CE 40450 Hydraulics, Spring 2015, Homework 5 Due Date

CE 40450 Hydraulics, Spring 2015, Homework 5
Due Date: February 26, beginning of class
TA: Samaresh Midya.
TA Office Hours: Monday 3-4PM, Tuesday 3:30-4:30PM, Fitzpatrick A59
Professor Office Hours/Tutorial: 5-6:30PM Tuesday, DB 311
(1) For the simple pipe network shown below, pipe 1 has a length of 4,000ft and is 1.5ft in
diameter. Pipe 2 has a length of 3,000ft and is 2ft in diameter. Determine the flow rate in
each pipe (ft3/s) and the head loss (ft) from A to B if all pipes are concrete with roughness of
0.003ft. Use initial flow rates of 25ft3/s for both pipes. Perform 2 Hardy-Cross iterations
only.
(2) Use the Hardy-Cross method and show all steps in iterations. Also, you may need to
change the friction factor slightly between iterations. Be sure that you use the initial flow
estimates as your starting points. 2 Iterations is OK.
A water distribution system is shown below. The demands are at nodes D (0.550m3/s) and E
(0.450m3/s). Water enters the system at node A from a reservoir with surface elevation
355.0m. All pipes are concrete with lengths and diameters provided in the table below.
Calculate the flow rate in each pipe given initial estimates below. Also, determine whether
the pressure at each node exceeds 185kPa, which is required by the customers.
Pipe
AB
AC
BD
CE
CB
ED
Flow (m3/s)
0.500
0.500
0.530
0.470
0.030
0.020
Length (m)
400
400
400
400
400
400
Diameter(m)
0.45
0.45
0.40
0.40
0.20
0.30
e/D
0.00080
0.00080
0.00090
0.00090
0.00080
0.00180
Node
A
B
C
D
E
Elev (m)
355
315.5
313.8
313.3
314.1
After installing the EPANET 2 program and the user’s manual on your computer (available for
the Windows platform, see class website for link) or using the programs installed in StinsonRemick. It is on most computers, but make sure to check.
(3) Reproduce results from the tutorial that is supplied with the program (note that in order to
launch the tutorial, you might need to upgrade Windows help system if you use your own
computer). Follow the instructions provided in the tutorial up to (and including) the section
'Running a single period analysis'. After running the single period analysis make tables listing:
(a) flow volume in each pipe segment, and (b) pressure at each node. These can be printed out
from the EPANET produced tables using the print command. (c) Export the network to a text file
using the ‘export’ command. Make sure that it did not output a binary file. Supply the tables and
the exported network in printed format.
(4) Create a new EPANET 2 project, now setting the default headloss formula to Darcy-Weisbach (D-W) and the default pipe roughness to 0.15 ×10-3 ft (this will be entered as 0.15 with
the link properties tables). By choosing standard pipe diameters (Nominal Inside Diameter, in
inches) from the attached chart, design a pipe network with specifications displayed in figure 1
and table 1. Design your network so that all the nodal pressures are greater than 20 psi. For
economic reasons, the pipe diameters should be the smallest possible to achieve the given
pressures. This means that there should be no pipe diameters that could be made smaller and still
give the required nodal pressures. Not all pipes should be the same diameter – you can have
different pipe diameters. Usually the pipes with the largest flows have the largest diameters.
Export (a) a picture of your network as in Figure 1, (b) the network properties using the export
command, (c) flows in all pipes, and (d) nodal pressures for the same conditions. It will be
easiest to make these tables by hand, copying the properties from the screen.
Figure 1. Pipe network for question 3. Make sure that you use the same numbering system (put
pipes and nodes in the same order).
Table 2. Standard pipe sizes. Use Nominal Inside Diameter for inputting pipe properties.
(5) A coastline has a depth that varies with distance from the shore y = Kx1/2 , where K = 1m1/2
and x is in m. If a tsunami is generated 40,000m offshore at 12:00PM, at what time will it reach
the shoreline?