خصوصیات جریان‌های عرضی در کانال‌های مرکب پیچان

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی دکترای مهندسی عمران- آب و سازه های هیدرولیکی، دانشکده فنی و مهندسی، دانشگاه ارومیه، ارومیه، ایران

2 دانشیار مهندسی عمران- هیدرولیک و مکانیک مهندسی رودخانه، دانشکده فنی و مهندسی، دانشگاه ارومیه، ارومیه، ایران

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

چکیده

مسیل‌های طبیعی در طول مسیر خود همواره مئاندرهایی تشیکل می‌دهند و در نظر گرفتن اثر این پیچ و خم‌ها در مسیر جریان بر الگوی خصوصیات جریان حائز اهمیت است. در هنگام بروز سیلاب، سطح آب از مقطع اصلی رودخانه فراتر رفته و وارد دشت­های سیلابی آن می‏شود. در این حالت مقطع رودخانه به صورت مقطع مرکب در می‌آید. در این تحقیق با استفاده از نرم­افزارFlow3D  که یک نرم‌افزار قوی در زمینه دینامیک سیالات محاسباتی است، به بررسی قدرت جریان عرضی و چرخش گردابه‌ها در کانال مرکب پیچان تحت اثر تغییر عمق نسبی و میزان سینوسیتی پرداخته شده است. برای این منظور از شش کانال با مقدار سینوسیتی مختلف و سه عمق نسبی متفاوت استفاده شده است. نتایج حاصل از شبیه­سازی عددی نشان می‌دهد مقدار بیشینه قدرت چرخشی گردابه‌ها با افزایش میزان سینوسیتی از 1 به 1/209، به طور متوسط در حدود 195درصد افزایش می‌یابد و مقدار بیشینه قدرت جریان عرضی و چرخش گردابه‌ها، در کانال با زاویه 45 درجه‌ای قوس مرکزی و میزان سینوسیتی 1/209 رخ می‌دهد. همچنین در مقطع اصلی کانال مرکب پیچان، برای تمام مقادیر سینوسیتی، با کاهش مقدار عمق نسبی، بر میزان قدرت جریان عرضی و چرخش گردابه‌ها افزوده شده و میزان تغییر قدرت جریان عرضی نسبت به تغییر عمق نسبی با افزایش میزان سینوسیتی کاسته می‌شود.  

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Transverse Flow Characteristics in the Meandering Compound Channels

نویسندگان [English]

  • Mohammad Naghavi 1
  • Mirali Mohammadi 2
  • Ghorban Mahtabi 3
1 Ph.D. Candidate in Civil Eng. Water & Hydraulic Structures, Department of Civil Engineering, Faculty of Eng., Urmia University.
2 Associate Prof. in Civil Eng. Hydraulics & River Mechanics, Dept. of Civil Eng., Faculty of Eng., Urmia University, Urmia, Iran
3 Assistant Professor in Water Engineering, Department of Water Engineering, Faculty of Agriculture, University of Zanjan.
چکیده [English]

Natural channels always form meanders along their path, and it is important to consider the effect of this meander on the flow characteristics pattern. When a flood occurs, the water level crosses the main section of the river and enters its floodplains. In this case, the river crossing becomes a compound cross-section. In this study, using the Flow3D software (powerful software in the field of computational fluid dynamics),  the vortex rotational power and transverse flow in the meandering compound channel under the influence of relative depth and Sinusoidal Change were investigated. For this purpose, six channels with different sinuosity and three relative depths were used. The results of the numerical simulation showed that the maximum rotational power of vortices increased with an average of about 195% by increasing the sinusoidal rate from 1 to 1.209. The maximum rotational strength of the vortices and the transverse flow rate occurred at a 45-degree angle to the central arc and a sinusoidal value of 1.209. In the main cross-section of the meandering compound channel, for all sinusoidal values, by decreasing the relative depth, the vortex and transverse rotation strengths increased and the rate of change in transverse current power relative to relative depth changes decreased with increasing sinusoidal rate.

کلیدواژه‌ها [English]

