FALL 2018
FIRST MIDTERM
MONDAY, OCTOBER 8, 2018, 1600-1650
Name: ___________________________ Red ID _______________________ Grade:__________
- (20%) A high overflow spillway has a downstream slope after the point of tangency
of 0.6 H to 1 V (see detail in right figure below). The Darcy-Weisbach friction factor of smooth concrete
is fD = 0.032.
What is the prevailing Froude number immediately downstream of the point of tangency?
- (20%)
On July 31, 1976, the Big Thompson Canyon, near Loveland, Colorado, experienced a record flood event.
Peak flood depths were estimated at 18 ft. The average width of the canyon is 64 ft.
Assume critical flow prevailed during the passage of the flood.
Based on this assumption, provide an estimate of the peak discharge.
- (20%) A hydraulically wide channel has a mean velocity u = 2 m/s , flow depth y = 2 m, and the wave flood celerity is c = 3 m/s. What are the Froude and Vedernikov numbers?
- (40%) Please answer the following questions in a brief statement.
- According to Prof. Ponce, what is the most important parameter in open-channel hydraulics?
- What four forces are used in open-channel flow analysis?
- What width/depth ratio will assure hydraulically wide conditions in an open channel?
- What do energy and momentum have in common?
- What is the neutral-stability Froude number in a wide rectangular channel with Chezy friction?
- For what flow condition (Froude number), under Chezy friction, do the Seddon and Lagrange waves have the same celerity and attenuation?
- What is the physical meaning of the critical slope in a hydraulically wide channel?
- What is the minimum value of Manning's n that can be encountered in practice?
- (20%) A hydraulically wide channel has a mean velocity u = 2 m/s , flow depth y = 2 m, and the wave flood celerity is c = 3 m/s. What are the Froude and Vedernikov numbers?