In collaboration with Iranian Watershed Management Association

Document Type : Research Paper

Authors

1 PhD Student Civil Engineering water, South Tehran Branch, Islamic Azad University, Tehran, Iran,

2 Assistant Professor, K.N. Toosi University of Technology, Tehran, Iran

3 Assistant Professor, Central Tehran Branch, Azad University, Tehran, Iran

Abstract

The spur dike has been known as one of the most common organizing constructs of the river to reduce the erosion of coasts and river banks. These structures are developed with the right lengths and angles towards the flow of the natural walls of the river that cause flow deviation from the sides and lead it toward the central river axis. In this experimental study, the flow pattern around the simple series spur dike in the meandering channel with a sloped erodible wall consisting of three consecutive arches with angles of 45, 90 and 45 degrees, has been studied for 40, 35 and 30 liter/sec rates. The results indicate that the collision position of the first line of flow in the near bed to the inner wall of bend no. 2 in discharge 40 liters per second earlier than discharge 35 liters per second and in discharge 35 liters per second earlier than the discharge 30 liter per second. So that the collision position of the first line of flow in the near bed to the inner wall of bend no. 2 in discharge, 40, 35 and 30 liters per second, respectively, in the -18, -15 and -10 degree sections compared to the central arc of the mentioned bend. In conditions of the presence of spur dikes, the vortex dimensions change with the depth of movement, so that moving towards the surface of the water in a fixed discharge, due to the tendency of flow to the outer wall, the slope of the bend wall and increasing the level of contact surface of the spur dike length, the vortex dimensions are increased.

Keywords

  1. Abhari, M.N., M. Ghodsian, M. Vaghefi and N. Panahpur. 2010. Experimental and numerical simulation of flow in a 90° bend. Flow Measurement and Instrumentation, 21: 292-298.
  2. Acharya, A. and G.J. Duan. 2011. Three dimensional simulation of flow field around series of spur dikes. World Environmental and Water Resources Congress. United States of America, 2085-2094.
  3. Aezzi, S., M.J. khanjani and M. Zounemat Kermani. 2018. Two dimensional simulation of flow pattern and bed changes in straight and meandering channels under the effect of spur dike. Iranian Journal of Irrigation and Drainage, 12(4): 970-981 (in Persian).
  4. Elyasi, S., A. Eghbalzade, M. Javan and M. Vaghefi. 2016. Effect of section constriction due to T-shaped spur dike in a bend on flow pattern using FLOW-3D software. Iranian Journal of Irrigation and Drainage, 6(9): 983-993 (in Persian).
  5. Ettema, R. and M. Muste. 2004. Scale effects in flume experiments on flow around a spur dike in flat bed channel. Journal of Hydraulic Engineering, 130(7): 635-646.
  6. Iranshahi, M., M. Ghodsian and M. Vaghefi. 2016. Flow field and scouring around series of triplex spur dikes in sharp bend. Modares Civil Engineering Journal, 16(3): 1-12 (in Persian).
  7. Jamieson, E.C., C.D. Rennie and R.D. Townsend. 2013. 3D flow and sediment dynamics in a laboratory channel bend with and without stream barbs. Journal of Hydraulic Engineering, 139: 154-166.
  8. Keshavarzi, A.R., M. Valizadeh and J. Ball. 2010. Experimental study of the effects of submerged dikes on the energy and momentum coefficients in compound channel. Journal of Scientific and Engineering Research, 2(11): 855-862.
  9. Kumar, , D. Tyagi, L. Aggarwal and M. Kumar. 2018. Comparison of scour around different shapes of groyns in open channel. International Journal of Recent Trends in Engineering and Research, 4(3): 382-392.
  10. Mousavi Naeini, S.A., M. Vaghefi and M. Ghodsian. 2010. Experimental investigation of relative radius on flow pattern around a T-shaped spur dike in 90 degree bend with rigid bed. Bimonthly Journal of Water and Wastewater, 23(1): 15-23 (in Persian).
  11. Nagata, N., T. Hosada and T. Nakato. 2005. Three dimensional numerical model for flow and bed deformation around river hydraulic structures. Journal of Hydraulic Engineering, 131(12): 1074-1087.
  12. Sharma, K. and K.P. Mohapatra. 2012. Separation zone in flow past a spur dyke on rigid bed meandering channel. Hydraulic Engineering, 138(10): 897-901.
  13. Vaghefi, M., M. Shakerdargah, A.R. Fiouz and M. Akbari. 2014a. Numerical investigation of the effect of Froude number on flow pattern around a single T-shaped spur dike in a bend channel. Journal of Scientific and Engineering Research, 3: 351-355.
  14. Vaghefi, M., M. Shakerdargah and M. Akbari. 2014b. Numerical study on the effect of ratio among various amounts of submersion on three dimensional velocity components around T-shaped spur dike located in a 90 degree bend. International Journal of Engineering, Science and Technology, 3: 675-679.
  15. Vaghefi, M., M. Ghodsian and M. Akbari. 2017. Experimental investigation on 3D flow around a single T-shaped spur dike in a bend. Periodica Polytechnica Civil Engineering, 61(3): 462-470.
  16. Vaghefi, M., B. Faraji, M. Akbari and A. Eghbalzadeh. 2018. Numerical investigation of flow pattern around a T-shaped spur dike in the vicinity of attractive and repelling protective structures. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 40(2): 93-108.
  17. Xiufang, Z., M. Pingyi and Y. Chengyu. 2012. Experimental study on flow turbulence distribution around a spur dike with different structure. Procedia Engineering, 28(5): 772-775.
  18. Zare, M. and T. Honar. 2016. The effect of groyne on reduction of the scour depth around bridge piers in river bends. Journal of Water and Soil Science, 19(74): 167-192 (in Persian).
  19. Zhang, H., H. Nakagawa, K. Kawaike and Y. Baba. 2009. Experiment and simulation of turbulent flow in local scour around a spur dike. International Journal of Sediment Research, 24(1): 33-45.