شبیه‌سازی عددی استهلاک انرژی در مواجهه با انقباض هلالی‌شکل مسیر جریان

نوع مقاله : مقاله پژوهشی

نویسندگان

1 استاد، گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه مراغه

2 گروه عمران، دانشکده فنی و مهندسی، دانشگاه مراغه، مراغه، ایران

3 دانشجوی کارشناسی ارشد گروه عمران آب و سازه های هیدرولیکی، دانشکده فنی و مهندسی، دانشگاه مراغه، مراغه، ایران

چکیده

از روش­های کنترل و کاهش انرژی جریان، استفاده از سازه­های مستهلک­کننده انرژی و تشکیل پرش هیدرولیکی است. یکی از انواع این سازه­ها، المان­های تنگ­شدگی در مسیر جریان است که منجر به افت انرژی جریان عبوری می­شود. در تحقیق حاضر به بررسی عددی تأثیر تنگ­شدگی هلالی­شکل به­عنوان سازه مستهلک‌کننده انرژی در مسیر جریان فوق­بحرانی با استفاده از نرم‌افزار FLOW-3D پرداخته شده است. با بررسی نتایج حاصل از شبیه­سازی، مدل­ آشفتگی RNG به­علت برخورداری از دقت بیشتر و پائین‌بودن درصد خطای نسبی و خطای مطلق نسبت به­سایر مدل­ها، از میان 4 مدل­ آشفتگی RNG، k-ε، k-ω و LES انتخاب شد. در این مطالعه، دامنه عدد فرود بعد از دریچه به­عنوان موثرترین پارامتر بدون­بعد در استهلاک انرژی از 8/2 تا 5/7 تغییر کرده و مقادیر تنگ­شدگی از طرفین 5 و 5/7 سانتی­متر می­باشد. نتایج حاکی از آن است که در تمامی حالات استفاده از تنگ­شدگی هلالی­شکل، استهلاک انرژی ناشی از تنگ­شدگی به­ترتیب در تنگ­شدگی 5 و 5/7 سانتی­متر براساس افت انرژی نسبت به بالادست 62/24% و 84/29% و نسبت به پائین­دست 14/46% و 42/48% بیشتر از پرش کلاسیک آزاد است. هم‌چنین با بررسی نتایج به­دست آمده مشاهده شد که تنگ­شدگی هلالی­شکل در مقایسه با انقباض ناگهانی، حاصل از مطالعات محققین پیشین، عملکرد بهتری از نظر میزان افت انرژی دارد. براساس نتایج حاصل از شبیه­سازی با افزایش عدد فرود بالادست، افت انرژی نسبت به بالادست و پائین­دست تنگ­شدگی هلالی­شکل افزایش یافته به‌طوری‌که استفاده از المان­های تنگ­شدگی باعث کاهش عدد فرود در پائین­دست مقطع تنگ­شدگی در بازه 6/1 الی 3/2 شده است.

کلیدواژه‌ها

عنوان مقاله [English]

Numerical Simulation of Energy Dissipation in Crescent-Shaped Contraction of the Flow Path

نویسندگان [English]

  • Rasoul Daneshfaraz 1
  • Ehsan Aminvash 2
  • Hamidreza Abbaszadeh 3
1 Professor, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Iran.
2 M.sc student, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Iran.
3 M.sc student, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Iran
چکیده [English]

One of the methods of controlling and reducing flow energy is to use energy dissipating structures through formation of hydraulic jumps. One of these types of structures is the constriction elements in the flow path, which leads to a decrease in the energy of the passing flow. In the present study, the effect of crescent-shaped contraction as an energy dissipating structure in the supercritical flow path has been investigated using FLOW-3D software. Examining the simulation results, the RNG model among the four turbulence models, RNG, k-ε, k-ω and LES was selected due to its higher accuracy and lower relative error and absolute error percentage. In this study, the amplitude of the Froude number after the gate as the most effective dimensionless parameter in energy dissipation varied from 2.8 to 7.5 and the values of stenosis on both sides are 5 and 7.5 cm. The results show that in all cases of using the crescent-shaped contractions, the energy dissapation in 5 and 7.5 cm contractions are respectively 24.62% and 29.84% more than the ones in the classic free jump, based on the energy drop relative to the upstream, and 46.14% and 48.42% more, based on the energy drop relative to the downstream. Also, by reviewing the previous researchs, it was found that the crescent-shaped contractions have a better performance in terms of energy loss compared to the sudden contraction. Based on the simulation results, with increasing the upstream Froude number, the energy dissipation is increased relative to the upstream and downstream of crescent-shaped contraction, so that the use of contraction elements reduces the downstream Froude number of the contracted section in the range of 1.6 to 3/2.

