اثر تراکم سازه‌های حاشیه پیچان‌رودها روی مشخصات جریان در مواقع سیلابی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه آب و سازه‌های هیدرولیکی، دانشکده فنی و مهندسی، دانشگاه ارومیه، ارومیه، ایران.

2 گروه هیدرولیک و مکانیک مهندسی رودخانه، دانشکده فنی و مهندسی، دانشگاه ارومیه، ارومیه، ایران.

3 مهندسی آب، دانشکده کشاورزی، دانشگاه زنجان، زنجان، ایران.

10.22059/jwim.2023.364637.1101

چکیده

رودخانه‌ها به‌عنوان زه‌کش طبیعی یک حوضه آبریز در تخلیه رواناب حاصل از بارش، به‌ویژه در مواقع سیلابی همواره موردتوجه بوده است. با توجه به شکل­گیری اکثر شهرها و روستاها در حاشیه رودخانه­ها و احداث سازه­هایی در سیلاب‌دشت آن‌ها یا گاهی تعرض به سیلاب‌دشتدشت‌ها، در مواقع سیلابی الگوی جریان رودخانه­ها همواره دچار تغییراتی می­شود، لذا مطالعه اندرکنش جریان­های سیلابی در کانال‌های مرکب پیچان در این مناطق، ضروری به‌نظر می­رسد. در این پژوهش با استفاده از نرم‌افزارFlow3D  که یک نرم‌افزار قوی در زمینه دینامیک سیالات محاسباتی است، به بررسی ساختار جریان و تنش برشی بستر در کانال مرکب پیچان تحت تأثیر تراکم سازه­ای سیلاب‌دشت در مواقع سیلابی پرداخته شده است. برای این منظور از شش نوع تراکم سازه‌ای صفر، هشت، 11، 16، 25 و 44 درصد روی سیلاب‌دشت با استفاده از بلوک­های غیرمستغرق و با فاصله‌های هفت، 14، 21، 28 و 35 سانتی­متر استفاده شده است. نتایج حاصل از شبیه­سازی عددی نشان داد که با افزایش تراکم سازه­ای روی سیلاب‌دشت از صفر به 44 درصد، مقدار سرعت متوسط مقطع کانال اصلی به‌طور میانگین 51 درصد، حداکثر ارتفاع سطح آزاد آب 25 درصد و میزان دبی متوسط عبوری از مقطع کانال اصلی 84 درصد افزایش می­یابد. هم‌چنین با افزایش مقدار تراکم سازه­ای روی سیلاب‌دشت، میزان تنش برشی بستر افزایش یافته، به­طوری­که مقدار حداکثر تنش برشی بستر از 32/1 به 61/4 پاسکال (حدود 250 درصد) افزایش نموده و به سمت مرکز کانال اصلی حرکت می­کند.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

The effect of structures density in the banks of meandering rivers on the flow characteristics during floods

نویسندگان [English]

  • Mohammad Naghavi 1
  • Mirali Mohammadi 2
  • Ghorban Mahtabi 3
1 Department of Civil Engineering, Faculty of Engineering, Urmia University, Urmia, Iran.
2 Department of Civil Engineering, Faculty of Engineering, Urmia University, Urmia, Iran.
3 Department of Water Engineering, Faculty of Agriculture, University of Zanjan, Zanjan, Iran.
چکیده [English]

Rivers as a natural drainage of a watershed have always been of interest in draining the runoff resulting from precipitation, especially during floods. Due to the formation of most cities and villages on the banks of rivers and the construction of structures in their floodplains, during floods, the pattern of river flow always undergoes changes, so it is necessary to study the interaction of flood flows of meandering compound channel in these areas. In this research, by using Flow3D software, which is a powerful software in the field of computational fluid dynamics, the flow structure and bed shear stress in meandering compound channel under the effect of structural density of floodplain during floods have been investigated. For this purpose, six types of structural density of 0, 8, 16, 11, 25 and 44% have been used on the floodplain using non-submerged blocks with distances of 7, 14, 21, 28 and 35 cm. The results of the numerical simulation showed that with the increase of structural density in the floodplain from zero to 44%, the average velocity of the main channel, the maximum water surface elevation and the amount of flow passing through the main channel increased by 51%, 25% and 84% respectively. Also, with the increase in structural density on the floodplain, the amount of bed shear stress has increased so that the maximum bed shear stress has increased from 1.32 to 4.61 pascal (250 percent) and moves towards the center of the main channel.

