| تعداد نشریات | 282 |
| تعداد نشریات سازمان | 80 |
| تعداد شمارهها | 3,196 |
| تعداد مقالات | 35,423 |
| تعداد مشاهده مقاله | 52,248,648 |
| تعداد دریافت فایل اصل مقاله | 91,780,735 |
بررسی عددی کاهش آبشستگی پیرامون پایه پل استوانه ای با استقرار گروه زوج صفحات مستغرق | ||
| تحقیقات مهندسی سازه های آبیاری و زهکشی | ||
| دوره 22، شماره 85، فروردین 1401، صفحه 91-114 اصل مقاله (1.34 M) | ||
| نوع مقاله: مقاله پژوهشی | ||
| شناسه دیجیتال (DOI): 10.22092/idser.2022.357739.1502 | ||
| نویسندگان | ||
| مهران صادقلو1؛ مهدی حمیدی* 2 | ||
| 1دانش آموخته کارشناسی ارشد مهندسی آب و سازه های هیدرولیکی دانشکده مهندسی عمران، دانشگاه صنعتی نوشیروانی بابل | ||
| 2دانشیار دانشکده مهندسی عمران، دانشگاه صنعتی نوشیروانی بابل | ||
| چکیده | ||
| احداث پلها و سازههای هیدرولیکی در مسیر جریان رودخانهها، رخداد آبشستگی در اطراف پایههای پل را در پی دارد. بدین منظور طراحی و اجرای اقدامات کاهش آبشستگی از موارد ضروری در مطالعات این حوزه میباشد. در این پژوهش از گروه زوج صفحات مستغرق برای کاهش آبشستگی پایه پل استفاده شدهاست. مدلهای عددی در نرمافزار FLOW-3D شبیهسازی شده و حساسیتسنجی ابعاد مش، مدلهای آشفتگی و زمان تعادل آبشستگی در مدل عددی بررسی شدهاند. برای صحتسنجی مدل عددی، نتایج تحلیل عددی با دادههای آزمایشگاهی مقایسه و مقادیر خطاهای نسبی تعیین گردیدند. بیشینه خطای 10 درصدی نشان از عملکرد مناسب مدل عددی در تخمین مقادیر بیشینه آبشستگی دارد. بهمنظور طراحی مناسب گروه زوج صفحات مستغرق؛ اثر زاویه استقرار، موقعیت و ارتفاع صفحات بر مقادیر بیشینه آبشستگی و الگوی جریان پیرامون پایه پل بررسی گردیدند. نتایج نشان داده است که موقعیت قرارگیری صفحات در حالت 0D,1D,2D با زاویه استقرار (θ) 30 درجه مناسبترین حالت بوده که تاحدود %32 مقادیر بیشینه آبشستگی (dsmax) را کاهش میدهد. همچنین افزایش ارتفاع صفحات بیش از ارتفاع بستر رسوبی، موجب کاهش روند کاهشی مقادیر بیشینه آبشستگی میشود. | ||
| کلیدواژهها | ||
| الگوی جریان؛ زاویه استقرار صفحات مستغرق؛ کاهش آبشستگی؛ مدل آشفتگی؛ FLOW-3D | ||
| عنوان مقاله [English] | ||
| Numerical investigation of the cylindrical bridge pier scour reduction by installing a group of two submerged vanes | ||
| نویسندگان [English] | ||
| Mehran Sadeqlu1؛ Mehdi Hamidi2 | ||
| 1Department of Water and Hydraulic Structures Engineering, Faculty of Civil Engineering, Babol Noshirvani University of Technology, Babol, Iran | ||
| 2Associate Professor, Faculty of Civil Engineering, Babol Noshirvani University of Technology, Babol, Iran. | ||
| چکیده [English] | ||
| Introduction The construction of hydraulic structures such as bridge piers in river beds changes the hydrodynamics of the flow and is associated with the scouring phenomenon. This process has been investigated by many researchers with numerical and laboratory methods. The implementation of scouring reduction measures has also been considered in addition to investigating this phenomenon, due to the destructive changes of scouring on the morphology and the river bed shape. In general, these measures are divided into two general categories, direct and indirect, which the use of submerged vanes is one of these reduction measures. Based on less attention to this scour reduction measure; in this study, the effect of a group of two submerged vanes on reducing scour around the cylindrical bridge pier with a numerical approach of the FLOW-3D model is investigated. Dimensional analysis showed that the position angle of the vanes, the location, and the height of the vanes are effective parameters. According to the results, the installation of submerged vanes in all cases reduces scour and the position angle of 30 degrees, in location 0D,1D,2D, and the height of the vanes equal to the sedimentary bed leads to the greatest reduction of scour. Methodology In this research, the flow-3d numerical model has been utilized to analyze the scouring phenomenon around the cylindrical bridge pier. In order to