بررسی عددی تأثیر همزمان شیب دیواره کناری و شکل هندسی مخزن بر خصوصیات سیلاب ناشی از شکست سد در حالت بستر خشک

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانش‌آموخته کارشناسی‌ارشد، گروه مهندسی عمران، دانشکده فنی مهندسی، دانشگاه محقق اردبیلی، اردبیل، ایران

2 دانشیار، گروه مهندسی عمران، دانشکده فنی مهندسی، دانشگاه محقق اردبیلی، اردبیل، ایران

چکیده

سدها جزو سازه‌هایی هستند که علیرغم اثرات محیط­زیستی عمدتاً به‌منظور تأمین آب و انرژی ساخته می‌شوند. شکست سد سبب ایجاد جریان عظیمی می‌شود که سیلاب در نواحی پایین‌دست را به‌ دنبال دارد. به همین دلیل تعیین خصوصیات جریان شکست سد از جمله عمق جریان و سرعت انتشار موج از اهمیت بالایی برخوردار است. در این پژوهش تأثیر هم‌زمان شکل هندسی مخزن در پلان و شیب دیواره کناری مخزن بر الگو و چگونگی حرکت موج سیلابی ناشی از شکست سد به‌صورت مدل‌سازی عددی سه‌بعدی با استفاده از نرم‌افزار Flow3D انجام شد. بدین منظور از چهار شکل مختلف مخزن در پلان شامل مخزن عریض، ذوزنقه‌ای، L شکل و طویل با شیب‌های دیواره کناری 30، 45، 60 و °90 و با در نظر گرفتن بستر خشک پائین‌دست استفاده شد. نتایج حاصل از مدل‌سازی سه‌بعدی عددی بیانگر این بود که در تمامی مخازن موردمطالعه با کاهش شیب کناری دیواره مخزن، نوسانات سطح آب به دلیل تشکیل دو موج منفی که بر روی شیب دیواره مخازن گسترش یافته و در محل خط مرکزی مخازن به هم رسیده، افزایش یافته است. همچنین تأثیر شکل هندسی مخازن عریض و ذوزنقه‌ای بر روی خصوصیات جریان ناشی از شکست سد، بیشتر از تأثیر کاهش شیب دیواره کناری این مخازن بوده است. درحالی‌که در مخازن طویل و L شکل، کاهش شیب دیواره کناری این مخازن تأثیر فراوانی بر روی خصوصیات جریان ناشی از شکست سد دارد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Numerical Study of Simultaneous Effect of the Sidewall Slope and the Geometric Shape of Reservoir on the Flood Characteristics Caused by Dam Break on Dry Bed Condition

نویسندگان [English]

  • Alireza Asadpour Ardabil 1
  • Atabak Feizi 2
1 M.Sc. Alumni, Department of Civil Engineering, Faculty of Engineering, University of Mohaghegh Ardabili, Ardabil, Iran
2 Assoc. Professor, Department of Civil Engineering, Faculty of Engineering, University of Mohaghegh Ardabili, Ardabil, Iran
چکیده [English]

