Numerical study of the effect of discharge on flow pattern around a submerged spur dike in an open channel

Subject Areas : Subjects

Mohammad Vaghefi ¹ (استادیار سازه‌های هیدرولیکی، گروه مهندسی عمران، دانشگاه خلیج فارس، بوشهر)
Afshin Eghbalzadeh ² (استادیار سازه‌های هیدرولیکی، گروه مهندسی عمران، پژوهشکده تحقیقات پیشرفته آب و فاضلاب، دانشگاه رازی کرمانشاه)
Mokhtar Rostamnezhad ³ (دانش آموخته کارشناسی ارشد، گروه مهندسی عمران، دانشگاه آزاد اسلامی بوشهر)

Received: 2016-06-25 Accepted : 2016-06-25 Published : 2016-06-21

Keywords: Numerical Simulation, Flow-3D, Submerged Spur dike, Free surface,

Abstract :

One of the important purposes of river engineering science is to protect river banks from erosion phenomenon and to prevent shifting of the main channel path. Spur dike is a hydraulic structure which has a lot of applications for stabilizing river banks and increasing water depth. According to widespread use of this structure, it is important to understand the flow pattern around it. Since flow pattern around a spur dike is complex and fully 3D, 3D simulation was done in this study. FLOW-3D software was employed to simulate the flow around a submerged spur dike. VOF method was used for free surface simulation and RNG k-ε model was used for turbulence modeling. Based on comparison of numerical and experimental results for stream wise velocity component and flow depth, it was concluded that numerical model could simulate the flow parameters with relatively high accuracy. In following, the effect of discharge increase on velocity profiles and flow free surface was investigated. According to obtained results, maximum longitudinal velocity Infront of the spur dike nose and flow depth at the upstream of spur dike increased with discharge increase. In lower discharges, the changes rate was more and vice versa. Also, the ratio of the flow depth at the upstream and the flow depth at the downstream increased with discharge increase.

References:

1-   حسنی، م. " مطالعه الگوی جریان کم‌عمق چرخشی در اطراف آبشکن‌ها با استفاده از مدل فیزیکی و ریاضی"، پایانامه کارشناسی ارشد، دانشگاه تهران 1380.

2-     ﻧﯿﺸﺎﺑﻮری، ﺻﺎلحی. "ﭘﯿﺶﺑﯿﻨﯽ ﻣﯿﺪان ﺟﺮﯾﺎن در اﻃﺮاف آﺑﺸﮑﻦﻫﺎ"،ﭼﻬﺎرﻣﯿﻦ ﮐﻨﻔﺮاﻧﺲ ﻫﯿﺪروﻟﯿک ایران  1382. 

3-   نوربخش س م، قدسیان م، واقفی م. "بررسی اثر نسبت طول بال به جان آبشکن سرسپری مستغرق در تغییرات توپوگرافی بستر." دهمین کنفرانس هیدرولیک ایران، دانشگاه گیلان 1390.

4-   واقفی م، قدسیان م و صالحی نیشابوری س ع ا.  بررسی تغییرات زمانی آبشستگی اطراف آبشکن Tشکل در قوس 90 درجه. مجله پژوهش های حفاظت آب و خاک، جلد شانزدهم، شماره اول، 53-62. 1388.

5-   واقفی، م.، ک. بیروتی و م. اکبری. 1392. "مطالعه عددی اثر طول جان آبشکن سرسپری مستقر در مسیر مستقیم با بستر صلب بر الگوی جریان". دوازدهمین کنفرانس هیدرولیک ایران. دانشکده کشاورزی و منابع طبیعی دانشگاه تهران 1392.

6-   واقفی، م. و پ. رادان. "مطالعه عددی آبشستگی و الگوی جریان در نهر قوسی 90 درجه با وجود آبشکن T شکل با تغییر در شعاع انحنای قوس". مجله علمی پژوهشی مهندسی منابع آب. 7(23): 37-51. 1393.

7-   واقفی، م.، ه. زره پوش شیرازی و م. اکبری. "مطالعه عددی تأثیر شعاع انحنا بر الگوی جریان پیرامون آبشکن سرسپری مستغرق". مجله علمی پژوهشی آبیاری و آب. 5(18): 145-156. 1393.

8-      Azinfar, H. (2006): Flow resistance due to a single spur dike in an open channel,

9-      Theses Department of Civil and Geological Engineering ,University of Saskatchewan.

10-  Azinfar, H. and Kells, J.A. 2007. Backwater effect due to a single spur dike. Canadian Journal of Civil Engineering, NRC Press, 34(1): 107-115.

11-  Azinfar, H. and Kells, J.A (2009): Flow resistance due to a single spur dike in an open channel, Journal of Hydraulic Research, 47:6, 755-763.

12-  Belz, J.U., Busch, N., Engel, H. and Gasber, G. 2001. Comparison of river training measures in the Rhine catchment and their effects on food behavior. Water and Maritime Engineering, Proceedings of the Institution of Civil Engineers, London, UK, 148(3): 123- 132.

13-  Giri, S., Shimizu ,Y., and Surajate,B., “Laboratory Measurement and Numerical Simulation of Flow and Turbulence in a Meandering-like Flume with Spurs”, Flow Measurement and Instrumentation, 15(2004) 301-309.

14-  Jia, Y. and Wang, S.S.Y. 2000. Numerical study of turbulent flow around submerged spur dikes 4th International Conference on Hydro-Science and Engineering, Korea Water Resources Association, Seoul, South Korea, CD-ROM, 7 p.

15-  McCoy, A., Constantinescu, S.G., and Weber, L. 2006a. Exchange processes in a channel with two vertical emerged obstructions. J. of Flow. Turbulence. Combustion.pp: 97-126.

16-  Molinas, A. and Kheireldin, K., Wu, B., 1998., Shear Stress Around Vertical Wall Abutments. Journal of Hydraulic Engineering, Vol. 124, No. 8.

17-  Nagata, N., Hosoda, T., Nakato, T., and Muramoto, Y. (2005). ”Three-Dimensional Numerical Model for Flow and Bed Deformation around River Hydraulic Structures.” J. Hydraul. Eng., 131(12), 1074–1087.

18-  Peng, J., Kawahara, Y. and Tamai, N. 1997.Numerical analysis of three-dimensional turbulent flows around submerged groins. Proc. of 27th IAHR Congress, Theme A, Managing Water, San Francisco, CA, USA, pp. 829-834.

19-  Sharma, K. and Mohapatra, P. (2012). ”Separation Zone in Flow past a Spur Dyke on Rigid Bed Meandering Channel.”J. Hydraul. Eng., 138(10), 897–901.

20-  V. Weitbrecht and G.H. Jirka, “Flow Patterns and Exchange Processes in Dead Zones of Rivers”, IAHR Congress, 2001, Beijing.

21-  Wim S. J. - Uijttewaal “Effect of Groyne Layout on the Flow in Groyne Fields: Laboratory Experiments”, Journal of Hydraulics Engineering. Vol.131 , No 9, 2005, 782- 791.

22-  Yeo, H. K., Kang, J. G., Kim, S. J. (2005). "An Experimental Study on Downstream Recirculation Zone of Single Groyne Cndition" XXXI IAHR Congress, Korea, PP. 5101-5110.