کلیدواژه‌ها [English]

  • Energy dissipation
  • Crescent-shaped contraction
  • Froude number
  • Hydraulic jump
  • Turbulence model

مراجع

Abrishami, J. and Esmaili, K. (1997). Hydraulic Jump in Adverse Channel Slopes with Positive steps: Amirkabir Journal of Science and Research, 20(1), 276-292. (In Farsi)
Babaali, H. Shamsai, A. and Vosoughifar, H. (2015). Computational Modeling of the Hydraulic Jump in the Stilling Basin with Convergence Walls Using CFD Codes: Arab J Sci Eng 40(2),381–395.
Chow, V. R. (1959). Open-Channel Hydraulics. New York: McGraw-Hill.
Daneshfaraz, R. Sadeghfam, S. and Rezazadeh-Joudi, A. (2017). Laboratory Investigation on the Effect of Screen’s Location on the Flow Energy Dissipation: Journal of Irrigation and Drainage Structures Engineering Research, 17(67), 47-62. (In Farsi)
Daneshfaraz, R. Rezazadeh-Joudi, A. and Sadeghfam, S. (2018). Experimental Investigation of Energy Dissipation in the Sudden Chocked Flow with free Surfaces: Journal of Civil and Environmental Engineering, 48(2), 101-108. (In Farsi)
Daneshfaraz, R., Sadeghfam, S., Hasanniya, V. (2019). Experimental Investigation of Energy Dissipation in Vertical Drops Equipped with a Horizontal Screen under Supercritical Flow, Iranian Journal of Soil and Water Research, 50(6), pp. 1421-1436. doi: 10.22059/ijswr.2019.269301.668053
Daneshfaraz, R. MajediAsl, M. Mirzaee, R. and Tayfur, G. (2020a). Hydraulic jump in a rough sudden symmetric expansion channel. AUT Journal of Civil Engineering, doi: 10.22060/ajce.2020.18227.5667
Daneshfaraz, R. Majediasl, M. Mirzaee, R. Parsamehr, P, (2020b). Experimental Study of the Roughness Bed with non-Continuous Trapezoidal Elements on S-Jump Characterestics in the non-Prismatic Rectangular Channel: Sharif Journal Civil Engineering, 36(2), 119-128. (In Farsi)
Daneshfaraz, R. Aminvash, E. Esmaeli, R. Sadeghfam, S. and Abraham, J. (2020c). Experimental and numerical investigation for energy dissipation of supercritical flow in sudden contractions: Journal of Groundwater Science and Engineering, 8(4), 396-406.
Das, R. Pal, D. Das, S. and Mazumdar A. (2014). Study of Energy Dissipation on Inclined Rectangular Contracted Chute: Arab J Sci Eng 39(10),6995–7002.
Dey, S. and Raikar, R.V. (2005). Scour in Long Contractions: Journal of Hydraulic Engineering, 131(12), 1036-1049.
Ebrahimiyan, S. Hajikandi, H. Shafai Bejestan, M. Jamali, S. and Asadi, E. (2020). Studying the effect of trapezoidal channel side slope on the bed shear stress and hydraulic jump characteristics using Flow3D model: Iranian Water Research Journal, 13(4), 103-112. (In Farsi)
Esmaili, K. and Abrishami, J. (2001). Hydraulic Jump over Negative Slopes with Negative Steps: Journal of Advanced Materials in Engineering, 19(2), 97-110. (In Farsi)
Flow Science Inc. (2016) FLOW-3D V 11.2 User’s Manual, Santa Fe, NM, USA.
Ghaderi A, Dasineh M, Abbasi S. (2019). Impact of Vertically Constricted Entrance on Hydraulic Characteristics of Vertical Drop (Numerical Investigation): Journal of Hydraulic, 13(4), 121-131. (In Farsi)
