Question: A common problem today is aging infrastructure. For example, in many parts of the United States wooden water mains still exist ( dating back to

A common problem today is aging infrastructure. For example, in many parts of the United States wooden water mains still exist (dating back to the 1800's). For this problem we will consider the benefits of replacing our aging water mains, solely from a frictional perspective. In this case we will consider replacing an old wooden water main with a more modern material (PVC). The old wooden main was 25 meters long with an equivalent sand roughness (kss) of 0.005 meters, and diameter of 450mm. The new pipe will be made of PVC with an equivalent sand roughness of 0.00045 meters. The new pipe will have the same length and diameter as the old pipe. For both pipes the change in head along the length of pipe will be maintained at 0.5 meters. Perform the following tasks assuming water temperature of 10C(kinematic viscosity, v=1.30610-6(:m2s}.
Hint: When in doubt about which power formula to use, always start by assuming flow in Manning's Range. Sometimes, based upon available information, you can use the ratio Rk and the power formula sheet to provide an initial estimate for the appropriate rough turbulent flow range (e.g. Lower Manning, Manning, or Upper
Manning)- this indicates which power formula is likely applicable. However, as a final check you should always confirm that the proper flow range and power formula were used.
a) What is the slope of the energy grade line (SEGL)?
b) Using the appropriate power formula, determine the discharge capacity (Q) of the new pipe.
c) Using R/ks, Re', and Rew along with the power formula sheet, confirm that the correct flow range was used to calculate Q for the new pipe.
d) What is the discharge capacity (Q) of the old pipe?
e) Calculate and compare friction factors for the old and new pipes. (For the online assessment, you will be asked to consider the relationship between friction factor, pipe roughness, and flow).
f) What are the characteristic PL values for both the old and new pipe?
A common problem today is aging infrastructure.

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