Introduction: Dams are important structures built primarily for water and energy supply. The dam break creates a catastrophic flow leading to flooding in downstream. For this reason, determination of the characteristics of the dam break, including the depth of flow and the velocity of wave propagation, is important. In this study, the simultaneous effects of the geometric shape of the reservoir on the plan and the slope of the sidewall of the reservoir on the characteristics of flows due to dam break were investigated.
Materials and Methods: 3D numerical modeling was performed using the Flow3D software. Four different reservoir shapes, namely wide reservoir, trapezoidal reservoir, L-shaped reservoir, and long reservoir with sidewall slopes of 30, 45, 60 and 90° were used regarding the dry bed downstream. Mesh sizes 0.01, 0.03, 0.05, and 0.1 m were applied to the model to analyze the mesh size sensitivity of the numerical model. Besides the mesh size sensitivity analysis, the sensitivity analysis of the model to turbulence models was also performed.
Results: According to the results, in reservoirs with wide and trapezoid geometry, due to the geometric shape, cross-waves are formed in the channel connected to these reservoirs and cause severe fluctuations in the water level of different parts of the downstream channel. While in long and L-shaped reservoirs, much fewer fluctuations occur due to the reservoir and the downstream channel alignment. In all studied reservoirs, water level fluctuations increased in different parts of the downstream channel and points inside the reservoir, decreasing the lateral slope of the reservoir wall. The effect of fluctuations on the water level caused by this factor in different parts of the downstream channel connected to long and L-shaped reservoirs is more than wide and trapezoidal reservoirs. However, the geometric shape of the reservoirs is a factor influencing the fluctuations in wide and trapezoidal reservoirs. In addition, variations in the in-depth velocity profiles at different downstream channel points connected to different reservoirs with different lateral slopes showed that with decreasing the slope of the sidewall of the reservoirs, the average velocity increased at the downstream points of the gate. It reached its maximum value at an angle of 30° to the reservoir's sidewall. Finally, changes in the flow hydrograph at the gate location showed that the flow rate decreases with decreasing angle of the reservoir sidewall in wide and trapezoidal reservoirs; however, the flow rate increases in long and L-shaped reservoirs.
Conclusion: The numerical 3D modeling indicated that in all studied reservoirs with reducing the lateral slope of the reservoir wall, water level fluctuations caused by the formation of two negative waves spread on the slope of the reservoir wall were increased at the central line of the congested reservoirs. Additionally, the effect of the geometric shape of wide and trapezoidal reservoirs on the flow characteristics of dam break was more than the effect of reducing the slope of the sidewall of these reservoirs; however, in long and L-shaped reservoirs, reduction of the slope of the sidewall of these reservoirs significantly affected the flow characteristics of the dam break.

کلیدواژه‌ها [English]

