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| DOI：10.13522/j.cnki.ggps.2017.0229 |
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| Numerical Simulation of Distribution of Sediment Deposition on the Joints in Canal Systems |
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WANG Yanzhao, ZHANG Yaozhe
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College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling 712100, China
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| Abstract: |
| 【Objective】 Understanding how suspended sediments deposit in a canal system is critical to ensure canal service and in this paper, we numerically simulated sediment deposition at joints and diversion in a canal system. 【Method】 We developed a flow model for the rectangular outlet region in a lateral channel and solved water flow through it using the software FLUENT. The sediment transport and deposition, as well as the change in channel bed due to sediment deposition were solved by decoupling the fluid model and the sediment transport model; the associated equations were solved numerically using MATLAB. 【Result】 The results showed that, when upstream conditions remained the same, the maximum dredging cycle is 7.5 years if we took 90% of the design flowing capacity of the canal as minimum capacity that the channel should have after flow-capacity reduction due to sediment deposition. Sediment deposition created a sand barrier at the diversion area, impacting the flow rate ratio between the mainstream and its tributary. This consequently reduced the flow rate to 65.6% of its design value, and the width of the water flow cross-section at the canal bed was reduced to 37.5% of the width of the branch canal. 【Conclusion】 Sediment deposition at irrigation channel joints and diversion has considerable impact on flowing capacity of the main channel and its branches, and the proposed model help improve their management. |
| Key words: irrigation system; node; suspended load; sedimentation distribution; flow capacity |
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