1 open channel problems 2
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This document contains 10 examples of hydraulic engineering problems involving water flow through channels, over bumps and weirs, and hydraulic jumps. The examples involve calculating flow rates, velocities, depths, slopes, and other parameters using equations of open channel flow and hydraulic jumps. Diagrams are provided for some of the channel and jump configurations.
1 open channel problems 2
- 1. EXAMPLE #02 (10.2) Water at 20°C flows in a 30 cm wide rectangular channel at a depth of 10 cm and a flowrate of 80,000 cm3 /s. Estimate (a) the Froude number and (b) the Reynolds number. EXAMPLE #03 (10.8) An earthquake near the Kenai peninsula, Alaska, creates a single “tidal” wave called tsunami that propagates southward across the Pacific Ocean. If the average ocean depth is 4 km and seawater density is 1025 kg/m3 , estimate the time of arrival of this tsunami in Hilo, Hawaii. EXAMPLE #04 (10.11) A rectangular channel is 2 m wide and contains water 3 m deep. If the slope is 0.85° and the lining is corrugated metal, estimate the discharge for uniform flow.
- 2. EXAMPLE #05 (10.17-10.18-10.19) The trapezoidal channel as shown below is made of brickwork and slopes at 1:500. 1. Determine the flowrate if the normal depth is 80 cm. 2. Determine the normal depth for which the flowrate will be 8 m3 /s. 3. Let the surface be clean earth, which erodes if V exceeds 1.5 m/s. What is the maximum depth to avoid erosion?
- 3. EXAMPLE #06 (10.84) Consider the flow under the sluice gate. If y1=10 ft and all losses are neglected except the dissipation in the jump, calculate y2 and y3 and the percentage of dissipation, and sketch the flow to scale with the EGL included. The channel is horizontal and wide.
- 4. EXAMPLE #07 (10.89) Water 30cm deep is in uniform flow down a 1° unfinished concrete slope when a hydraulic jump occurs. If the channel is very wide, estimate the water depth y2 downstream of the jump.
- 5. EXAMPLE #08 (10.93) Water in horizontal channel accelerates smoothly over a bump and then undergoes a hydraulic jump. If y1 = 1m and y3 = 40cm, estimate (a) V1, (b) V3, (c) y4 and (d) the bump height, h.
- 6. EXAMPLE #09 (10.95) A 10 cm high bump in a wide horizontal water channel creates a hydraulic jump just upstream. Neglecting losses except in the jump, for case y3 = 30cm, estimate (a) V4, (b) y4, (c) V1 and (d) y1.
- 7. EXAMPLE #10 (C10.6) Figure shows a horizontal flow of water through a sluice gate, a hydraulic jump, and over 6 ft sharp crested weir. Channel, gate, jump and weir are all 8 ft wide unfinished concrete. Determine (a) the flow rate, (b) the normal depth, (c) y2, (d) y3 and (e) y4.