Effects of relative curvature on the scour pattern in a 90° bend with a T-shaped spur dike using a numerical method

ABSTRACT

Spur dikes have been usually applied as river-training structures for many years. One of the spur dikes with the proper application in the regulation of rivers is a T-shaped spur dike. In this paper, we study the effects of relative curvature of bend on scour pattern due to installation of a T-shaped spur dike with equal ratio of wing to web length in a 90° channel bend with a moving bed. The spur dike was placed in the outer bank of the middle of the bend at three relative curvatures equal to 2, 3 and 4 in a non-submerged case and 25% of submergence ratio. For analysis the SSIIM 1-1 numerical model was used because it is capable of simulating flows and sediment transport. The k–ϵ turbulence model was used to analyse turbulent flow and find the Reynolds stresses. It is concluded that by increasing the relative curvature of the bend, the maximum sedimentation increases to 73.3% and the maximum scour increases to 6.3%. In the test case of a 25% submerged spur dike, by increasing the relative curvature of the channels, the amount of scour is increased; with submergence of the spur dike in all relative curvatures the maximum scour is reduced and the maximum power of secondary flow decreased by 31%.

Keywords:

• SSIIM Model
• T-shaped spur dike
• 90° bend
• relative curvature
• scour pattern

Disclosure statement

No potential conflict of interest was reported by the authors.