FALL 2013
FIRST MIDTERM
MONDAY, SEPTEMBER 30, 2013, 1600-1650
Name: __________________ Red ID ____________________ Grade:____ _________
- (25%) A high overflow spillway has a downstream slope after the point of tangency
of 0.6 H to 1 V (see figure below). The Darcy-Weisbach friction factor of smooth concrete
is fD = 0.03.
What is the prevailing Froude number right after the point of tangency?
- (25%)
On July 31, 1976, the Big Thompson Canyon, near Loveland, Colorado, experienced a record flood event.
The peak velocity was estimated by USGS at 27 fps. The width of the canyon near its mouth is 53 ft.
Assume critical flow prevailed during the passage of the flood.
Provide an estimate of the peak discharge.
- (25%) The overflow spillway at Turner reservoir, in San Diego County, is 8 ft wide. On February 24, 2005, after several days of heavy rain, the head over the spillway was 3 in. The discharge coefficient at the weir has been calibrated to be C = 2.98. What is the discharge?
- (25%) Please answer the following questions in a brief statement.
- Why is unsteady uniform flow not possible in practice?
- What four forces are used in open-channel flow analysis?
- What width/depth ratio will assure hydraulically wide conditions in an open channel?
- What is the neutral-stability Froude number in a wide rectangular channel with Chezy friction? With Manning friction?
- What is the minimum and maximum value of Manning's n encountered in practice? Where do they apply?
- (25%) The overflow spillway at Turner reservoir, in San Diego County, is 8 ft wide. On February 24, 2005, after several days of heavy rain, the head over the spillway was 3 in. The discharge coefficient at the weir has been calibrated to be C = 2.98. What is the discharge?