  • Dam Break
  • Reservoir Geometry
  • Sidewall Slope of Reservoir
  • 3D Numerical Simulation
Amini, A., Arya, A., Eghbalzadeh, A., Javan, M. (2017). Peak flood estimation under overtopping and piping conditions at Vahdat Dam, Kurdistan Iran Arab. J. Geosci., 10(6), 127.
Aureli, F., Dazzi, S., Maranzoni, A., Mignosa, P. and Vacondio, R. (2015). Experimental and numerical evaluation of the force due to the impact of a dam-break wave on a structure. Adv. Water Resour., 76, 29–42. DOI:10.1016/j.advwatres.2014.11.009
Costa, J. E. (1985) Floods from dam failures. US Geological Survey, Open-File Rep. No. 85-560, Denver, 54 pp. DOI: 10.3133/ofr85560
Costabile, P., Macchione, F., Natale, L. and Petaccia, G. (2015). Comparison of scenarios with and without bridges and analysis of backwater effect in 1-D and 2-D river flood modeling. Computer Model. Eng. Sci., 109-110(2), 81-103. DOI:10.3970/cmes.2015.109.081
Feizi Khankandi, A., Tahershamsi, A. and Soares-Frazão, S. (2012). Experimental investigation of reservoir geometry effect on dam-break flow. J. Hydraul. Res., 50(4), 376–387. DOI:10.1080/00221686.2012.690974
Feizi, A. (2018). Hydrodynamic study of the flows caused by dam break around downstream obstacles. Open Civil Eng. J., 12(1), 225–238. DOI: 10.2174/1874149501812010225
FLOW 3D User’s Manual. (2011). Version 10.0. Flow Science Inc.
Froehlich, D. C. (1996). Peak outflow from breached embankment dam. J. Water Resour. Plan. Manag., 122(4), 317-319. DOI: 10.1061/(asce)0733-9496(1996)122:4(317)
Hooshyaripor, F., Tahershamsi, A. and Razi, S. (2017). Dam break flood wave under different reservoir’s capacities and lengths. Sādhanā, 42(9), 1557–1569. DOI: 10.1007/s12046-017-0693-x
Issakhov, A. and Imanberdiyeva, M. (2020). Numerical study of the movement of water surface of dam break flow by VOF methods for various obstacles. Int. J. Nonlinear Sci. Numer. Simul., 21(5), 475–500. DOI: 10.1515/ijnsns-2018-0278
Issakhov, A., Zhandaulet, Y. and Nogaeva, A. (2018). Numerical simulation of dam break flow for various forms of the obstacle by VOF method. Int. J. Multiphase Flow, 109, 191–206. DOI:10.1016/j.ijmultiphaseflow.2018.08.003
Javadian, M., Kaveh, R. and Mahmoodinasab, F. (2016). A study on experimental model of dam break problem and comparison experimental results with analytical solution of Saint-Venant equations. Int. J. Adv. Biotechnol. Res., 7, 1239-1245.
Kocaman, S., Güzel, H., Evangelista, S., Ozmen-Cagatay, H. and Viccione, G. (2020). Experimental and numerical analysis of a dam-break flow through different contraction geometries of the channel. Water, 12(4), 1124. DOI: 10.3390/w12041124
MacDonald, T. C. and Langridge-Monopolis, J. (1984). Breaching characteristics of dam failures. J. Hydraul. Eng., 110(5), 567–586.
Miraki, A., Bahrami, J. and Amini, A. (2020). Investigation of flood characteristics due to dam failure in the narrow section of the Rive. Environ. Water Eng., 6(4), 388-401. DOI: 10.22034/jewe.2020.245577.1411 [In Persian].
Monteiro, L. R., Lucchese, L. V. and Schettini, C. E. B. (2019). Comparison between hydrostatic and total pressure simulations of dam-break flows. J. Hydraul. Res., 58(5), 725–737.  DOI: 10.1080/00221686.2019.1671509.
Najar, M. and Gul, A. (2022). Investigating the Influence of Dam-Breach Parameters on Dam-Break Connected Flood Hydrograph. Teknik Dergi. 796334. DOI: 10.18400/tekderg.
Ozmen-Cagatay, H. and Kocaman, S. (2011). Dam-break flow in the presence of obstacle: experiment and CFD simulation. Eng. Appl. Comput. Fluid Mechanics, 5(4), 541–552. DOI:10.1080/19942060.2011.11015393
Pilotti, M., Tomirotti, M., Valerio, G. and Bacchi, B. (2010). Simplified method for the characterization of the hydrograph following a sudden partial dam break. J. Hydraul. Eng., 136(10), 693-704. DOI: 10.1061/(asce)hy.1943-7900.0000231
Singh, K. P. and Snorrason, A. (1984). Sensitivity of outflow peaks and flood stages to the selection of dam breach parameters and simulation models. J. Hydrol. Eng., 68(1-4):295–310. DOI: 10.1016/0022-1694(84)90217-8
Soares-Frazão, S. (2007). Experiments of dam-break wave over a triangular bottom sill. J. Hydraul. Res., 45(sup1), 19–26. DOI:10.1080/00221686.2007.9521829
Soares-Frazão, S. and Zech, Y. (2002). Dam break in channels with 90° bend. J. Hydraul. Eng., 128(11), 956–968. DOI: 10.1061/(asce)0733-9429(2002)128:11(956)
Soares-Frazão, S. and Zech, Y. (2007). Experimental study of dam-break flow against an isolated obstacle. J. Hydraul. Res., 45(sup1), 27–36. DOI:10.1080/00221686.2007.9521830
Tahershamsi, A., Hooshyaripor, F., and Razi, S. (2017). Reservoir’s geometry impact of three dimensions on peak-discharge of dam failure flash flood. Scientia Iranica, 25(4), 1931–1942. DOI:10.24200/sci.2017.4467
Toro, E. F. (2001). Shock capturing methods for free flows. John Wiley and Sons Publications, USA. 326 pp.
Wrachien, D. and Mambretti, S. (2009). Dam-break problems, solutions and case studies. WIT Transactions on State-of-the-art in Science and Engineering Publications, UK. 368 pp.