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Ebook 2,500 solved problems in fluid mechanics and hydraulics: Part 2

(BQ) Work the problems yourself, then check the answers, or go directly to the answers you need using the complete index. Compatible with any classroom text, Schaum’s 2500 Solved Problems in Fluid Mechanics and Hydraulics is so complete it’s the perfect tool for graduate or professional exam review. | CHAPTER 14 n Flow in Open Channels u 14.1 Water flows in a rectangular concrete open channel that is 12.0 m wide at a depth of 2.5 m. The channel slope is 0.0028. Find the water velocity and the flow rate. I V 1.0 n JR2 3 2 0.013 from Table A-13 R A p 12.0 2.5 2.5 12.0 2.5 1.765 m V 1.0 0.013 1.765 2 3 0.0028 5.945 m s Q Av 12.0 2.5 5.945 178 m3 s 14.2 Water flows in the symmetrical trapezoidal channel lined with asphalt shown in Fig. 14-1. The channel bottom drops 0.1 ft vertically for every 100 ft of length. What are the water velocity and flow rate f V 1.486 7 2 3 s1 2 0.015 from Table A-13 R A p A 16.0 4.5 2 4.5 3 4.5 2 132.8 ft2 p 16.0 2V 4.5 2 3 4.5 2 44.46 ft R 132.8 44.46 2.987 ft s 0.1 100 0.00100 V 1.486 0.015 2.987 2 0.00100 1 2 6.498 ft s Q Av 132.8 6.498 863 ft3 s 14.3 Water is to flow at a rate of 30 m3 s in the concrete channel shown in Fig. 14-2. Find the required vertical drop of the channel bottom per kilometer of length. f A 3.6 2.0 4.0 - 2.0 1.6 3.6 2 12.40 m2 V 1.0 n 2 3 s1 2 Q A 30 12.40 2.419 m s Ph 3.6 2.0 V 4.0 - 2.0 2 3.6 - 1.6 2 1.6 10.03 m R A pw 12.40 10.03 1.236 m 2.419 1.0 0.013 1.236 2 3 s 1 2 5 0.000746 This slope represents a drop of the channel bottom of 0.000746 m per meter of length or 0.746 m per kilometer of length. 356 FLOW IN OPEN CHANNELS Ũ 357 14.4 Water flows in the triangular steel channel shown in Fig. 14-3 at a velocity of 2.9 ft s. Find the depth of flow if the channel slope is 0.0015. f V 1.486 n K2 3 s1 2 R A pw 2 d d tan 27.5 2 2d cos 27.5 0.2309J 2.9 1.486 0.014 0.2309d 2 3 0.0015 1 2 d 2.57 ft Fig. 14-3 14J After a flood had passed an observation station on a river an engineer visited the site and by locating flood marks performing appropriate surveying and doing necessary computations determined that the cross-sectional area wetted perimeter and water-surface slope at the time of the peak flooding were 2960 m2 341 m and 0.00076 respectively. The engineer also noted that the channel bottom was earth with grass .