کلیدواژه‌ها [English]

  • Compound channel
  • Meandering
  • Structural density
  • Flow structure

مراجع

  1. Ayaseh, A., Salmasi, F., Hossienzade Dalir, A., & Arvanaghi, H. (2019). A performance comparison of CCHE2D model with empirical methods to study sediment and erosion in gravel-bed rivers. International Journal of Environmental Science and Technology, 16, 7933-7942.
  2. Da Silveira e Lorena, M. L. (1992). Meandering compound flow. Ph.D. Thesis, University of Glasgow, UK.
  3. De Marchis, M., & Napoli, E. (2008). The effect of geometrical parameters on the discharge capacity of meandering compound channels. Advances in Water Resources, 31(12), 1662-1673.
  4. Kiely, G. (1990). Overbank flow in meandering channels the important mechanisms. International Conference on River Flood Hydraulics, 17-20 September, Wallingford, England, 207-217.
  5. Knight, D. W., & Demetriou, J. D. (1983). Flood plain and main channel flow interaction. Journal of Hydraulic Engineering, 109(8), 1073-1092.
  6. Liu, C., Shan, Y., Liu, X., & Yang, K. (2016). Method for assessing stage-discharge in meandering compound channels. ICE-Water Manage, 169(1), 17-29.
  7. Liu, C., Shan, Y., Liu, X., Yang, K., & Liu, H. (2016). The effect of floodplain grass on the flow characteristics of meandering compound channels. Journal of Hydrology, 542, 1-17.
  8. Liu, C., Wright, N., Liu, X., & Yang, K. (2014). An analytical model for lateral depth-averaged velocity distributions along a meander in curved compound channels. Advances in Water Resources, 74, 26-43.
  9. Mushatet, K. S. (2011). Simulation of turbulent flow and heat transfer over a backward-facing step with ribs turbulators. Thermal Sci, 15(1), 245-255.
  10. Naghavi, M., Mohammadi, M. A., & Mahtabi, G. (2019). Flow Velocity in Meandering Compound Channel under the Influence of Sinusoidal Change. Modares Civil Engineering journal, 19(5), 208-219. (In Persian).
  11. Naghavi, M., Mohammadi, M., & Mahtabi, G. (2020). Turbulence Intensity and Boundary Shear Stress in Meandering Compound Channel under the Influence of Sinusoidal Changes. Journal of Modeling in Engineering, 18(60), 53-69. (In Persian).
  12. Naghavi, M., Mohammadi, M., & Mahtabi, G. (2021). Numerical simulation of flow velocity distribution and shear stress in meandering compound channels. Iranian Water Researches Journal, 15(1), 23-34. (In Persian).
  13. Naghavi, M., Mohammadi, M., & Mahtabi, G. (2021). Transverse Flow Characteristics in the Meandering Compound Channels. Amirkabir Journal of Civil Engineering, 53(8), 3499-3516. (In Persian).
  14. Naghavi, M., Mohammadi, M., & Mahtabi, G. (2021). On the effect of relative flood depth on flow hydraulics in meandering compound channels. Irrigation and Water Engineering, 11(3), 55-78. (In Persian).
  15. Naghavi, M., Mohammadi, M., & Mahtabi, G. (2022). An experimental evaluation of the blocks in floodplain on hydraulic characteristics of flow in a meandering compound channel. Journal of Hydrology, 612, 127976.
  16. Naghavi, M., Mohammadi, M., & Mahtabi, G. (2023). The effect of building arrangement on the flow characteristics in meandering compound channels. Journal of Environmental Management, 331, 117288.
  17. Naghavi, M., Mohammadi, M., Mahtabi, G., & Abraham, J. (2023). Experimental assessment of velocity and bed shear stress in the main channel of a meandering compound channel with one-sided blocks in floodplain. Journal of Hydrology, 617, 129073.
  18. Nikubakht, E., Hamidifar, H., & Keshavarzi, A. (2017). Effect of Floodplain Non-Submerged Vegetation on Bed Variation in Meandering Compound Rivers. Iranian Journal of Eco Hydrology, 5(2), 461-470. (In Persian)
  19. Salmasi, F., Ayaseh, A., Dalir, A. H., & Arvanaghi, H. (2020). Flow pattern study in Beshar River and its two straight and meander reaches using CCHE2D model. Applied Water Science, 10(1), 1-15.
  20. Sellin, R. H. J., & Willetts, B. B. (1996). Three-Dimensional Structures, Memory and Energy Dissipation in Meandering Compound Channel Flow, Floodplain Processes. Chichester, England, John Wiley & Sons.
  21. Shan, , Liu, X., Yang, K., & Liu, C. (2017). Analytical model for stage-discharge estimation in meandering compound channels with submerged flexible vegetation. Advances in Water Resources, 108, 170-183.
  22. Shan, Y., Huang, S., Liu, C., Guo, Y., & Yang, K. (2018). Prediction of the depth-averaged two-dimensional flow direction along a meander in compound channels. Journal of Hydrology, 565, 318-330.
  23. Spooner, J., & Shiono, K. (2003). Compound Meandering Channels with overbank flow. Water and Maritime Engineering, 156(3), 225-233.
  24. Toebes, G. H., & Sooky, A. A. (1967). Hydraulics of meandering rivers with flood plains. S. C. E. J. of Waterways and Harbors, 33, 213-236.
  25. Yang, K., Cao, S., & Knight, D. W. (2007). Flow patterns in compound channels with vegetated floodplains. Journal of Hydraulic Eng, 133(2), 148-159.
مدیریت آب و آبیاری
دوره 14، شماره 1
فروردین 1403
صفحه 123-139

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