Ghaderi, A., Daneshfaraz, R., Abbasi, S. et al. Numerical analysis of the hydraulic characteristics of modified labyrinth weirs. Int J Energ Water Res 4, 425–436 (2020). https://doi.org/10.1007/s42108-020-00082-5
Gohari, A. and Farhoudi, J. (2009). The Characteristics of Hydraulic Jump on Rough Bed Stilling Basin. in: Proceedings of 33rd IAHR Congress, Water Engineering for a Sustainable Environment, 9-14 Aug., Vancouver, British Columbia, Canada
Hager, W. H. and Dupraz, P.A. (1985). Discharge characteristics of local, discontinuous contractions: Journal of Hydraulic Research, 23(5), 421-433.
Hasannia, V. Daneshfaraz, R. Sadeghfam, S. (2021). Experimental investigation of hydraulic parameters of vertical drop equipped with combined screens: Amirkabir Journal of Civil Engineering, 52 (10), 1-14. (In Farsi)
Henderson, F. M. (1966) Open channel flow. New York: Macmillan.
Izadjoo, F. and Shafaei Bajestan, M. (2005). Hydraulic Jump Characteristics on a Trapezoidal Corrugated Bed: The Scientific Journal of Agriculture, 27(Special Issue of Water Science Engineering), 107-122. (In Farsi)
Jan, C. D. and Chang, C. J. (2009). Hydraulic Jumps in an Inclined Rectangular Chute Contraction: Journal of Hydraulic Engineering, 135(11), 949-958.
Katorani, S. and Kashefipoor, S. M. (2014). Effect of the Geometric Characteristics of Baffled and Bed Slopes of Drop on Hydraulic Flow Conditions in Baffled Apron Drop. Irrigation Sciences and Engineering, 37(2), 51-59. (In Farsi)
Lotfi, N and Jafarzadeh, M. R. (2017). Investigation of the effects of convergence and roughness on the characteristics of hydraulic jump in narrowing channels. In: Proceedings of  16th Iranian Hydraulics Conference, 6-7 Sep., Ardabil, Iran. (In Farsi)
Nayebzadeh, B. Lotfollahi-yaghin, M. and Daneshfaraz, R. (2019). Experimental study of Energy Dissipation at a Vertical Drop Equipped with Vertical Screen with Gradually Expanding at the Downstream: Amirkabir Journal of Civil Engineering, 52(12), 7-7. doi: 10.22060/ceej.2019.16493.6265 (In Farsi)
Nazari Ali Abadi, kh. Akhtari, A. A. and Gord Noshahri, A. (2017). Effect of Rectangular Strip Roughness on Hydraulic Jump Characteristic in Diverging Rectangular Sections With FLOW-3D Software: Modares Civil Engineering journal, 17(4), 251-262. (In Farsi)
Sadeghfam, S. Akhtari, A.A. Daneshfaraz, R. and Tayfur, G. (2015). Experimental investigation of screens as energy dissipaters in submerged hydraulic jump: Turkish Journal of Engineering and Environmental Sciences, 38(2), 126-138.
Shabani Chafjiri, A. and Jafarzadeh, M. R. (2020). Experimental study of hydraulic jump characteristics in an inclined convergent channel: Modares Civil Engineering journal, 20(2), 27-40. (In Farsi)
Shojaeian, Z. Hosseinzadeh Dalir, A., Farsadizadeh, D. and Salmasi, F. (2011). Investigation of Hydraulic Jump Characteristics In Divergent Rectangular Sections On Inverse Slope: Water and Soil Science (Agriculture Science), 21(3), 49-60. (In Farsi)
Wu, B. and Molinas, A. (2001). Chocked Flows through Contractions: Journal of Hydraulic Engineering, 127(8), 657-662.
Yarnell, D. L. (1934). Bridge piers as channel obstructions. Washington: U.S. Dept. of Agriculture

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