validate the numerical model, first, the sensitivity of the mesh dimensions was performed and the 8.5 mm mesh size was selected. Then the analysis of the geometric model for the bridge pier was conducted with different turbulence models k-ε, k-ε RNG, and LES, and the numerical results were compared with experimental data. It was found that the numerical results of the LES model are the most consistent with the experimental data, so this turbulence model has been used for the conditions of bridge pier with submerged vanes. Different times for scour hole development were investigated to determine the processing time of the numerical model and the computational cost, and finally, it was observed that the scour equilibrium time of 500 seconds is suitable for numerical analysis, and after this time the maximum scour values remain almost constant. Results and Discussion By increasing the position angle of the two submerged vanes up to 30 degrees, the amount of scour depth decreases. But by increasing it by 30 degrees, this trend decreases and does not follow a specific trend. The most suitable position of the group of two submerged vanes is in 0D,1D,2D location, and the location of 2D,3D,4D has the least effect, which reduces the distance between the vanes from the upstream of the channel to the bridge pier, the separation point of boundary layer moves to the bridge pier, thus reducing the thickness of the boundary layer. Therefore, by reducing the distance between the vanes and the bridge pier, the intensity of shear stress to dig bed sediments around the bridge pier is reduced and as a result, the effect of submerged vanes and their protection from erodible bed against scouring phenomenon increases. It was found that the presence of submerged vanes in all cases reduces the maximum scour depth, but this amount of reduction is not the same due to the different positions of the vanes. Observing the flow pattern, it can be concluded that the velocity upstream of the pier is negative and rotational flows are formed in this region, which are the horseshoe vortices that are one of the reasons for the formation of scouring holes. Conclusions In all cases of installation of submerged vanes before bridge pier, scour depth was reduced because the presence of vanes caused local scouring around the vane itself and the washed sediment particles were transported by the flow to the scour hole created upstream around the bridge pier. On the other hand, in all locations, by increasing the position angle of the two submerged vanes, the transverse area is more affected by the two vanes, and a stronger drag force is applied to them. In other words, the resistance to current increases, the flow moves away from the bridge pier, and also fewer bed particles are transported around the bridge pier. As the height of the vanes increases, the intensity of the flow colliding with the vanes increases, and as a result, the amount of scouring depth upstream of the vanes increases, and despite the reduction of scouring upstream of the bridge pier, the performance of these vanes decreases. | ||
| کلیدواژهها [English] | ||
| Flow pattern, Position angle of submerged vanes, Scour reduction, Turbulence model, FLOW-3D | ||
| مراجع | ||
|
Abdi, Ch., Vaghefi, M. & Safarpoor, Y. (2022). Numerical simulation of the flow pattern around a single bridge pier with upstream of submerged vanes in sharp 180-degree bend with an alluvial bed under the influence of submerged vanes and the bridge pier. Modares Civil Engineering journal, 22(6), 88-98 (In Persian).
Amiri, T. & Ahmadi, P. (2018). Numerical study of the effect of group submerged vanes on the bridge pier scour using SSIIM software. In 17th National Hydraulic Conference. Sep. 4-6. University of Shahrekord, Iran.
