Effect of Hollow Semi-Circular Baffles Arrangement on Local Scour Downstream Hydraulic Structures

Document Type : Research Studies

Authors

1 Graduate Student, Irrigation and Hydraulics Engineering Dept. Mansoura University, Mansoura 35516, Egypt

2 Prof. of, Irrigation and Hydraulics Engineering Dept., Mansoura University, Mansoura 35516, Egypt

3 Associate Prof. of Irrigation and Hydraulics Engineering Dept., Mansoura University, Mansoura 35516, Egypt

Abstract

The purpose of this research is to examine the effect of using hollow semi-circular baffles, on scour hole dimensions downstream hydraulic heading-up structures. Different flow conditions and various geometrical parameters are considered.  Fifty-four experiments are carried out under live bed scour conditions. The experiments consist of six sets, each one forced to the same flow conditions, but represents a different suggested geometrical arrangement of the baffles. Results showed that the best position of the baffle is located at the first one- third of the floor length with relative diameter equals to 0.74 to the initial water depth (gate opening). This position causes reduction equal to about 50% for the maximum depth of scour, with respective to the case of flat floor (no baffles). While the extended length of the scour is reduced to about 31%. On the other hand, the second baffles position, at the two-thirds of the floor length reduces only the relative scour length to about 57%.  Based on the experimental results, empirical dimensionless relationships are developed for both maximum scour length and depth

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