امین محمودی

In addition to hydrodynamic flows around bridge pier, the bridges in the river’s meander paths are also affected by flows inside the bend. So, their scouring will be doubled. Various protective methods are used to change flow pattern and reduction of vortex intensity around bridge pier and consequently scouring reduction. One of these methods is the use of submerged vanes on the upstream bridge. In this study, the reduction of scouring around single pier and pier group influenced the percent of submerged vanes submersion with piers located in bend’s 90 degrees situation, were investigated. The reduction of scouring of piers altered in 60 and 120 degrees position was simulated using SSIIM software. All experiments were done by 180 –degree sharp bend flume and whit the ratio of the central radius to the channel width equal to 2. In these experiments, variable parameters were assumed the number of pier, direction of pier against flow, position of pier, and the percent of submerged vanes submersion in the bend. In all tests using submerged vanes, the results show that the maximum depth of scouring around pier and scour volume was decreased. Reduction of maximum scour depth in the triplet pier group test aligned with direction of flow with triplet vanes and 75% submersion, was approximately 55%. Also, in the triplet pier group test with perpendicular to direction of flow with twin vanes and 25% submersion, the minimum impact was nearly 5%. Maximum scour volume reduction was observed about 53%, in single pier test with 50% submersion triplet vanes. The effect of using two submerged vanes, increasing the sedimentary height and three submerged vanes led to a decrease in maximum sedimentary height. The position of its formation in tests with two and three vanes was at a distance of approximately 40 and 87 times the diameter of the pier from bend center, respectively. In the simulation section, experiments were investigated using SSIIM software. In the experiments with piers