Question 6.25: A trapezoidal channel with a bottom width b = 12 ft, and a s...

Open Channel Flow: Numerical Methods and Computer Applications

A trapezoidal channel with a bottom width b = 12 ft, and a side slope m = 1.5 initially contains a uniform flow both upstream and downstream from a gate. (The bottom slopes of the channel are such that a uniform flow is possible both upstream and downstream from the gate for the flow rate that is occurring.) The uniform depth and the velocity upstream from the gate are: $Y_{o1}$ = 5 ft and $V_{o1}$ = 7 ft/s. The gate is first instantly closed so that it produces a depth of 2 ft immediately downstream from it. Thereafter, its position is adjusted slowly so that the rate of change inflow rate is decreased by dQ/dt = 0.2 cfs/s. Using 20 s time steps, solve the depths and velocities upstream and downstream from the gate over a 400 time period.

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