves on a single plot. Besure to label the axes appropriately (i.e., include units). Be sure to include a legend to demark the systemhead curve and the pump characteristic curve.

Due to corrosion and scaling, the roughness height of a pipe k increases with its years in service t, varying approximately as where k0 is the roughness of the new pipe. For a cast iron pipe, k0 ≈ 0.26 mm, and ε ≈ 0.00001 m per year. Estimate the discharge (volume flow rate) of water through a 20 cm diameter cast iron pipe 500 m long as a function of time over a 20-year period. Assume the pressure drop is constant and equal to 150 kP a. 1