Author(s): Michele Palermo, Stefano Pagliara
Linked Author(s): Michele Palermo
Keywords: Arched sills, curved rivers, river morphology, scour process
Abstract: Hydraulic structures functioning and erosive processes occurring in curved rivers are still under-investigated. In the present paper, an experimental analysis is conducted focusing on a particular structure typology: rock arched sills. This type of structure is similar to linear rock sills, but they are shaped in such a way that they can more properly orientate the flow. The analysis of this structure typology is conducted in a dedicated flume. The laboratory flume is characterized by four different curved branches. One uniform channel bed material is used to simulate the mobile bed and experimental tests are carried out up to when the equilibrium scour configuration is reached. Experiments are conducted for different flow discharges and tailwater levels. Furthermore, different sills are tested, i. e. , the height of the sill from the original bed level is varied. In addition, the transversal location of sills is also varied. Namely, sills are located in different spatial positions and in succession in the same curve, in order to test the mutual interference on the scour process. When the equilibrium scour condition is achieved, the channel bed morphology is carefully surveyed. The analysis of the experimental evidences allows establishing that different scour typologies take place. In addition, it is experimentally proven that the maximum scour depth, such as the scour hole length, are significantly affected by the channel curvature. Experimental results are elaborated and empirical relationships are furnished in order to estimate the maximum scour lengths. This paper could be useful for a correct design of this structure typology. Nevertheless, further experimental tests are required in order to optimize the location of such structures and to better understand the physics of the scour mechanism in a larger range of both hydraulic parameters and geometric configurations
Year: 2017