In state and national forests it is common to store water in large water towers for reserve in the case of forest fires. To deliver water, the reservoir is connected to a downpipe and then a horizontal cast iron piping system. The downpipe is 80 inches high. The horizontal cast system is 600 inches in length. All the poping is 4 in in diameter. The loss co-efficient for the 90 degree flanged elbow is Kl = 0.3 and the aged cast-iron pipe has a characteristic roughness measured with a micrometer and is equal to 0.51mm.
Use the definition of the loss coefficent and the friction factor for flow in a straight pipe to convert the loss coefficient for the pipe fixture into an equivalent length Leq. Using the moody chart for this flanged elbow the equivalent length of the pipe is 10D. What assumptions have you made using this quantity?