Chapter 18, Problem 5P

5. (20 Points) Consider a channel width change in the same 7-foot wide rectangular in Problem 4. The horizontal channel narrows as depicted below. The flow rate is 90 cfs, and the energy loss (headloss) through the transition is 0.05 feet. The water depth at the entrance to the transition is initially 4'. 1 b₁ TOTAL ENERGY LINE V² 129 У1 I b₂ TOP VIEW 2 PROFILE VIEW h₁ = 0.05 EGL Y₂ = ? a) b) c) 2 Determine the width, b₂ that will cause a choke at location 2. Determine the water depth at the downstream end of the channel transition (y₂) section if b₂ = 5 feet. Calculate the change in water level after the transition. Plot the specific energy diagram showing all key points. Provide printout in homework. d) What will occur if b₂ = = 1.5 ft.?

4. (20 Points) A transition section has been proposed to raise the bed level a height Dz in a 7-foot wide rectangular channel. The design flow rate in the channel is 90 cfs, and the energy loss (headloss) through the transition is 0.05 feet. The water depth at the entrance to the transition section is initially 4 feet. b₁ = b = b2 1 TOTAL ENERGY LINE V² 129 Ут TOP VIEW 2 hloss = 0.05 " EGL Y₂ = ? PROFILE VIEW a) Determine the minimum bed level rise, Dz, which will choke the flow. b) If the step height, Dz = 1 ft, determine the water depth (y2) at the downstream end of the channel transition section. Calculate the amount the water level drops or rises over the step. c) Plot the specific energy diagram showing all key points. Provide printout in Bework. d) What will occur if Dz = 3.0 ft.?. Crest Front View

1. (20 Points) Determine the critical depth in the trapezoidal drainage ditch shown below. The slope of the ditch is 0.0016, the side slopes are 1V:2.5H, the bottom width is b = 14', and the design discharge is 500 cfs. At this discharge the depth is y = 4.25'. Also, determine the flow regime and calculate the Froude number. Ye= ? Z b