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| DOI：10.13522/j.cnki.ggps.20180083 |
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| Method to Calculate Economic Cross-section of Parabolic Composite Channel |
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LI Gang, HE Wuquan, ZHAI Donghan, PENG Chenglin, GUO Yinong
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1.College of Water Resources and Architectural Engineering, Northwest A &F University, Yangling 712100, China:2.The Ministry of Education Key Laboratory of Agricultural Water and Soil Engineering, Yangling 712100, China;3.Liaoning Northwest Water Supply Co., Ltd, Shenyang 110000, China
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| Abstract: |
| 【Objective】Cross section is a parameter in channel design and this paper presents a method to calculate economic cross section of composite channel with parabolic cross section and flatten bottom. 【Method】 From the optimal hydraulic cross section and using curve-fitting against experimental data, we obtained the optimal H/H0 ratio the parabolic water surface width to water depth be η=1.666. We then derived a formula to calculate the economic cross section of the composite channel. 【Result】 When flow rate in the channel was Q=26 m3/s and other parameters were n=0.015, i=0.000 52 and α=1.03, the water depth was H=2.054 m, the bottom width of the channel was b=4.447 m, the cross-section the water was A=13.818 m2 and the wet length was χ=10.037 m. Under the same flow rate, roughness and slope ratio, the parabolic-shape composite channel had the smallest economic cross section, reduced 1.65% compared to the trapezoid and 1.29% compared to the arc-shaped foot trapezoid. 【Conclusion】 Parabolic composite channel is most economical. |
| Key words: parabolic composite channel; practical economic section; calculation method |
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