CIVE 612 OPEN-CHANNEL FLOW
SPRING 2008
ASSIGNMENT 3
Read Chapters 4 and 5 in Jain (2001).
Work problems 3.12, 3.14, 3.15, 3.17, 3.18, 3.19, 3.21, and 3.25 in Jain (2001). Also, work both problems
below. Turn in problem 1 for grading on 6 March 2008.
1. An 8-m wide rectangular channel has a flow depth of 4 m and a cross-section averaged velocity of 3.75
m/s. The channel bottom elevation is at 100 m above m.s.l. Assuming negligible head loss, design a
transition to produce a water level elevation downstream of the transition at 103.55 m above m.s.l. for
each of the following separate conditions: (a) the channel width remains constant; and (b) the channel
bed elevation downstream of the transition is at 100.21 m above m.s.l.
2. Find the upstream flow depth in a subcritical transition from an upstream rectangular flume that is 49 ft
wide to a downstream trapezoidal channel with a bottom width of 75 ft and side slopes of 2:1. The
bottom elevation drops 1 ft from the upstream flume to the downstream trapezoidal channel. The
steady flow rate is 12,500 ft3/s and the flow depth in the downstream trapezoidal channel is 22 ft. The
head loss through the transition is approximated by g
u
g
u
22
5.0 2
2
2
1−.
