Investigation of Flow Dynamics Around a Combination of Different Head Shapes of Spur Dikes

Abstract

Spur dikes are widely used as river training structures throughout the globe to improve navigation, strengthen flood protection, and save erodible banks. This study investigates the flow behaviour of multiple spurs using similar and different head shapes instead of adding an extra structure. The novelty of the study lies in finding out the best combination of head shapes among circular (C), rectangular (R), and triangular (T) that can reduce the responsible factors of scouring and erosion. The responsible factors for scour and erosion include high magnitude velocity, pressure, turbulence kinetic energy (TKE), Reynold stresses, and wall shear stresses. Nine combinations (3 same, i.e., CCC, RRR, and TTT and six different, i.e., CRC, CTC, RCR, RTR, TCT, TRT) of spurs were investigated using Computational Fluid Dynamics (CFD) code FLUENT. Firstly, in the analysis of similar head shapes, more reduction in the values of scour and erosion responsible factors were observed in CCC combination (20% in velocity, 45% in pressure, 41% in TKE, and 43% in normal Reynold stresses). Finally, the reduction was further improved in analysing different head shapes. The CTC combination showed the most effective results in reducing the prescribed factors (43% in velocity, 57% in pressure, 51% in TKE, and 54% in normal Reynold stresses) compared to both combinations of head shapes. Therefore, to protect riverbank and spur head failure due to severe turbulent flow, the combination of spurs (CTC) could be preferred.

Keywords

• combination of spurs
• numerical simulation
• open channel flow
• riverbank protection
• wall shear stress