عنوان مقاله [English]
Meandering river bend migration is a common phenomenon which destroys agricultural lands and civil infrastructures around the river. The main cause of such migration is due to developing a secondary flow within the bend in which a helicoidally circulation is developed and as a results the scour hole at the outer bank toe is created which causes collapse of the outer bank and its migration. Over the last decade many countermeasures against such scour have been developed. These measures modify the flow within the bend redistribute the local bed shear stress for the purpose of reducing the toe bank scour. Triangular vanes are one of such structures that help stabilize the outer bank by modifying the flow pattern in the river bend to prevent the scouring of the outer bank. Triangular vanes have been studied successfully by Bhuiyan et al. (2010) in a sinuosity river path and in a 90 degree flume bend by Bahrami-Yarahmadi and Shafai Bejestan (2016). Based on these studies this measure, if designed properly, not only can shift the scour from the outer bank toe to the middle of the river, it transport sediment to the downstream of the vane and deposited in between the vanes which create a new bank. The structure has been defined environment friendly since it create an environment suitable for aquatic animals. The aim of the present study is to investigate the application of triangular vanes in a 180 degrees of Jangiyeh bend in Karoon River south of Ahvaz and to determine the bets distance for installing the vanes.
1- Bahrami Yarahmadi, M.. and Shafai Bejestan, M.., 2014. Bed Topography Variations in a 90° Mild Bend Due to Triangle-Shaped Spur Dike. Modares Journal of Civil Engineering, 14(3)165-175.(in Persian).
2- Bahrami Yarahmadi, M., Shafai Bejestan, M. 2016 a. 'Comparison of Erosion and Sedimentation Patterns Facilitated by a Spur Dike and a Triangular-Shaped Vane Structures in a 90° Mild Bend under the Influence of Different Froude Numbers', Journal Managmen System, 8(27):31-42. (in Persian).
3- Bahrami Yarahmadi. M. and Bejestan, M.S., 2016 b. Sediment management and flow patterns at river bend due to triangular vanes attached to the bank. Journal of Hydro-environment Research, 10, pp.64-75.
4- Bahrami Yarahmadi. M. and Shafai Bejestan, M., (2016), “Study of the Effect of Length Variations of Triangular-Shaped Vanes on Erosion and Sedimentation Pattern in a 90° Mild Bend” , journal of Civil Engineering, 27(1): 87-100. (in Persian).
5- Bhuiyan, f. Hey, R. D., Wormleaton, P. R.2010. Bank-Attached vanes for Bank Erosion Control and Restoration of River Meanders. Journal of Hydraulic Engineering. 136 (9), 583-596.
6- Hemmati, M., Gomeshi, M., Kashefipour, S. (2013). 'Experimental Investigation on the Effect of the Bendway Weir Angle on the Erosion and Sedimentation Pattern in Meandering River', Iran Water Resources Research, 8(3), pp. 66-76.
7- Hey, R. D. 1992. River Mechanics and Habitat Creation. Institute of Fisheries Management, Nottingham, UK. 271-275
8- Hey, R. D. 1996. Environmentally Sensitive River Engineering. Blackwell Science, Oxford, UK. 80-105
9- Shafai Bejestan, M.,(2012). Physical-Hydraulic Models. Shahid Chamran University of Ahvaz Publications. (in Persian).
10- Shields, F.D. 2002. Design of Habitat Structure for Open Channels. Journal of Water Resources Planning and Management. 109 (4), 331-344
11- Zahiri. J., 2012. Investigation on Flow Hyraulics & Riprap Stability around Spur Dike in 90° Bend. Ph.D. Shahid Chamran University of Ahvaz. Iran. (in Persian).