Experimental Investigation of Permeable and Impermeable Groines Performance on Flow Pattern and Bed Topography in Erodible Channel

The erosion of riverbeds is one of the factors that causes changes in the morphology of rivers. Scour depth represents the amount of potential degradation of the flow around hydraulic structures located in the flow path. Therefore, it is necessary to determine the scour depth and flow rate. In this study, the experimental results of bed topography changes and flow patterns around impermeable and impermeable groines are compared. For permeable groines, two types of gabion groines and one and two-row groines with a 90 degree angle to the flow were used. In the use of two-row groine, the two positions are considered parallel and zigzag. Experiments were performed in a rectangular channel with a moving bed of 60 cm width and a flow rate of 28 lit/s and Froude number of 0.26. The results showed that the trend of maximum scour depth change with increasing permeability decreased. The scour depth in gabion groines is much higher than rod groines with the same permeability. Also, the effect of increasing the row spacing of two-row groines on the prediction of the maximum scour depth for the zigzag type is additive and for the parallel type it is decreasing.