Experimental Investigation of the Performance of Triangular Vanes on Bed Topography in Straight Rivers.

Document Type : Research Paper

Authors

1 M.Sc. Graduate, Faculty of Water Science Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran

2 Prof., Faculty of Water Science Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran

3 Assistant Prof., Faculty of Water Science Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran

Abstract

             Spur dikes are one of the structures used for protection of river banks from erosion and rivers organization. They are usually rectangular and perpendicular to the flow. Unfortunately, the scour development in the tip of those can lead damage to the structure. Furthermore, sedimentation between the spur dikes as well as increasing the flow velocity in the middle of the channel due to the large obstruction, are among the factors that create problems for aquatic life of the river. These problems are minimal in the triangular vanes. The main purpose of this paper is to evaluate the performance of the triangular vanes on bed topography changes in the different flow conditions. For this reason, some tests were carried out at a straight flume for different flow conditions (five Froude numbers of 0.18, 0.20, 0.22, 0.24 and 0.26) by installing series of triangular vanes with space of 4Le (Le is the effective length of structure) at the angle of 30 degrees to the upstream bank. At the end of each test the bed topography was measured by laser distance measurer. The results showed that, the geometric dimension of the scour hole for the rectangular spur dikes was larger than that for the triangular vanes. On average, the length and depth of scour hole for the rectangular spur dikes were 1.3 and 1.5 times higher in comparison to those for triangular vanes, respectively. In addition, the position of the maximum scour depth for the triangular vanes was about 40% farther from the bank than that case of rectangular spur dikes that was an advantage for the triangular vanes.

Keywords

References

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Water and Soil Science
Volume 30, Issue 2
June 2020
Pages 91-102

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