CIVL133 - WATER RESOU RCES ENGINEER ING SPRING 2009
PIPE NETWORKS
HOMEWORK 2
DUE: JANUARY 30, 2009
1. Calculate the flowrate in each pipe and pressure at each junction in the network shown. Assume cast
iron pipes are used and that the flow is fully rough. Neglect local losses and losses in the short piece
of pipe between the reservoir and point A. Water surface elevation in the reservoir is at 100m; the
network is horizontal and at an elevation of 10m. Use n = 2.
Do this problem by spreadsheet. Also: show hand calculations for your first Q adjustment (i.e.,
iterations 1 and 2, with iteration 1 being the initial guess for flowrates and iteration 2 being the first
adjustment). The solution should be accurate to Q/Qin = 1%.. Verify the answer using WaterCAD.
Submit a printout of the junction report with your spreadsheet.
Pipe Length
(m)
Diameter
(m)
AB 100 0.3
BD 50 0.3
AC 50 0.3
CD 100 0.2
CE 50 0.1
DE 112 0.2
Ans:
Junction Pressure (kPa)
A 882.9
B 641.3
C 855.4
D 601.7
E 539.0
2. Do Problem 6.127 in the Fluids text. You can choose how to complete this problem, but WaterCAD
may require the least amount of effort!
Ans:
Junction Pressure (psi)
A 120 (given)
B 108
C 103
D 75
0.4 m3/s
AB
0.4 m3/s
0.1 m3/s
E
C D