The Modelling and Examination of Flow in the Vicinity of Spur dikes

Various methods are applied in order to prevent the damages caused by natural scouring. One of these methods employed to reduce scouring and erosion is to introduce spur dikes that alter the flow vectors by directing them towards central parts of the channel. Furthermore, installing spur dikes along a channel profile could have negative consequences therefore undertaking a detailed analysis is necessary before application. Ambiguities such as flow behaviour in the vicinity of spur dikes, effects of variation in discharge on normal depth and the influence of a series of single spur dikes on normal depth alongside with other possible effects require examination and comparison with laboratory outputs.Similar researches have been mostly conducted in laboratories; thus, a significant number of the related researches in this scope are experimental. Moreover, a considerable part of the numerical modelling and simulations were performed by other simulators instead of the adopted software CCHE-2D. In order to perform the calibration of the modelling and software, a laboratory model was selected. The laboratory model was simulated and analysed by CCHE-2D software. The results indicate that increasing the length of spur dikes led to a decrease in water level upstream of the spur dike. Conversely, it was observed that the water level downstream of the spur dike rises. As the length of spur dike increases, so does the length of created eddy in the downstream of the spur dike.Additionally, when the spur dikes are set two and four times of their length apart from each other, similar results of river protection are observed; but by increasing the distances between the spur dikes, diverse impacts are detected. Increasing the distances between spur dikes forces the flow to move to the sides of the channels and this is one of the negative consequences of spur dikes.

Keywords:

spur dike , CCHE , numerical modeling , comparison , mesh , flow behavior , channel