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Bridge pier local scouring is a crucial factor in bridge destruction. Studies from different researchers have presented solutions to control this phenomenon. These solutions are divided into two parts, namely, direct and indirect protection. In the direct method, the bed is armoured against scouring whereas in the indirect methods the flow pattern around the pier is changed with geometric parameters. This study defined an element called the deflector structure (flow diverter) to divert the bed’s flow streamline in front of the pier. Experimental scenarios were defined by stabilizing the flow conditions with 0.70, 0.83, and 0.97 relative velocities ( ) and 15-, 30-, and 45-degree wedge deflector structure angles with flow direction for two piers with square and circular cross-sections. The results showed that the dimensionless scour depth parameter ( ) close to the particle movement threshold ( ) was reduced by 70 to 75%, respectively relative to the control model for square and circle cross-section. Changing the angle from 45 to 30 and 15 degrees reduces the local pier scouring and increases the deflector structure’s effectiveness.

Flip buckets are commonly used to discharge flow from a hydraulic structure to the downstream as ski jump when flow velocity is large. One way to increase energy dissipation in flip bucket spillways is the deflector application. In this study deflector is a wedge-shaped structure which creates changes in part of flow trajectory. In this study, the deflector was continuously used across the channel, and energy dissipation caused by the mentioned deflector was measured. For the purpose of this study, after making the physical model, experiments were conducted by using four Froude’s numbers 5.55, 4.72, 3.93 and 3.13 by using deflectors with 3, 6, 9 cm lengths, and angles equal to 12˚,17˚, 22˚, 27˚, 32˚, 37˚ and 42˚. Data analysis showed that deflectors with different angles cause an increase in energy dissipation. Also when the Froude’s number increases, the amount of energy dissipation will increase. The greatest difference of energy dissipation with state without deflector which occurs in Froude’s number of 3.93 was equal to 22.7% and was belong to deflector with 6cm length and 27 degree. In average the deflector with angles of 27 degrees has the greatest energy dissipation. This amount of energy dissipation for deflectors with 3, 6, 9 cm in lengths were equals to 68.2%, 72.5%, 51.6%respenctively and which occur in Froude’s number equal to 5.55