Biabani, S., Hamidi, M. & Neya, B.N. (2019). Numerical simulation of the chute convergence effects on forming the transverse wave in flood evacuation systems. Journal of Hydraulics, 14(3), 67-84 (In Persian).
Biabani, S., Hamidi, M. & Neya, B.N. (2021) Numerical simulation of the pier geometry effects on forming the transverse wave in converged spillways. International Journal of Modern Physics C. 32(01), 2150003
Ebrahimi, T., Hamidi, M., Rahmani, F.A. & Khavasi, E. (2021). Numerical investigation of scour around a cylindrical pier in laboratory scale using Euler-Lagrange approach. Amirkabir Journal of Mechanical Engineering. 53(Special Issue 1), 411-426 (In Persian).
Emamgholizadeh, S. & Nohani, E. (2017). Application of the submerged vanes on reduction of local scour around the bridge abutment with rounded nose. Irrigation and Drainage Structures Engineering Research, 18(68), 113-128 (In Persian).
Flow-3D, user manual (Version 9.3), Flow Science In, 2008.
Ghorbani, B. & Kells, J. (2008). Effect of submerged vanes on the scour occurring at a cylindrical pier. Journal of Hydraulic Research, 46(5), 610-619.
Khademi, Kh., Shafaee, M.B. & Ghomeshi, M. (2014). Flow pattern investigation at bridge abutment with and without installed submerged vane. Irrigation Sciences and Engineering. 37(1), 33-42 (In Persian).
Koohsari, A. & Hamidi, M. (2022). Experimental study of the effect of mining materials downstream of bridge pier on scour profile with optimizing distance approach. Journal of Water and Soil Conservation, 28 (3), 1-25 (In Persian).
Mohammadiun, S., Salehi, S.A.N., Parhizkar, H. & Vahabi, H. (2018). Numerical evaluation of submerged vanes application in sedimentation and erosion potential of open-channel junctions flow. Amirkabir Journal of Civil Engineering. 50(3), 567-578 (In Persian).
Odgaard, J.A. & Kennedy, J.F. (1983). Bed riverbank protection by submerged vanes. Journal of Hydraulic Engineering, 132, 1161-117.
Palau-Salvador, G., Stoesser, T. & Rodi, W. (2008). LES of the flow around two cylinders in tandem. Journal of Fluids and Structures. 24, 1304-1312.
Parchami, L., Asghari, S.A.P. & Shafai, M.B. (2017). Experimental investigation of submerged vanes shape effect on bridge pier scouring. Water and Soil Science. 27(1), 29-41 (In Persian).
Pasiok, R. & Stilger-Szydło, E. (2010). Sediment particles and turbulent flow simulation around bridge piers. Archives of Civil and Mechanical Engineering. 10, 67-79.
Raudkivi, A.J. (1998). Loose boundary hydraulics. Rtterdaom: Press the Netherlands.
Raudkivi, A.J. & Ettema, R. (1983). Clear-water scour at cylindrical piers. Journal of Hydraulic Engineering. 109.
Royani, P., Hosseini, S.H., Azhdary, Kh. & Emamgholizadeh, S. (2021). Numerical investigation of flow pattern, bed profile and shear stress around the rectangular bridge pier using Flow 3D. Iranian Journal of Irrigation and Drainage. 15(5), 1153-1171 (In Persian).
Shojaee, P., Farsadizadeh, D., Hoseinzadeh, A.D., Salmasi, F. & Ghorbani, M.A. (2012). Application of submerged vanes at cylindrical bridge pier as a scour countermeasure. Water and Soil Science. 22(1), 91-109 (In Persian).
Zarrati. A.R. Gholami, H. & Mashahir, M.B. (2004). Application of collar to control scouring around rectangular piers. Journal of Hydraulic Research, 42(1), 97-103. | ||
|
آمار تعداد مشاهده مقاله: 806 تعداد دریافت فایل اصل مقاله: 392 |
||