1.) A 40-ft wide rectangular channel carries 950 ft3/sec at a depth of 6 ft. If n = 0.025, what must the channel slope be in order to produce uniform flow at the 6-ft depth? Is this flow subcritical or supercritical? What is the critical slope that would cause the flow to just flip to the other flow profile (subcritical → supercritical or supercritical → subcritical)? 2.) Continuing with Problem 1:a. What is the alternate flow depth? (hint: in Problem 1 you should have found that flow was subcritical, so now you're finding the supercritical flow depth)b. What is the critical rise of the surface bed (Δzcrit) that would just cause the flow to flip to supercritical?c. What is the critical width (bcrit) of a throat in a contraction of the channel that would just cause the flow to switch to supercritical?

1.) A 40-ft wide rectangular channel carries 950 ft3/sec at a depth of 6 ft. If n = 0.025, what must the channel slope be in order to produce uniform flow at the 6-ft depth? Is this flow subcritical or supercritical? What is the critical slope that would cause the flow to just flip to the other flow profile (subcritical → supercritical or supercritical → subcritical)? 2.) Continuing with Problem 1:a. What is the alternate flow depth? (hint: in Problem 1 you should have found that flow was subcritical, so now you're finding the supercritical flow depth)b. What is the critical rise of the surface bed (Δzcrit) that would just cause the flow to flip to supercritical?c. What is the critical width (bcrit) of a throat in a contraction of the channel that would just cause the flow to switch to supercritical?

Traffic and Highway Engineering

5th Edition

ISBN:9781305156241

Author:Garber, Nicholas J.

Publisher:Garber, Nicholas J.

Chapter16: Highway Drainage

Section: Chapter Questions

Problem 13P

See similar textbooks

Similar questions

1.) A 40-ft wide rectangular channel carries 950 ft3/sec at a depth of 6 ft. If n = 0.025, what must the channel slope be in order to produce uniform flow at the 6-ft depth? Is this flow subcritical or supercritical? What is the critical slope that would cause the flow to just flip to the other flow profile (subcritical → supercritical or supercritical → subcritical)? 2.) Continuing with Problem 1:a. What is the alternate flow depth? (hint: in Problem 1 you should have found that flow was subcritical, so now you're finding the supercritical flow depth)b. What is the critical rise of the surface bed (Δzcrit) that would just cause the flow to flip to supercritical?c. What is the critical width (bcrit) of a throat in a contraction of the channel that would just cause the flow to switch to supercritical? Please answer the second problem
What will be the depth of flow in a trapezoidal concrete-lined channel that has a water discharge of 1000 cfs? The channel has a slope of 1 ft in 500 ft. The bottom width of the channel is 10 ft, and the side slopes are I vertical to 1 horizontal. m = 0.109
The bed width of a trapezoidal channel is 5.0 m, 5,= 0.0004, the side slope is m = 2 horizontal: 1 vertical, and the n value is 0.02: y = 3.0 m is the normal depth of flow. Calculate and plot the resulting gradually varied flow using the direct step method, when the channel flows into a pool at the downstream end and the pool elevation is 1.25 m higher than the channel bed elevation at the downstream end. Estimate the length of the gradually varied flow that the pool elevation produces.
A trapezoidal channel having a bottom slope of 0.001 is carrying a flow of 75 m3/s. The channel bottom is 50 m wide, n = 0.025, and the channel side slopes are 1 vertical to 1.5 horizontal. If a control structure is built at the downstream end that raises the water depth at the downstream end to 12 m, determine the amount by which the channel banks must be raised along its length. Assume the channel had uniform flow prior to the construction of the control structure.
A long length of lined trapezoidal channel has a base width 6.0 m and side slopes of 2 horizontal : 1 vertical. The bed slope is 0.001, Manning's n = 0.015 and the flow rate is 10 m³ / s find the normal depth, critical depth, the critical velocity, and the minimum specific energy of the flow.
An unsymmetrical trapezoidal channel of most efficient section with one side inclined from horizontal by 35 and the other inclined from vertical by 40 is to be designed to carry a 1.0 cubic meters per second discharge. Determine the flow stage type on the channel if roughness coefficient is 0.030 and average longitudinal slope is 0.175. Use Manning’s equation.
A trapezoidal channel having a bottom width of 6.1 m and side slopes of 1.5H : 1 V is carrying a flow of 126 m3/s at a flow depth of 5.79 m. The bottom slope is 0.00008, Manning n = 0.013 and the channel length is 5 km. There is constant-level reservoir at the upstream end of the channel. A sluice gate at the downstream end is suddenly closed at time t = 0 s. (a) Compute the transient conditions until t = 2000 s by using the method of characteristics. (b) Plot the computed flow depth in the channel at t = 0, 500, 1000, 1500 and 2000 s. (c) Plot the variation of the flow depth with time at 1.5, 2.5, 3.0 and 5.0 km from the reservoir. (d) By using different values of Δt/Δx, investigate the effect of interpolation error on the computed wave height and wave shape. (e) Show that the method of characteristic fails when a shock or bore is formed when the gate is closed in 10 s and the wave propagates in the channel.
A flow of 30 m3 /s occurs in a trapezoidal channel having a base width of 3 m, side slopes 1 vertical to 2 horizontal. Determine the critical depth, yc.
There is a rectangular channel that will be excavated downstream of a dam after a stilling basin both with a width of 15 meters. The depth of the wather flow upstream of the dam is 4.27 meters and the discharge flow above the dam is 112.5 cubic meters per second. the channel wil be excavated in earth and n = .o25 and maintains a uniform flow depth under a subcritical flow regime. I need to determine 1. the bottom channel slope needed in the downstream channel and 2. the length of the stilling basin if the dissipation stucture starts at dissipated along the structure. The design should consider that the flow depth at the end of the still basin is similar to the flow depth in the channel. For a more realistic approach in the design, the head loss between the station upstream of the dam and the station at the beginning of the still basin is 10% of the velocity head observed at the beginning of the basin
A right-angled triangular channel carries a flow of 16,000 l/s. The Manning’s n = 0.020 and the slope is 2 m/3000 m.(a) Determine the critical depth [m] for this flow.(b) Determine Froude number for the flow when the depth of flow is 0.6 m.(c) Determine the normal depth of flow [m]
An open channel is V-shaped, each side being inclined at 45 degrees to thevertical. If the flow rate is 3 m3/s when the depth of water at the centre is 0.52m, calculate the slope of the bed of the channel. Use Manning’s coefficient n =0.013.
For a rectangular channel 5 m wide carrying a flow of 15 m3/s, determine the critical depth and the critical velocity.