  • Meandering Compound Channel
  • sinusoidal
  • relative depth
  • transverse flow
  • Vortex
[1] M.R. Kornise, Meander Travel in Alluvial Streams, Proceedings of the International Workshop on Alluvial River Problems, Sarita Prakashan Meerut, New Delhi, India, 1980.
[2] M.H. Rezaei Moghadam, K.A. Khoshdel, Research on Sinuosity of Ahar Chay Meanders in Ozomdel Plain, Varzeghan, East Azerbaijan, Iran. Journal of Geography and Environmental Planning, 20 (1) (2009) 101–112. (In Persian)
[3] M.H. Rezaei Moghadam, M.R. Sarvati, S. Asghari Sareskanrood, Investigation of geometric alterations of Gezel Ozan River considering Geomorphologic and Geologic parameters, Journal of Geography and Environmental Planning, 23 (2) (2012) 1–14. (In Persian)
[4] M.H. Rezaei Moghadam, M.R. Nikjoo, H. Maleki, An Investigation of Morphological Changes of Azadroud River Pattern using Geometric Indices, Journal of Geography and Environmental Planning, 28(4)(2018) 1–16. (In Persian)
[5] G.H. Toebes, A.A. Sooky, Hydraulics of meandering rivers with flood plains, A. S. C. E. J. of Waterways and Harbors, 33(1967) 213–236.
[6] D.W.  Knight, J.D, Demetriou, Flood plain and main channel flow interaction. Journal of Hydraulic Engineering, 109 (8) (1983) 1073–1092.
[7] G. Kiely, Overbank flow in meandering channels the important mechanisms, International Conference on River Flood Hydraulics, (1990) 207–217.
[8] M.L. Da Silveira e Lorena, Meandering compound flow, Ph.D. Thesis, University of Glasgow. UK, 1992.
[9] D.A. Ervine, B.B. Willetts, R.H.J. Sellin, M. Lorena,  Factors Affecting Conveyance in Meandering Compound Flows, Journal of Hydraulic Engineering, 119 (12) (1993) 1383-1399.
[10] R.H.J. Sellin, B.B. Willetts, Three-Dimensional Structures, Memory and Energy Dissipation in Meandering Compound Channel Flow, Floodplain Processes, Edited by Anderson, M. G. Walling, D. E. and Bates, P. D. Chichester, England, John Wiley & Sons, 1996.
[11] K. Shiono, Y. Muto, Complex flow mechanisms in compound meandering channels with overbank flow, Journal of Fluid Mechanics, 376 (1998) 221–261.
[12] J. Spooner, k. Shiono, Compound Meandering Channels with overbank flow, Water and Maritime Engineering, 156(3)(2003) 225-233.
[13] M. de Marchis, E. Napoli, The effect of geometrical parameters on the discharge capacity of meandering compound channels, Advances in Water Resources, 31(2008) 1662–1673.
[14] P. Rameshwaran, X. Sun, K. Shiono, J.H. Chandler, R.H.J. Sellin, The modelling of compound channel flow: Physical Model of River Black water, Wallingford. UK, 2008.
[15] D.R. Shukla, K. Shiono, CFD modelling of meandering channel during floods, Proc. Inst. Civ. Eng.-Water Manag, 161(2008)1–12.
[16] K. Shiono, T.L. Chan, J. Spooner, P. Rameshwaran, J.H. Chandler, The effect of floodplain roughness on flow structures, bedforms and sediment transport rates in meandering channels with overbank flows: Part I, Journal of Hydraulic Research, 47(1) (2009) 5–19.
[17] C. Liu, N. Wright, X. Liu, K. Yang, An analytical model for lateral depth-averaged velocity distributions along a meander in curved compound channels, Advances in Water Resources, 74 (2014) 26–43.
[18] C. Liu, Y. Shan, X. Liu, K. Yang, Method for assessing stage-discharge in meandering compound channels, ICE-Water Manage, 169(1) (2016) 17–29.
[19] C. Liu, Y. Shan, X. Liu, K. Yang, H. Liu, The effect of floodplain grass on the flow characteristics of meandering compound channels, Journal of Hydrology, 542(2016) 1-17.
[20] Y. Shan, S. Huang, C. Liu, Y. Guo, K. Yang, Prediction of the depth-averaged two-dimensional flow direction along a meander in compound channels, Journal of Hydrology, 565(2018) 318–330.
[21] I.J. Moncho-Esteve, G. Palau-Salvador, M. García-Villalba, Y. Muto, K. Shiono, A Numerical Study of the Complex Flow Structure in a Compound Meandering Channel, Advances in Water Resources, 116 (2018) 95–116.
[22] M. Fazli, M.A. Kaviani, Investigation of Changing the Width of Flood Plains and Discharges on Secondary Flow in Prismatic Compound Channel, Journal of Civil and Environmental Engineering, 45(2) (2015) 47-58. (In Persian)
[23] S. Saeed-Golanik, M. Mohammadi, Numerical Consideration of Hydraulic Aspects of Flow in Meandering Prismatic Compound Channels by Flow3D Model, Proceedings. 5th International Congress on: Civil Eng, Architecture and Urban Development, 26-28 December 2017, Shahid Beheshti University, Tehran, Iran. (In Persian)
[24] S.H. Najafian, H. Younesi, A. Parsaei, H. Torabi-Poudeh, Physical and Numerical Modeling of Flow in Heterogeneous Roughness Non-Prismatic Compound Open Channel, Irrigation and Drainage Structures Engineering Research, 17(66) (2016)87-104. (In Persian)
[25] S.H. Najafian, H. Younesi, A. Parsaei, H. Torabi-Poudeh, Physical and Numerical Modeling of Flow Properties in Prismatic Compound Open Channel with Heterogeneous Roughness, Irrigation and Drainage Structures Engineering Research, 18(68) (2017)1-16. (In Persian)
[26] E. Nikubakht, H. Hamidifar, A. Keshavarzi, Effect of Floodplain Non-Submerged Vegetation on Bed Variation in Meandering Compound Rivers, Iranian Journal of Eco Hydrology, 5(2)(2017) 461-470. (In Persian)
[27] M. Naghavi, M. Mohammadi, GH. Mahtabi, Flow Velocity in Meandering Compound Channel under the Influence of Sinusoidal Change, Modares Civil Engineering journal, 19(5)(2019) 207-219. (In Persian)
[28] A. Parsaie, S. Dehdar-Behbahani, A.H. Haghiabi, Numerical modeling of cavitation on spillway’s flip bucket, Frontiers of Structural and Civil Engineering, 10 (2016)438-444.
[29] A. Parsaie, A. Moradinejad, A.H. Haghiabi, Numerical Modeling of Flow Pattern in Spillway Approach Channel, Jordan Journal of Civil Engineering, 12(1)(2018)1-9.
[30] A. Shukry, Flow around Bends in an Open Flume, American Society of Civil Engineers (ASCE), 115(1950)751-779.